Salsolinol is an endogenous catechol isoquinoline detected in humans. Salsolinol was detected in urine of parkinsonian patients administered with L-DOPA. This finding stimulated the studies on Salsolinol derivatives in the brain, and gave new aspects of the endogenous alkaloids, which had been considered to occur only in plants. In normal non-alcoholic subjects and alcoholics, Salsolinol and O-methylated Salsolinol were found in urine, cerebrospinal fluid and brains. Salsolinol has an asymmetric center at first position and exists as (R)- and (S)enantiomer. The (R)enantiomer of Salsolinol is predominant in urine from healthy volunteers. Only the (R)enantiomers of Salsolinol and N-methylated Salsolinol occur in the human brain, cerebrospinal fluid (CSF) and intraventricular fluid (IVF), and the (S)enantiomers were not detected. (R)salsolinol synthase catalyzes the enantio-selective synthesis of (R)Salsolinol and 1-carboxyl(R)Salsolinol from dopamine with acetaldehyde or pyruvic acid. The N-methylation of (R)salsolinol into N-methylsalsolinol (NMSal) is catalyzed by two N-methyltransferases with different optimum pH, at pH 7.0 and 8.4. NM(R)Salsolinol is enzymatically oxidized into 1,2-dimethyl-6,7-dihydroxyisoquinolinium ion (DMDHIQ+) by an oxidase sensitive to semicarbaside and also non-enzymatically by autoxidation. NM(R)Salsolinol and its precursor, dopamine, were found to occur selectively in the nigro-striatum, whereas (R)Salsolinol distributes uniformly among the brain regions. (PMID 14697894).
4-Carboxyphenylglycine is a group I metabotropic glutamate receptor (mGlu) antagaonist by blocking the cystine/glutamate exchanger. In addition, it has modulating effect on the central action of NMDA receptor antagonist. It plays a role in synaptic plasticity and excitability, long term potentiation and long term depression.
D-Tartaric acid is found in loquat. D-Tartaric acid is found combined as Chicoric acid and it is an unnatural tartaric acid isomer. (Wikipedia
1-(beta-D-Ribofuranosyl)-1,4-dihydronicotinamide is the reduced form of nicotinamide riboside. Nicotinamide riboside or NR is a natural product found in milk. It can exist in both the oxidized and reduced form. Nicotinamide riboside is a newly discovered precursor to NAD ( nicotinamide adenine dinucleotide). Nicotinamide riboside kinases (Nrks) are essential for this NAD synthesis pathway. Nrks actually constitute a distinct pathway of NAD biosynthesis and it appears that nicotinamide riboside may be the only vitamin precursor that supports neuronal NAD synthesis (PMID: 18429699). NAD homeostasis is related to the free radical-mediated production of reactive oxygen species responsible for irreversible cellular damage in infectious disease, diabetes, inflammatory syndromes, neurodegeneration and cancer. (PMID: 18508649). Baseline requirements for NAD synthesis can be met either with dietary tryptophan or with less than 20 mg of daily niacin, which consists of nicotinic acid and/or nicotinamide. Reduced nicotinamide riboside is also known to be a substrate for ribosyldihydronicotinamide dehydrogenase (EC 1.10.99.2). It is also a substrate for purine-nucleoside phosphorylase (PNP) - (PMID: 9030766).
1-Methyladenine is the product of reaction between 1-methyladenosine and water which is catalyzed by 1-methyladenosine nucleosidase (EC:3.2.2.13). 1-Methyladenine is a product of alkylation damage in DNA which can be repaired by damage reversal by oxidative demethylation, a reaction requiring ferrous iron and 2-oxoglutarate as cofactor and co-substrate, respectively (PMID:15576352). 1-Methyladenine is found to be associated with adenosine deaminase (ADA) deficiency, which is an inborn error of metabolism.
1-Methylguanine is a naturally occurring modified purine derived from tRNA, found in elevated levels in the serum and urine of cancer patients (PMID:2413515). Increase of 1-methylguanine in the urine of colorectal tumor bearing patients, has been justified either by a more rapid turnover of nucleic acids in tumor tissue or by an increase in the extent of their methylation (PMID:9069642).
1-Methylguanosine is a methylated nucleoside. It is known that some modified, especially methylated, nucleosides originating from RNA degradation are excreted in abnormal levels in the urine of patients with malignant tumours. These nucleosides have been proposed as tumour markers. Their measurement could provide a non-invasive diagnostic method, help identify different cancers, and monitor any therapeutic effects (PMID:9129323).
1-Methylhistamine, also known as H137, belongs to the class of organic compounds known as 2-arylethylamines. These are primary amines that have the general formula RCCNH2, where R is an organic group. 1-Methylhistamine exists in all living organisms, ranging from bacteria to humans. Within humans, 1-methylhistamine participates in a number of enzymatic reactions. In particular, S-adenosylhomocysteine and 1-methylhistamine can be biosynthesized from S-adenosylmethionine and histamine; which is mediated by the enzyme histamine N-methyltransferase. In addition, 1-methylhistamine can be converted into methylimidazole acetaldehyde through its interaction with the enzyme amine oxidase [flavin-containing] a. In humans, 1-methylhistamine is involved in histidine metabolism. 1-Methylhistamine is a potentially toxic compound.
1-Methylhypoxanthine is a methylated hypoxanthine. Hypoxanthine is a naturally occurring purine derivative and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
1-Methyluric acid is one of the three main theophylline metabolites in man. 1-Methyluric acid is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline, and theobromine). Methyluric acids can be distinguished from uric acid via simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase, or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 superfamily, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis (PMID:11712316, 15833286, 3506820, 15013152, 4039734, 9890610).
1-Methyluric acid is one of the three main theophylline metabolites in man. 1-Methyluric acid is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline, and theobromine). Methyluric acids can be distinguished from uric acid via simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase, or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 superfamily, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis (PMID:11712316, 15833286, 3506820, 15013152, 4039734, 9890610).
1,3-Dimethyluric acid is a product of theophylline metabolism in man. 1,3-Dimethyluric acid is one of the purine components in urinary calculi. Methylated purines originate from the metabolism of methylxanthines (caffeine, theophylline and theobromine). Methyluric acids are indistinguishable from uric acid by simple methods routinely used in clinical laboratories, requiring the use of high-performance liquid chromatography (HPLC). Purine derivatives in urinary calculi could be considered markers of abnormal purine metabolism. The content of a purine derivative in stone depends on its average urinary excretion in the general population, similarity to the chemical structure of uric acid, and content of the latter in stone. This suggests that purines in stones represent a solid solution with uric acid as solvent. It is also plausible that methylxanthines, ubiquitous components of the diet and drugs, are involved in the pathogenesis of urolithiasis. Caffeine is metabolized via successive pathways mainly catalyzed by CYP1A2, xanthine oxidase or N-acetyltransferase-2 to give 14 different metabolites. CYP1A2 activity shows an inter-individual variability among the population. CYP1A2, an isoform of the CYP1A cytochrome P450 super-family, is involved in the metabolism of many drugs and plays a potentially important role in the induction of chemical carcinogenesis. (PMID:11712316, 15833286, 3506820, 15013152, 4039734).
1, 5-Anhydrosorbitol or 1,5-anhydroglucitol (1,5-AG) is a validated marker of short-term glycemic control. This substance is derived mainly from food, is well absorbed in the intestine, and is distributed to all organs and tissues. It is metabolically stable, being excreted in the urine when its level exceeds the renal threshold. It is reabsorbed in the renal tubules and is competitively inhibited by glucosuria, which leads to a reduction in its level in serum. The correlation between this reduction and the amount of glucose present in urine is so close that 1,5 AG can be used as a sensitive, day-to-day, real-time marker of glycemic control. It provides useful information on current glycemic control and is superior to both hemoglobin A1C and fructosamine in detecting near-normoglycemia. 1,5-AG in human plasma has been proposed for several years as a short-term, retrospective marker of glycemic control and seems to be the most suitable parameter for monitoring glucose excursions. The decrease in serum 1,5-AG is very sensitive to urinary glucose excretion. It is a metabolically inert polyol that competes with glucose for reabsorption in the kidneys. Otherwise stable levels of 1,5-AG are rapidly depleted as blood glucose levels exceed the renal threshold for glucosuria. 1,5-AG is also more tightly associated with glucose fluctuations and postprandial glucose (PMID:18088226, 12166605, 7783360, 8940824).
1,7-Dimethyluric acid is the major urinary caffeine metabolite that is produced in the human body. 1,7-Dimethyluric acid is formed during caffeine metabolism and the process is catalyzed primarily by CYP2A6 (PMID: 18715882).
11-beta-hydroxyandrosterone-3-glucuronide is a natural human metabolite of 11beta-hydroxyandrosterone generated in the liver by UDP glucuonyltransferase. Glucuronidation is used to assist in the excretion of toxic substances, drugs or other substances that cannot be used as an energy source. Glucuronic acid is attached via a glycosidic bond to the substance, and the resulting glucuronide, which has a much higher water solubility than the original substance, is eventually excreted by the kidneys.
2-Aminoisobutyric acid, also known as alpha-methylalanine or a-aminoisobutanoate, belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). 2-Aminoisobutyric acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. 2-Aminoisobutyric acid exists in all living organisms, ranging from bacteria to humans. Outside of the human body, 2-Aminoisobutyric acid has been detected, but not quantified in cow milk. Aminoisobutyric acid is a nonprotein amino acid (is an end product of pyrimidine metabolism) excreted in the urine of about 5% of healthy individuals (PMID 14806475), and high excretion is an autosomal recessive phenotype (PMID 13058271).
D-alpha-Aminobutyric acid (AABA), also known as alpha-aminobutyrate, (R)-2-aminobutanoic acid or D-homoalanine, belongs to the class of organic compounds known as D-alpha-amino acids. These are alpha amino acids which have the D-configuration of the alpha-carbon atom. D-alpha-aminobutyric acid is an optically active form of alpha-aminobutyric acid having D-configuration. It is an enantiomer of a L-alpha-aminobutyric acid and a non-proteinogenic amino acid. Alpha-aminobutyric acid is one of the three isomers of aminobutyric acid. The two others are the neurotransmitter Gamma-Aminobutyric acid (GABA) and Beta-Aminobutyric acid (BABA) which is known for inducing plant disease resistance. Optically active organic compounds found in meteorites typically exist in racemic form, yet life on Earth has almost exclusively selected for L- over D-enantiomers of amino acids. D-enantiomers of non-proteinogenic amino acids are known to inhibit aerobic microorganisms. D-alpha-aminobutyric acid has been shown to inhibit microbial iron reduction by a number of Geobacter strains including Geobacter bemidjiensis, Geobacter metallireducens and Geopsychrobacter electrodiphilus (PMID: 25695622). D-alpha-Aminobutyric acid is a known substrate of D-amino acid oxidase (PMID: 6127341).
O-Phosphoethanolamine, also known as PEA, phosphorylethanolamine, colamine phosphoric acid or ethanolamine O-phosphate, belongs to the class of organic compounds known as phosphoethanolamines. Phosphoethanolamines are compounds containing a phosphate linked to the second carbon of an ethanolamine. O-Phosphoethanolamine is used in the biosynthesis of two different types of phospholipids: glycerophospholipids and sphingolipids. O-Phosphoethanolamine exists in all living species, ranging from bacteria to plants to humans. Within humans, O-phosphoethanolamine participates in a number of enzymatic reactions. In particular, cytidine triphosphate and O-phosphoethanolamine can be converted into CDP-ethanolamine; which is mediated by the enzyme ethanolamine-phosphate cytidylyltransferase. In addition, O-phosphoethanolamine can be biosynthesized from ethanolamine; which is catalyzed by the enzyme choline/ethanolamine kinase. In humans, O-phosphoethanolamine is involved in phosphatidylcholine biosynthesis. O-phosphoethanolamine is also a product of the metabolism of sphingolipids. In particular, sphinglipids are metabolized in vivo to phosphorylethanolamine and a fatty aldehyde, generally palmitaldehyde. Both metabolites are ultimately converted to glycerophospholipids. The lipids are first phosphorylated by a kinase and then cleaved by the pyridoxal-dependent sphinganine-1-phosphate aldolase. Elevated urine levels of O-Phosphoethanolamine or PEA can be used to help in the diagnosis of Hypophosphatasia (HPP). Reference ranges for urinary PEA vary according to age and somewhat by diet, and follow a circadian rhythm. Outside of the human body, O-phosphoethanolamine has been detected, but not quantified in, several different foods, such as oxheart cabbages, anises, shiitakes, abalones, and teffs.
2-aminophenol sulphate is a metabolite found in urine of individuals that have consumed whole grains.  It is a particularly strong biomarker for whole grain rye bread consumption (PMID: 23307617).
2-aminophenol sulphate is a metabolite found in urine of individuals that have consumed whole grains.  It is a particularly strong biomarker for whole grain rye bread consumption (PMID: 23307617).
Deoxyadenosine is a derivative of the nucleoside adenosine. It is composed of adenine attached to a deoxyribose moiety via a N9-glycosidic bond. Deoxyribose differs from ribose by the absence of oxygen in the 3' position of its ribose ring. Deoxyadenosine is a critical component of DNA. When present in sufficiently high levels, deoxyadensoine can act as an immunotoxin and a metabotoxin. An immunotoxin disrupts, limits the function, or destroys immune cells. A metabotoxin is an endogenous metabolite that causes adverse health effects at chronically high levels. Chronically high levels of deoxyadenosine are associated with adenosine deaminase (ADA) deficiency, an inborn error of metabolism. ADA deficiency damages the immune system and causes severe combined immunodeficiency (SCID). People with SCID lack virtually all immune protection from bacteria, viruses, and fungi. They are prone to repeated and persistent infections that can be very serious or life-threatening. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. The main symptoms of ADA deficiency are pneumonia, chronic diarrhea, and widespread skin rashes. The mechanism by which dATP functions as an immunotoxin is as follows: because deoxyadenosine is a precursor to dATP, a buildup of dATP in cells inhibits ribonucleotide reductase and prevents DNA synthesis, so cells are unable to divide. Since developing T cells and B cells are some of the most mitotically active cells, they are unable to divide and propagate to respond to immune challenges. High levels of deoxyadenosine also lead to an increase in S-adenosylhomocysteine, which is toxic to immature lymphocytes.
2-Hydroxyethanesulfonate (also known as 2-Hydroxyethanesulfonic acid or isethionic acid) is an organosulfur compound containing a short chain alkane sulfonate linked to a hydroxyl group. It is a water-soluble liquid used in the manufacture of mild, biodegradable, and high-foaming anionic surfactants. These surfactants provide gentle cleansing and a soft skin feel. 2-Hydroxyethanesulfonate forms a colourless, syrupy, and strongly acidic liquid that can form detergents with oleic acid. 2-Hydroxyethanesulfonate is frequently used in the industrial production of taurine. Mammals are also able to endogenously synthesize 2-hydroxyethanesulfonate via taurine through a possible enzymatic deamination process (PMID: 14490797). 2-Hydroxyethanesulfonate can be found in both human plasma and urine (PMID: 1159536, PMID: 6066118). Higher plasma levels of 2-hydroxyethanesulfonate have been shown to be protective against type 2 diabetes.
2-Hydroxyethanesulfonate (also known as 2-Hydroxyethanesulfonic acid or isethionic acid) is an organosulfur compound containing a short chain alkane sulfonate linked to a hydroxyl group. It is a water-soluble liquid used in the manufacture of mild, biodegradable, and high-foaming anionic surfactants. These surfactants provide gentle cleansing and a soft skin feel. 2-Hydroxyethanesulfonate forms a colourless, syrupy, and strongly acidic liquid that can form detergents with oleic acid. 2-Hydroxyethanesulfonate is frequently used in the industrial production of taurine. Mammals are also able to endogenously synthesize 2-hydroxyethanesulfonate via taurine through a possible enzymatic deamination process (PMID: 14490797). 2-Hydroxyethanesulfonate can be found in both human plasma and urine (PMID: 1159536, PMID: 6066118). Higher plasma levels of 2-hydroxyethanesulfonate have been shown to be protective against type 2 diabetes.
ortho-Hydroxyphenylacetic acid, also known as (o-hydroxyphenyl)acetate or 2-hydroxybenzeneacetic acid, is a member of the class of compounds known as 2(hydroxyphenyl)acetic acids. 2(Hydroxyphenyl)acetic acids are phenylacetic acids that carry a hydroxyl group at the 2-position. ortho-Hydroxyphenylacetic acid is slightly soluble (in water) and a weakly acidic compound (based on its pKa). ortho-Hydroxyphenylacetic acid can be found in a number of food items such as natal plum, lemon verbena, half-highbush blueberry, and parsley, which makes ortho-hydroxyphenylacetic acid a potential biomarker for the consumption of these food products. ortho-Hydroxyphenylacetic acid can be found primarily in blood, feces, and urine. Moreover, ortho-hydroxyphenylacetic acid is found to be associated with phenylketonuria, which is an inborn error of metabolism. ortho-Hydroxyphenylacetic acid is a substrate of the enzyme oxidoreductases (EC 1.14.13.-) in the pathway styrene degradation (KEGG). ortho-Hydroxyphenylacetic acid is also a microbial metabolite.
This colourless crystalline solid is used in peptide synthesis. It is well known to form hydrogen bonded structures somewhat related to the base-pairing mechanism found in RNA and DNA. It is also a classic case of a molecule that exists as tautomers. Some publications only focus one of the two possible patterns, and neglect the influence of the other. For example, to calculation of the energy difference of the two tautomers in a non-polar solution will lead to a wrong result if a large quantity of the substance is on the side of the dimer in an equilibrium. The direct tautomerisation is not energetically favoured, but a dimerisation followed by a double proton transfer and dissociation of the dimer is a self catalytic path from one tautomer to the other. Protic solvents also mediate the proton transfer during the tautomerisation.
deaminated metabolite of glutamine in csf of patients with hepatic coma; intermediate in the detoxification of ammonia in brain; structure.
2-Methoxyacetaminophen glucuronide is classified as a member of the class of compounds known as phenolic glycosides. Phenolic glycosides are organic compounds containing a phenolic structure attached to a glycosyl moiety. Some examples of phenolic structures include lignans, and flavonoids. Among the sugar units found in natural glycosides are D-glucose, L-Fructose, and L rhamnose. 2-Methoxyacetaminophen glucuronide is considered to be soluble (in water) and a moderately acidic compound.
2-Methylhippuric acid is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases, the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine <--> CoA + N-acylglycine. 2-Methylhippuric acid is a metabolite of xylene which is an aromatic hydrocarbon widely used as a solvant. Its level can be measured in the urine of workers exposed to xylene (PMID:8689499). 2-Methylhippuric acid is an endogenous phenolic acid metabolite detected after the consumption of whole grain.
Citraconic acid, also known as 2-methylmaleate or methylmaleic acid, belongs to the class of organic compounds known as methyl-branched fatty acids. These are fatty acids with an acyl chain that has a methyl branch. Usually, they are saturated and contain only one or more methyl group. However, branches other than methyl may be present. Citraconic acid is a dicarboxylic acid consisting of maleic acid having a methyl substituent at the 2-position. Citraconic acid exists as a white solid. It is the cis-isomer of mesaconic acid and is one of the pyrocitric acids formed upon the heating of citric acid.  Citraconic acid has been detected in the urine of both normal and fasting individuals (PMID: 6778884). Citraconic acid is also elevated in the urine of individuals with methylmalonic acidaemia who have suffered ketotic attacks (PMID: 116077).  Altered serum levels of citraconic acid have been detected in patients with primary biliary cholangitis (PMID: 28400566).
2-Oxoarginine is a guanidino compound metabolite of arginine catabolism. 2-Oxoarginine levels are increased in patients with argininemia (OMIM:207800). Argininemia, characterized by arginase deficiency (EC 3.5.3.1, catalyzes the last step of the urea cycle) is an autosomal recessive inborn error of metabolism caused by a defect in the final step in the urea cycle, the hydrolysis of arginine to urea and ornithine. Accumulation of arginine metabolites (such as guanidino compounds) especially 2-oxoarginine, may produce the central nervous system damage in argininemia. (PMID: 3433275 , 1588833 , 1690873 , 819629). 2-Oxoarginine has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
2-Pyrocatechuic acid is a normal human benzoic acid metabolite found in plasma (PMID 16351159), and is normally found with increased levels after consumption of many nutrients and drugs, i.e.: cranberry juice (PMID 14733499), aspirin ingestion. (PMID 3342084) It has been found associated with idiopathic oro-facial pain due to stress (oxidative stress might enhance the production of free radicals); it has been suggested that OH radicals are responsible for the production of many systemic and local tissue injury diseases which may initially manifest as pain syndrome, and 2-Pyrocatechuic acid is a biological marker for the detection and quantification of OH radicals, and patients had significantly increased circulating levels of 2-Pyrocatechuic acid after aspirin ingestion than control subjects. (PMID 7748148).
2,3-Dihydroxyvaleric acid (DHVA) belongs to the class of organic compounds known as hydroxy fatty acids. These are fatty acids in which the chain bears a hydroxyl group. This compound has been detected in extracts from the purple carrot (https://doi.org/10.3390/app10238493). It is likely a hydroxylation derivative of the more common 2-hydroxyvaleric acid (an algal metabolite derived from a valeric acid) or 3-hydroxyvaleric acid (a 5-carbon ketone body made from odd carbon fatty acids in the liver). Very little is known about the origin of this particular hydroxy fatty acid.
2,3-Dihydroxyvaleric acid (DHVA) belongs to the class of organic compounds known as hydroxy fatty acids. These are fatty acids in which the chain bears a hydroxyl group. This compound has been detected in extracts from the purple carrot (https://doi.org/10.3390/app10238493). It is likely a hydroxylation derivative of the more common 2-hydroxyvaleric acid (an algal metabolite derived from a valeric acid) or 3-hydroxyvaleric acid (a 5-carbon ketone body made from odd carbon fatty acids in the liver). Very little is known about the origin of this particular hydroxy fatty acid.
2,6-Dimethylpyrazine, also known as fema 3273 or 2,5-DMP, belongs to the class of organic compounds known as pyrazines. Pyrazines are compounds containing a pyrazine ring, which is a six-member aromatic heterocycle, that consists of two nitrogen atoms (at positions 1 and 4) and four carbon atoms. Alkylpyrazines are chemical compounds based on pyrazine with different substitution patterns. 2,6-Dimethylpyrazine is a cocoa, roastbeef, and roastednut tasting compound. 2,6-Dimethylpyrazine has been detected, but not quantified, in tea. This could make 2,6-dimethylpyrazine a potential biomarker for the consumption of these foods. Alkylpyrazines are also formed during the cooking of some foods via Maillard reactions. It occurs naturally in asparagus, black or green tea, crispbread, malt, raw shrimp, soya, squid, Swiss cheeses, and wheat bread. It occurs naturally in baked potato, black or green tea, crispbread, French fries, malt, peated malt, raw asparagus, roasted barley, roasted filberts or pecans, squid, wheat bread, wild rice (Zizania aquatica), and wort.
Deoxyinosine is a nucleoside that is formed when hypoxanthine is attached to a deoxyribose ring (also known as a ribofuranose) via a beta-N9-glycosidic bond. Deoxyinosine is found in DNA while inosine is found in RNA. Inosine is a nucleic acid important for RNA editing. Adenosine deaminase (ADA) catalyzes the conversion of adenosine and deoxyadenosine to inosine and deoxyinosine, respectively. ADA-deficient individuals suffer from severe combined immunodeficiency (SCID) and are unable to produce significant numbers of mature T or B lymphocytes. This occurs as a consequence of the accumulation of ADA substrates or their metabolites. Inosine is also an intermediate in a chain of purine nucleotides reactions required for muscle movements. Moreover, deoxyinosine is found to be associated with purine nucleoside phosphorylase (PNP) deficiency, which is an inborn error of metabolism.
3-Chlorotyrosine, a specific marker of myeloperoxidase-catalyzed oxidation, is markedly elevated in low density lipoprotein isolated from human atherosclerotic intima. (PMID 9151778). In particular, myeloperoxidase halogenates tyrosine residues in plasma proteins and and generates 3-chlorotyrosine (CY). The detection of free chlorotyrosine in blood or urine arises from the degradation of these chlorinated proteins. CY concentrations may be useful for monitoring the activation of neutrophils in asthmatic patients (PMID 15196282).
3-Furoic acid is an organic acid regularly occurring in urine of healthy individuals. (PMID 2338430). 3-Furoic acid is also a compound found in honey and honeydew samples (PMID 11403496), and is a structural analog of nicotinic acid (niacin, a vitamin of the B complex). (PMID 12563315).
3-Hydroxyanthranilic acid, also known as 2-amino-3-hydroxy-benzoate or 3-ohaa, belongs to the class of organic compounds known as hydroxybenzoic acid derivatives. Hydroxybenzoic acid derivatives are compounds containing a hydroxybenzoic acid (or a derivative), which is a benzene ring bearing a carboxyl and a hydroxyl groups. 3-Hydroxyanthranilic acid is a drug. 3-Hydroxyanthranilic acid exists in all living species, ranging from bacteria to humans. Within humans, 3-hydroxyanthranilic acid participates in a number of enzymatic reactions. In particular, 3-hydroxyanthranilic acid and L-alanine can be biosynthesized from L-3-hydroxykynurenine through the action of the enzyme kynureninase. In addition, 3-hydroxyanthranilic acid can be converted into cinnavalininate through the action of the enzyme catalase. 3-Hydroxyanthranilic acid is an intermediate in the metabolism of tryptophan. In humans, 3-hydroxyanthranilic acid is involved in tryptophan metabolism. Outside of the human body, 3-hydroxyanthranilic acid has been detected, but not quantified in brassicas. This could make 3-hydroxyanthranilic acid a potential biomarker for the consumption of these foods. It is new antioxidant isolated from methanol extract of tempeh. It is effective in preventing autoxidation of soybean oil and powder, while antioxidant 6,7,4'-trihydroxyisoflavone is not.
3-Hydroxyphenylacetic acid is a rutin metabolite and an antioxidant. It has a protective biological activity in human. It is a substrate of enzyme 4-hydroxyphenylacetate 3-monooxygenase [EC 1.14.13.3] in the pathway tyrosine metabolism (KEGG, PMID 155437). 3-Hydroxyphenylacetic acid is found to be associated with phenylketonuria, which is an inborn error of metabolism. It is also a marker of gut Clostridium species. Higher levels are associated with higher levels of Clostridia (PMID: 27123458). 3-Hydroxyphenylacetic acid can also be found in Klebsiella (PMID: 1851804).
Indoleacetic acid (IAA) is a breakdown product of tryptophan metabolism and is often produced by the action of bacteria in the mammalian gut. Higher levels of IAA are associated with bacteria from Clostridium species including C. stricklandii, C. lituseburense, C. subterminale, and C. putrefaciens (PMID: 12173102). IAA can be found in Agrobacterium, Azospirillum, Bacillus, Bradyrhizobium, Clostridium, Enterobacter, Pantoea, Pseudomonas, Rhizobium (PMID: 12173102, PMID: 17555270, PMID: 12147474, PMID: 19400643, PMID: 9450337, PMID: 21397014) (https://link.springer.com/chapter/10.1007/978-1-4612-3084-7_7) (https://escholarship.org/uc/item/1bf1b5m3). Some endogenous production of IAA in mammalian tissues also occurs. It may be produced by the decarboxylation of tryptamine or the oxidative deamination of tryptophan. IAA frequently occurs at low levels in urine and has been found in elevated levels in the urine of patients with phenylketonuria (PMID: 13610897). IAA has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Using material extracted from human urine, it was discovered by Kogl in 1933 that indoleacetic acid is also an important plant hormone (PMID: 13610897). Specifically, IAA is a member of the group of phytohormones called auxins. IAA is generally considered to be the most important native auxin. Plant cells synthesize IAA from tryptophan (Wikipedia). IAA and some derivatives can be oxidized by horseradish peroxidase (HRP) into cytotoxic species. IAA is only toxic after oxidative decarboxylation; the effect of IAA/HRP is thought to be due in part to the formation of methylene-oxindole, which may conjugate with DNA bases and protein thiols. IAA/HRP could be used as the basis for targeted cancer, a potential new role for plant auxins in cancer therapy (PMID: 11163327).
3-Indolebutyric acid is an indolic tryptophan metabolite occasionally found in human urine. (PMID:7130309). 3-Indolebutyric acid is a plasma and urinary tryptophan-related metabolite related to metabolic and skin diseases. (PMID:15206797). Plasma levels of tryptophan metabolites in the umbilical vein and artery are significantly higher than those in the maternal vein. (PMID:1506727). 3-Indolebutyric acid has been shown to accelerated glucose uptake in the rat diaphragm. (PMID:6025019). 3-Indolebutyric acid is also a microbial netabolite, urinary indole-3-butyrate is produced by Clostridia sp. (PMID:6630445).
Indoxyl sulfate is a dietary protein metabolite and also a metabolite of the common amino acid tryptophan. It has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). It is a circulating uremic toxin stimulating glomerular sclerosis and interstitial fibrosis. Indoxyl sulfate is one of the well-known substances of a group of protein-bound uremic retention solutes. Indoxyl sulfate increases the rate of progression of renal failure. In plasma, indoxyl sulfate is a protein-bound uremic solute that induces endothelial dysfunction by inhibiting endothelial proliferation and migration in vitro. Some studies suggest that indoxyl sulfate is also involved in oxidative stress. In hemodialyzed patients, serum levels of indoxyl sulfate are associated with levels of pentosidine, a marker of carbonyl and oxidative stress. In vitro, indoxyl sulfate increases reactive oxygen species (ROS) production in tubular cells and increases NAD(P)H oxidase activity in endothelial cells. Indoxyl sulfate impairs osteoblast function and induces abnormalities of bone turnover. Indoxyl sulfate strongly decreases the levels of glutathione, one of the most active antioxidant systems of the cell (PMID: 10681668 , 14681860 , 17471003 , 17403109). Indoxyl sulfate is a microbial metabolite found in Escherichia (PMID: 19946322).
Indoxyl sulfate is a dietary protein metabolite and also a metabolite of the common amino acid tryptophan. It has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). It is a circulating uremic toxin stimulating glomerular sclerosis and interstitial fibrosis. Indoxyl sulfate is one of the well-known substances of a group of protein-bound uremic retention solutes. Indoxyl sulfate increases the rate of progression of renal failure. In plasma, indoxyl sulfate is a protein-bound uremic solute that induces endothelial dysfunction by inhibiting endothelial proliferation and migration in vitro. Some studies suggest that indoxyl sulfate is also involved in oxidative stress. In hemodialyzed patients, serum levels of indoxyl sulfate are associated with levels of pentosidine, a marker of carbonyl and oxidative stress. In vitro, indoxyl sulfate increases reactive oxygen species (ROS) production in tubular cells and increases NAD(P)H oxidase activity in endothelial cells. Indoxyl sulfate impairs osteoblast function and induces abnormalities of bone turnover. Indoxyl sulfate strongly decreases the levels of glutathione, one of the most active antioxidant systems of the cell (PMID: 10681668 , 14681860 , 17471003 , 17403109). Indoxyl sulfate is a microbial metabolite found in Escherichia (PMID: 19946322).
3-Methoxytyrosine, also known as 3-O-methyldopa or vanilalanine, belongs to the class of organic compounds known as tyrosine and derivatives. Tyrosine and derivatives are compounds containing tyrosine or a derivative thereof resulting from reaction of tyrosine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. 3-Methoxytyrosine is one of the main biochemical markers for Aromatic L-amino acid decarboxylase (AADC, EC4.1.1.28) deficiency, an inborn error of metabolism that affects serotonin and dopamine biosynthesis. Chronically high levels of 3-methoxytyrosine are associated with aromatic L-amino acid decarboxylase (AADC, 28) deficiency, an inborn error of metabolism that affects serotonin and dopamine biosynthesis. 3-Methoxytyrosine is a potentially toxic compound. 3-Methoxytyrosine, with regard to humans, has been found to be associated with several diseases such as epilepsy, early-onset, vitamin b6-dependent and pyridoxamine 5-prime-phosphate oxidase deficiency; 3-methoxytyrosine has also been linked to several inborn metabolic disorders including sepiapterin reductase deficiency and aromatic l-amino acid decarboxylase deficiency.
Methylglutaric acid is a leucine metabolite. A large amount of methylglutaric acid is identified in urine of patients with deficiency of 3-methylglutaconyl coenzyme A hydratase (PMID 6181239). Methylglutaric acid is also found to be associated with 3-hydroxy-3-methylglutaryl-CoA lyase deficiency, another inborn error of metabolism.
1-Methylhistamine, also known as H137, belongs to the class of organic compounds known as 2-arylethylamines. These are primary amines that have the general formula RCCNH2, where R is an organic group. 1-Methylhistamine exists in all living organisms, ranging from bacteria to humans. Within humans, 1-methylhistamine participates in a number of enzymatic reactions. In particular, S-adenosylhomocysteine and 1-methylhistamine can be biosynthesized from S-adenosylmethionine and histamine; which is mediated by the enzyme histamine N-methyltransferase. In addition, 1-methylhistamine can be converted into methylimidazole acetaldehyde through its interaction with the enzyme amine oxidase [flavin-containing] a. In humans, 1-methylhistamine is involved in histidine metabolism. 1-Methylhistamine is a potentially toxic compound.
3-Nitrotyrosine, also known as nitrotyrosine is a product of tyrosine nitration mediated by reactive nitrogen species such as peroxynitrite anion and nitrogen dioxide. Nitrotyrosine is identified as an indicator or marker of cell damage, inflammation as well as NO (nitric oxide) production. Nitrotyrosine is formed in the presence of the active metabolite NO. Nitrotyrosine belongs to the class of organic compounds known as tyrosine and derivatives. Tyrosine and derivatives are compounds containing tyrosine or a derivative thereof resulting from reaction of tyrosine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom.
3-Nitrotyrosine, also known as nitrotyrosine is a product of tyrosine nitration mediated by reactive nitrogen species such as peroxynitrite anion and nitrogen dioxide. Nitrotyrosine is identified as an indicator or marker of cell damage, inflammation as well as NO (nitric oxide) production. Nitrotyrosine is formed in the presence of the active metabolite NO. Nitrotyrosine belongs to the class of organic compounds known as tyrosine and derivatives. Tyrosine and derivatives are compounds containing tyrosine or a derivative thereof resulting from reaction of tyrosine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom.
3-Methyluridine is a modified nucleoside of cellular RNA. All modifications are formed post-transcriptionally in RNA from the normal nucleosides by modifying enzymes, especially specific RNA-methyltransferases and RNA-synthetases. Due to the lack of specific phosphorylases for modified nucleosides they cannot be recycled for synthesizing RNA, so they are excreted quantitatively in urine. (PMID 15906010).
3-O-Sulfogalactosylceramide is an acidic, sulfated glycosphingolipid, often known as sulfatide. This lipid occurs in membranes of various cell types, but is found in particularly high concentrations in myelin where it constitutes 3-4% of total membrane lipids. This lipid is synthesized primarily in the oligodendrocytes in the central nervous system. Accumulation of this lipid in the lysosomes is a characteristic of metachromatic leukodystrophy, a lysosomal storage disease caused by the deficiency of arylsulfatase A. Alterations in sulfatide metabolism, trafficking, and homeostasis are present in the earliest clinically recognizable stages of Alzheimer's disease. Cerebrosides are glycosphingolipids. There are four types of glycosphingolipids, the cerebrosides, sulfatides, globosides and gangliosides. Cerebrosides have a single sugar group linked to ceramide. The most common are galactocerebrosides (containing galactose), the least common are glucocerebrosides (containing glucose). Galactocerebrosides are found predominantly in neuronal cell membranes. In contrast glucocerebrosides are not normally found in membranes. Instead, they are typically intermediates in the synthesis or degradation of more complex glycosphingolipids. Galactocerebrosides are synthesized from ceramide and UDP-galactose. Excess lysosomal accumulation of glucocerebrosides is found in Gaucher disease. Sulfatides are glycosphingolipids. There are four types of glycosphingolipids, the cerebrosides, sulfatides, globosides and gangliosides. Sulfatides are the sulfuric acid esters of galactocerebrosides. They are synthesized from galactocerebrosides and activated sulfate, 3'-phosphoadenosine 5'-phosphosulfate (PAPS).
Ureidopropionic acid, also known as 3-ureidopropanoate or N-carbamoyl-beta-alanine, belongs to the class of organic compounds known as ureas. Ureas are compounds containing two amine groups joined by a carbonyl (C=O) functional group. Ureidopropionic acid is an intermediate in the metabolism of uracil. More specifically, it is a breakdown product of dihydrouracil and is produced by the enzyme dihydropyrimidase. It is further decomposed into beta-alanine via the enzyme beta-ureidopropionase. Ureidopropionic acid is essentially a urea derivative of beta-alanine. High levels of ureidopropionic acid are found in individuals with beta-ureidopropionase (UP) deficiency (PMID: 11675655). Enzyme deficiencies in pyrimidine metabolism are associated with a risk for severe toxicity against the antineoplastic agent 5-fluorouracil. Ureidopropionic acid has been detected, but not quantified in, several different foods, such as gram beans, broccoli, climbing beans, oriental wheat, and mandarin orange (clementine, tangerine). This could make ureidopropionic acid a potential biomarker for the consumption of these foods.
Protocatechuic acid, also known as protocatechuate or 3,4-dihydroxybenzoate, belongs to the class of organic compounds known as hydroxybenzoic acid derivatives. Hydroxybenzoic acid derivatives are compounds containing a hydroxybenzoic acid (or a derivative), which is a benzene ring bearing a carboxyl and a hydroxyl groups. The enzyme protocatechuate 3,4-dioxygenase uses 3,4-dihydroxybenzoate and O2 to produce 3-carboxy-cis,cis-muconate. Protocatechuic acid is a drug. In the analogous hardening of the cockroach ootheca, the phenolic substance concerned is protocatechuic acid. Protocatechuic acid is a mild, balsamic, and phenolic tasting compound. Outside of the human body, protocatechuic acid is found, on average, in the highest concentration in a few different foods, such as garden onions, cocoa powders, and star anises and in a lower concentration in lentils, liquors, and red raspberries. Protocatechuic acid has also been detected, but not quantified in several different foods, such as cloud ear fungus, american pokeweeds, common mushrooms, fruits, and feijoa. This could make protocatechuic acid a potential biomarker for the consumption of these foods. It is also found in Allium cepa (17,540 ppm). It is a major metabolite of antioxidant polyphenols found in green tea. Similarly, PCA was reported to increase proliferation and inhibit apoptosis of neural stem cells. In vitro testing documented antioxidant and anti-inflammatory activity of PCA, while liver protection in vivo was measured by chemical markers and histological assessment.
Dephospho-CoA, also known as 3'-dephospho-CoA, belongs to the class of organic compounds known as purine ribonucleoside diphosphates. These are purine ribonucleosides with a diphosphate group linked to the ribose moiety. Thus, dephospho-CoA is considered to be a fatty ester lipid molecule. Dephospho-CoA is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Outside of the human body, dephospho-CoA has been detected, but not quantified in, several different foods, such as wild leeks, summer savouries, arctic blackberries, biscuits, and persimmons. This could make dephospho-CoA a potential biomarker for the consumption of these foods. Dephospho-CoA is an intermediate in pantothenate and CoA biosynthesis. It is a substrate for bifunctional coenzyme A synthase which contains the dephospho-CoA kinase (EC 2.7.1.24). This enzyme catalyzes the final step in CoA biosynthesis: the phosphorylation of the 3'-hydroxyl group of ribose using ATP as a phosphate donor. The reaction is ATP + 3'-dephospho-CoA = ADP + CoA.
Cyclic AMP (cAMP) or cyclic adenosine monophosphate is an adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. cAMP is found in all organisms ranging from bacteria to plants to animals. In humans and other mammals it is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon and ACTH. cAMP is synthesized from ATP by adenylate cyclase. Adenylate cyclase is located at the inner side of cell membranes. Adenylate cyclase is activated by the hormones glucagon and adrenaline and by G protein. Liver adenylate cyclase responds more strongly to glucagon, and muscle adenylate cyclase responds more strongly to adrenaline. cAMP decomposition into AMP is catalyzed by the enzyme phosphodiesterase. cAMP is primarily used for intracellular signal transduction, such as transferring into cells the effects of hormones like glucagon and adrenaline, which cannot pass through the plasma membrane. cAMP is also involved in the activation of protein kinases. In addition, cAMP binds to and regulates the function of ion channels such as the HCN channels. Hyperpolarization-activated cyclic nucleotide‚Äìgated (HCN) channels are integral membrane proteins that serve as nonselective voltage-gated cation channels in the plasma membranes of heart and brain cells. HCN channels are sometimes referred to as pacemaker channels because they help to generate rhythmic activity within groups of heart and brain cells.
4-Acetamidobutanoic acid, also known as 4-acetamidobutanoate or N-acetyl-4-aminobutyric acid, is a member of the class of compounds known as gamma amino acids and derivatives. These compounds are amino acids having an -NH2 group attached to the gamma carbon atom. 4-Acetamidobutanoic acid is soluble in water. 4-Acetamidobutanoic acid can be found in a number of food items such as Rubus species (blackberry, raspberry), cassava, pepper (Capsicum frutescens), and napa cabbage, which makes 4-acetamidobutanoic acid a potential biomarker for the consumption of these food products. 4-Acetamidobutanoic acid can be found in blood, feces, and urine, as well as in human prostate tissue. 4-Acetamidobutanoic acid exists in all eukaryotes, ranging from yeast to humans. 4-Acetamidobutanoic acid is a GABA derivative, a product of the urea cycle and the metabolism of amino groups, and the product of NAD-linked aldehyde dehydrogenase (EC 1.2.1.3) (KEGG).
4-Guanidinobutanoic acid, also known as gamma-guanidinobutyrate or 4-(carbamimidamido)butanoate, belongs to the class of organic compounds known as gamma amino acids and derivatives. These are amino acids having a (-NH2) group attached to the gamma carbon atom. 4-Guanidinobutanoic acid is a normal metabolite present in low concentrations. 4-Guanidinobutanoic acid exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, 4-Guanidinobutanoic acid has been detected, but not quantified in a few different foods, such as apples, french plantains, and loquats. This could make 4-guanidinobutanoic acid a potential biomarker for the consumption of these foods. Patients with hyperargininemia have an arginase deficiency which leads to blockade of the urea cycle in the last step with several clinical symptoms. Owing to the arginase deficiency this patients accumulate arginine which leads eventually to epileptogenic guanidino compounds (PMID 7752905).
4-Guanidinobutanoic acid, also known as gamma-guanidinobutyrate or 4-(carbamimidamido)butanoate, belongs to the class of organic compounds known as gamma amino acids and derivatives. These are amino acids having a (-NH2) group attached to the gamma carbon atom. 4-Guanidinobutanoic acid is a normal metabolite present in low concentrations. 4-Guanidinobutanoic acid exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, 4-Guanidinobutanoic acid has been detected, but not quantified in a few different foods, such as apples, french plantains, and loquats. This could make 4-guanidinobutanoic acid a potential biomarker for the consumption of these foods. Patients with hyperargininemia have an arginase deficiency which leads to blockade of the urea cycle in the last step with several clinical symptoms. Owing to the arginase deficiency this patients accumulate arginine which leads eventually to epileptogenic guanidino compounds (PMID 7752905).
4-Hydroxy-2-ketoglutaric acid is a substrate for Fructose-bisphosphate aldolase A.
4-Hydroxyphenylpyruvic acid (4-HPPA) is a keto acid that is involved in the tyrosine catabolism pathway. It is a product of the enzyme (R)-4-hydroxyphenyllactate dehydrogenase (EC 1.1.1.222) and is formed during tyrosine metabolism. The conversion from tyrosine to 4-HPPA is catalyzed by tyrosine aminotransferase. Additionally, 4-HPPA can be converted to homogentisic acid which is one of the precursors to ochronotic pigment. The enzyme 4-hydroxyphenylpyruvic acid dioxygenase (HPD) catalyzes the reaction that converts 4-hydroxyphenylpyruvic acid to homogentisic acid. A deficiency in the catalytic activity of HPD is known to lead to tyrosinemia type III, an autosomal recessive disorder characterized by elevated levels of blood tyrosine and massive excretion of tyrosine derivatives into urine. It has been shown that hawkinsinuria, an autosomal dominant disorder characterized by the excretion of 'hawkinsin,' may also be a result of HPD deficiency (PMID: 11073718). Moreover, 4-hydroxyphenylpyruvic acid is also found to be associated in phenylketonuria, which is also an inborn error of metabolism. There are two isomers of HPPA, specifically 4HPPA and 3HPPA, of which 4HPPA is the most common. 4-HPPA has been found to be a microbial metabolite in Escherichia (ECMDB).
4-Hydroxyproline (hydroxyproline or Hyp) is a major component of the protein collagen. Hydroxyproline is produced by hydroxylation of the amino acid proline and is, therefore, a post-translationally modified, non-essential amino acid. Hydroxyproline and proline play key roles in collagen stability. In particular, they permit the sharp twisting of the collagen helix. Hydroxyproline is found in few proteins other than collagen. The only other mammalian protein which includes hydroxyproline is elastin. For this reason, hydroxyproline content has been used as an indicator to determine collagen and/or gelatin amount in tissue or biological samples. Increased serum and urine levels of hydroxyproline have been found in Paget's disease (PMID: 436278). Hydroxyproline (Hyp) content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption or tissue degradation. Bedridden and elderly individuals show significantly elevated serum levels of hydroxyproline in comparison to normal, active individuals (PMID: 10706420). Elevated levels of urinary hydroxyproline are also indicative of muscle damage (PMID: 21988268). Increased reactive oxygen species (ROS) are also known to accelerate collagen degradation. Hydroxyproline levels increase in cases of depression and stress (PMID: 21483218). 4-Hydroxyproline is found to be associated with Alzheimer's disease, and also hydroxyprolinemia and iminoglycinuria which are both inborn errors of metabolism. 4-Hydroxyproline is also involved in metabolic disorders such as hyperprolinemia type I, hyperornithinemia with gyrate atrophy (HOGA), L-arginine:glycine amidinotransferase deficiency, creatine deficiency, and guanidinoacetate methyltransferase deficiency. A deficiency in ascorbic acid can result in impaired hydroxyproline formation (PubChem). trans-4-Hydroxy-L-proline is a biomarker for the consumption of processed meat.
4-Hydroxyproline (hydroxyproline or Hyp) is a major component of the protein collagen. Hydroxyproline is produced by hydroxylation of the amino acid proline and is, therefore, a post-translationally modified, non-essential amino acid. Hydroxyproline and proline play key roles in collagen stability. In particular, they permit the sharp twisting of the collagen helix. Hydroxyproline is found in few proteins other than collagen. The only other mammalian protein which includes hydroxyproline is elastin. For this reason, hydroxyproline content has been used as an indicator to determine collagen and/or gelatin amount in tissue or biological samples. Increased serum and urine levels of hydroxyproline have been found in Paget's disease (PMID: 436278). Hydroxyproline (Hyp) content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption or tissue degradation. Bedridden and elderly individuals show significantly elevated serum levels of hydroxyproline in comparison to normal, active individuals (PMID: 10706420). Elevated levels of urinary hydroxyproline are also indicative of muscle damage (PMID: 21988268). Increased reactive oxygen species (ROS) are also known to accelerate collagen degradation. Hydroxyproline levels increase in cases of depression and stress (PMID: 21483218). 4-Hydroxyproline is found to be associated with Alzheimer's disease, and also hydroxyprolinemia and iminoglycinuria which are both inborn errors of metabolism. 4-Hydroxyproline is also involved in metabolic disorders such as hyperprolinemia type I, hyperornithinemia with gyrate atrophy (HOGA), L-arginine:glycine amidinotransferase deficiency, creatine deficiency, and guanidinoacetate methyltransferase deficiency. A deficiency in ascorbic acid can result in impaired hydroxyproline formation (PubChem). trans-4-Hydroxy-L-proline is a biomarker for the consumption of processed meat.
Imidazol-4-ylacetic acid is a monocarboxylic acid that is acetic acid in which one of the methyl hydrogens has been replaced by an imidazol-4-yl group. It has a role as a mouse metabolite. It is a monocarboxylic acid and a member of imidazoles. It derives from an acetic acid. It is a conjugate acid of an imidazol-4-ylacetate. It is a tautomer of an imidazol-5-ylacetic acid and a 2H-imidazol-4-ylacetic acid. Imidazoleacetic acid, also known as 4(5)-imidazoleacetate or IAA, belongs to the class of organic compounds known as imidazolyl carboxylic acids and derivatives. These are organic compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an imidazole ring. Imidazoleacetic acid exists in all living organisms, ranging from bacteria to humans. imidazoleacetic acid can be biosynthesized from imidazole-4-acetaldehyde through its interaction with the enzyme aldehyde dehydrogenase, mitochondrial. In humans, imidazoleacetic acid is involved in histidine metabolism. Outside of the human body, Imidazoleacetic acid has been detected, but not quantified in several different foods, such as chinese cinnamons, jostaberries, vanilla, butternut squash, and red rices. Imidazoleacetic acid is a potentially toxic compound. Imidazoleacetic acid is a metabolite product of Histamine metabolism.
4-Pyridoxic acid is a member of the class of compounds known as methylpyridines. More specifically it is a 2-methylpyridine derivative substituted by a hydroxy group at C-3, a carboxy group at C-4, and a hydroxymethyl group at C-5. 4-Pyridoxic acid is the catabolic product of vitamin B6 (also known as pyridoxine, pyridoxal and pyradoxamine) and is excreted in the urine. Urinary levels of 4-pyridoxic acid are lower in females than in males and will be reduced even further in persons with a riboflavin deficiency. 4-Pyridoxic acid is formed by the action of aldehyde oxidase I (an endogenous enzyme) and by microbial enzymes (pyridoxal 4-dehydrogenase), an NAD-dependent aldehyde dehydrogenase. 4-pyridoxic acid can be further broken down by the gut microflora via the enzyme known as 4-pyridoxic acid dehydrogenase. This enzyme catalyzes the four-electron oxidation of 4-pyridoxic acid to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate, using nicotinamide adenine dinucleotide (NAD) as a cofactor.
4-Pyridoxic acid is a member of the class of compounds known as methylpyridines. More specifically it is a 2-methylpyridine derivative substituted by a hydroxy group at C-3, a carboxy group at C-4, and a hydroxymethyl group at C-5. 4-Pyridoxic acid is the catabolic product of vitamin B6 (also known as pyridoxine, pyridoxal and pyradoxamine) and is excreted in the urine. Urinary levels of 4-pyridoxic acid are lower in females than in males and will be reduced even further in persons with a riboflavin deficiency. 4-Pyridoxic acid is formed by the action of aldehyde oxidase I (an endogenous enzyme) and by microbial enzymes (pyridoxal 4-dehydrogenase), an NAD-dependent aldehyde dehydrogenase. 4-pyridoxic acid can be further broken down by the gut microflora via the enzyme known as 4-pyridoxic acid dehydrogenase. This enzyme catalyzes the four-electron oxidation of 4-pyridoxic acid to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate, using nicotinamide adenine dinucleotide (NAD) as a cofactor.
4-Pyridoxic acid is a member of the class of compounds known as methylpyridines. More specifically it is a 2-methylpyridine derivative substituted by a hydroxy group at C-3, a carboxy group at C-4, and a hydroxymethyl group at C-5. 4-Pyridoxic acid is the catabolic product of vitamin B6 (also known as pyridoxine, pyridoxal and pyradoxamine) and is excreted in the urine. Urinary levels of 4-pyridoxic acid are lower in females than in males and will be reduced even further in persons with a riboflavin deficiency. 4-Pyridoxic acid is formed by the action of aldehyde oxidase I (an endogenous enzyme) and by microbial enzymes (pyridoxal 4-dehydrogenase), an NAD-dependent aldehyde dehydrogenase. 4-pyridoxic acid can be further broken down by the gut microflora via the enzyme known as 4-pyridoxic acid dehydrogenase. This enzyme catalyzes the four-electron oxidation of 4-pyridoxic acid to 3-hydroxy-2-methylpyridine-4,5-dicarboxylate, using nicotinamide adenine dinucleotide (NAD) as a cofactor.
Fapy-adenine is an oxidized DNA base. Oxidized nucleosides are biochemical markers for tumors, aging, and neurodegenerative diseases (PMID 15116424). Oxidative stress damage to DNA bases may contribute to neuronal loss in Alzheimer's disease (AD). Increased levels were observed in parietal, temporal, occipital, and frontal lobe, superior temporal gyrus, and hippocampus areas of the brain in patients with AD. (PMID 9109533).
5-Hydroxymethyluracil (5hmU), also known as alpha-hydroxythymine, belongs to the class of organic compounds known as pyrimidones. Pyrimidones are compounds that contain a pyrimidine ring, which bears a ketone. Pyrimidine is a 6-membered ring consisting of four carbon atoms and two nitrogen centers at the 1- and 3- ring positions. 5hmU has been identified as a thymine base modification found in the genomes of a diverse range of organisms (PMID: 28137275). 5-hydroxymethyluracil has been detected in bacteriophages, dinoflagellates, leishmania, and in eukaryotic genomes where its level appears to be cell type-specific. 5-Hydroxymethyluracil  arises from the oxidation of thymine.  5-Hydroxymethyluracil is produced by the enzyme thymine dioxygenase (EC 1.14.11.6) which catalyzes the chemical reaction thymine + 2-oxoglutarate + O2 <->  5-hydroxymethyluracil + succinate + CO2. The 3 substrates of this enzyme are thymine, 2-oxoglutarate, and O2, whereas its 3 products are 5-hydroxymethyluracil, succinate, and CO2. The 5hmU base can also be generated by oxidation/hydroxylation of thymine by the Ten-Eleven-Translocation (TET) proteins or result from deamination of 5hmC (PMID: 29184924). DNA containing 5hmU has been reported to be more flexible and hydrophilic (PMID: 29184924).
5-Acetylamino-6-amino-3-methyluracil (AAMU) is one of caffeine major metabolites. Analysis of caffeine and its metabolites is of interest with respect to caffeine exposure, for kinetic and metabolism studies and for opportunistic in vivo estimation of drug metabolizing enzyme activity in humans and animals. Urinary caffeine metabolite ratios are used in humans to assess the activity of cytochrome P450 1A2 (CYP1A2), xanthine oxidase and N-acetyltransferase 2 (NAT2), which are involved in the activation or detoxification of various xenobiotic compounds, including carcinogens. Investigating the activity of these enzymes is of clinical relevance for assessing intra- and inter-individual differences in NAT2- and CYP1A2-mediated drug metabolism, and for evaluating the risk of developing specific exposure-related diseases. (PMID: 3506820, 15685651, 12534641).
5-Acetylamino-6-amino-3-methyluracil (AAMU) is one of caffeine major metabolites. Analysis of caffeine and its metabolites is of interest with respect to caffeine exposure, for kinetic and metabolism studies and for opportunistic in vivo estimation of drug metabolizing enzyme activity in humans and animals. Urinary caffeine metabolite ratios are used in humans to assess the activity of cytochrome P450 1A2 (CYP1A2), xanthine oxidase and N-acetyltransferase 2 (NAT2), which are involved in the activation or detoxification of various xenobiotic compounds, including carcinogens. Investigating the activity of these enzymes is of clinical relevance for assessing intra- and inter-individual differences in NAT2- and CYP1A2-mediated drug metabolism, and for evaluating the risk of developing specific exposure-related diseases. (PMID: 3506820, 15685651, 12534641).
5-Acetylamino-6-amino-3-methyluracil (AAMU) is one of caffeine major metabolites. Analysis of caffeine and its metabolites is of interest with respect to caffeine exposure, for kinetic and metabolism studies and for opportunistic in vivo estimation of drug metabolizing enzyme activity in humans and animals. Urinary caffeine metabolite ratios are used in humans to assess the activity of cytochrome P450 1A2 (CYP1A2), xanthine oxidase and N-acetyltransferase 2 (NAT2), which are involved in the activation or detoxification of various xenobiotic compounds, including carcinogens. Investigating the activity of these enzymes is of clinical relevance for assessing intra- and inter-individual differences in NAT2- and CYP1A2-mediated drug metabolism, and for evaluating the risk of developing specific exposure-related diseases. (PMID: 3506820, 15685651, 12534641).
5-Acetylamino-6-amino-3-methyluracil (AAMU) is one of caffeine major metabolites. Analysis of caffeine and its metabolites is of interest with respect to caffeine exposure, for kinetic and metabolism studies and for opportunistic in vivo estimation of drug metabolizing enzyme activity in humans and animals. Urinary caffeine metabolite ratios are used in humans to assess the activity of cytochrome P450 1A2 (CYP1A2), xanthine oxidase and N-acetyltransferase 2 (NAT2), which are involved in the activation or detoxification of various xenobiotic compounds, including carcinogens. Investigating the activity of these enzymes is of clinical relevance for assessing intra- and inter-individual differences in NAT2- and CYP1A2-mediated drug metabolism, and for evaluating the risk of developing specific exposure-related diseases. (PMID: 3506820, 15685651, 12534641).
5-Aminolevulinic acid, also known as 5-aminolevulinate or 5-amino-4-oxopentanoate, belongs to the class of organic compounds known as delta amino acids and derivatives. Delta amino acids and derivatives are compounds containing a carboxylic acid group and an amino group at the C5 carbon atom. 5-Aminolevulinic acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. 5-Aminolevulinic acid exists in all living species, ranging from bacteria to humans. 5-aminolevulinic acid can be biosynthesized from glycine and succinyl-CoA by the enzyme 5-aminolevulinate synthase. The simplest delta-amino acid in which the hydrogens at the gamma position are replaced by an oxo group. In humans, 5-aminolevulinic acid is involved in the metabolic disorder called the dimethylglycine dehydrogenase deficiency pathway. Outside of the human body, 5-Aminolevulinic acid has been detected, but not quantified in several different foods, such as american butterfish, vaccinium (blueberry, cranberry, huckleberry), amaranths, purple mangosteens, and garden cress. Used (in the form of the hydrochloride salt) in combination with blue light illumination for the treatment of minimally to moderately thick actinic keratosis of the face or scalp. It is metabolised to protoporphyrin IX, a photoactive compound which accumulates in the skin.
5-Hydroxyindoleacetic acid, also known as 5-hydroxyindole-3-acetate or 5-HIAA, belongs to the class of organic compounds known as indole-3-acetic acid derivatives. Indole-3-acetic acid derivatives are compounds containing an acetic acid (or a derivative) linked to the C3 carbon atom of an indole. 5-Hydroxyindoleacetic acid exists in all living organisms, ranging from bacteria to humans. In humans, 5-hydroxyindoleacetic acid is a breakdown product of serotonin that is excreted in the urine and it also participates in a number of enzymatic reactions. 5-hydroxyindoleacetic acid can be biosynthesized from 5-hydroxyindoleacetaldehyde; which is catalyzed by the mitochondrial enzyme aldehyde dehydrogenase. In addition, 5-hydroxyindoleacetic acid and S-adenosylmethionine can be converted into 5-methoxyindoleacetate and S-adenosylhomocysteine through its interaction with the enzyme acetylserotonin O-methyltransferase. 5-Hydroxyindoleacetic acid is also involved in the metabolism of tryptophan. 5-Hydroxyindoleacetic acid has been found to be associated with several human diseases such as brunner syndrome, friedreich's ataxia, schizophrenia, and olivopontocerebral atrophy; 5-hydroxyindoleacetic acid has also been linked to the inborn metabolic disorder sepiapterin reductase deficiency. Elevated levels of 5-hydroxyindoleacetic acid in urine (>20 uM) are indicative of appendicitis and gastroenteritis (PMID: 11462886). Serotonin and 5-Hydroxyindoleacetic acid are produced in excess amounts by carcinoid tumors, and levels of these substances may be measured in the urine to test for carcinoid tumors (NCI). 5-Hydroxyindoleacetic acid has also been found to be a product of human gut microbiota.
5-Hydroxyindoleacetic acid, also known as 5-hydroxyindole-3-acetate or 5-HIAA, belongs to the class of organic compounds known as indole-3-acetic acid derivatives. Indole-3-acetic acid derivatives are compounds containing an acetic acid (or a derivative) linked to the C3 carbon atom of an indole. 5-Hydroxyindoleacetic acid exists in all living organisms, ranging from bacteria to humans. In humans, 5-hydroxyindoleacetic acid is a breakdown product of serotonin that is excreted in the urine and it also participates in a number of enzymatic reactions. 5-hydroxyindoleacetic acid can be biosynthesized from 5-hydroxyindoleacetaldehyde; which is catalyzed by the mitochondrial enzyme aldehyde dehydrogenase. In addition, 5-hydroxyindoleacetic acid and S-adenosylmethionine can be converted into 5-methoxyindoleacetate and S-adenosylhomocysteine through its interaction with the enzyme acetylserotonin O-methyltransferase. 5-Hydroxyindoleacetic acid is also involved in the metabolism of tryptophan. 5-Hydroxyindoleacetic acid has been found to be associated with several human diseases such as brunner syndrome, friedreich's ataxia, schizophrenia, and olivopontocerebral atrophy; 5-hydroxyindoleacetic acid has also been linked to the inborn metabolic disorder sepiapterin reductase deficiency. Elevated levels of 5-hydroxyindoleacetic acid in urine (>20 uM) are indicative of appendicitis and gastroenteritis (PMID: 11462886). Serotonin and 5-Hydroxyindoleacetic acid are produced in excess amounts by carcinoid tumors, and levels of these substances may be measured in the urine to test for carcinoid tumors (NCI). 5-Hydroxyindoleacetic acid has also been found to be a product of human gut microbiota.
5-Hydroxyindoleacetic acid, also known as 5-hydroxyindole-3-acetate or 5-HIAA, belongs to the class of organic compounds known as indole-3-acetic acid derivatives. Indole-3-acetic acid derivatives are compounds containing an acetic acid (or a derivative) linked to the C3 carbon atom of an indole. 5-Hydroxyindoleacetic acid exists in all living organisms, ranging from bacteria to humans. In humans, 5-hydroxyindoleacetic acid is a breakdown product of serotonin that is excreted in the urine and it also participates in a number of enzymatic reactions. 5-hydroxyindoleacetic acid can be biosynthesized from 5-hydroxyindoleacetaldehyde; which is catalyzed by the mitochondrial enzyme aldehyde dehydrogenase. In addition, 5-hydroxyindoleacetic acid and S-adenosylmethionine can be converted into 5-methoxyindoleacetate and S-adenosylhomocysteine through its interaction with the enzyme acetylserotonin O-methyltransferase. 5-Hydroxyindoleacetic acid is also involved in the metabolism of tryptophan. 5-Hydroxyindoleacetic acid has been found to be associated with several human diseases such as brunner syndrome, friedreich's ataxia, schizophrenia, and olivopontocerebral atrophy; 5-hydroxyindoleacetic acid has also been linked to the inborn metabolic disorder sepiapterin reductase deficiency. Elevated levels of 5-hydroxyindoleacetic acid in urine (>20 uM) are indicative of appendicitis and gastroenteritis (PMID: 11462886). Serotonin and 5-Hydroxyindoleacetic acid are produced in excess amounts by carcinoid tumors, and levels of these substances may be measured in the urine to test for carcinoid tumors (NCI). 5-Hydroxyindoleacetic acid has also been found to be a product of human gut microbiota.
5-Hydroxymethyl-6-methyl- 2,4-(1H,3H)-pyrimidinedione. Uracil derivative used in combination with toxic antibiotics to lessen their toxicity; also to stimulate leukopoiesis and immunity.
5-methoxysalicylic acid is a methoxysalicylic acid that is salicylic acid which is carrying a methoxy group at position 5. It has a role as a bacterial metabolite and a human urinary metabolite. 5-Methoxysalicylic acid is also known as 2-hydroxy-5-methoxybenzoate or 5-methoxy-2-hydroxybenzoate and belongs to the class of organic compounds known as m-methoxybenzoic acids and derivatives. These are benzoic acids in which the hydrogen atom at position 3 of the benzene ring is replaced by a methoxy group. Outside of the human body, 5-Methoxysalicylic acid has been detected, but not quantified in herbs and spices and tea.
5-methoxysalicylic acid is a methoxysalicylic acid that is salicylic acid which is carrying a methoxy group at position 5. It has a role as a bacterial metabolite and a human urinary metabolite. 5-Methoxysalicylic acid is also known as 2-hydroxy-5-methoxybenzoate or 5-methoxy-2-hydroxybenzoate and belongs to the class of organic compounds known as m-methoxybenzoic acids and derivatives. These are benzoic acids in which the hydrogen atom at position 3 of the benzene ring is replaced by a methoxy group. Outside of the human body, 5-Methoxysalicylic acid has been detected, but not quantified in herbs and spices and tea.
5-Methylcytidine belongs to the class of organic compounds known as pyrimidine nucleosides. Pyrimidine nucleosides are compounds comprising a pyrimidine base attached to a ribosyl or deoxyribosyl moiety.
Ribothymidine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID:3506820, 17044778, 17264127, 16799933).
Ribothymidine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID:3506820, 17044778, 17264127, 16799933).
Ribothymidine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID:3506820, 17044778, 17264127, 16799933).
5-Thymidylic acid (conjugate base thymidylate), also known as thymidine monophosphate (TMP), deoxythymidine monophosphate (dTMP), or deoxythymidylic acid (conjugate base deoxythymidylate), is a nucleotide that is used as a monomer in DNA. It is an ester of phosphoric acid with the nucleoside thymidine. dTMP consists of a phosphate group, the pentose sugar deoxyribose, and the nucleobase thymine. Unlike the other deoxyribonucleotides, thymidine monophosphate often does not contain the "deoxy" prefix in its name; nevertheless, its symbol often includes a "d" ("dTMP"). 5-Thymidylic acid belongs to the class of organic compounds known as pyrimidine 2'-deoxyribonucleoside monophosphates. These are pyrimidine nucleotides with a monophosphate group linked to the ribose moiety lacking a hydroxyl group at position 2. The neutral species of 5-Thymidylic acid (2'-deoxythymidine 5'-monophosphate). 5-Thymidylic acid exists in all living species, ranging from bacteria to humans. Within humans, 5-thymidylic acid participates in a number of enzymatic reactions. In particular, 5-thymidylic acid and dihydrofolic acid can be biosynthesized from dUMP and 5,10-methylene-THF by the enzyme thymidylate synthase. In addition, 5-thymidylic acid can be converted into dTDP; which is catalyzed by the enzyme thymidylate synthase. In humans, 5-thymidylic acid is involved in pyrimidine metabolism. Outside of the human body, 5-Thymidylic acid has been detected, but not quantified in several different foods, such as common buckwheats, corn salad, garden cress, squashberries, and star fruits.
Dalbergioidin is found in adzuki bean. Dalbergioidin is isolated from Dolichos biflorus (papadi), Lablab niger (hyacinth bean) and Phaseolus vulgaris (kidney bean
5'-Methylthioadenosine, also known as MTA or thiomethyladenosine, belongs to the class of organic compounds known as 5'-deoxy-5'-thionucleosides. These are 5'-deoxyribonucleosides in which the ribose is thio-substituted at the 5'position by a S-alkyl group. 5'-Methylthioadenosine is metabolized solely by MTA-phosphorylase, to yield 5-methylthioribose-1-phosphate and adenine, a crucial step in the methionine and purine salvage pathways, respectively. 5'-Methylthioadenosine exists in all living species, ranging from bacteria to humans. 5'-Methylthioadenosine (MTA) is a naturally occurring sulfur-containing nucleoside present in all mammalian tissues. Within humans, 5'-methylthioadenosine participates in a number of enzymatic reactions. In particular, 5'-methylthioadenosine and spermidine can be biosynthesized from S-adenosylmethioninamine and putrescine through the action of the enzyme spermidine synthase. In addition, 5'-methylthioadenosine can be converted into 5-methylthioribose 1-phosphate and L-methionine; which is catalyzed by the enzyme S-methyl-5'-thioadenosine phosphorylase. It is produced from S-adenosylmethionine mainly through the polyamine biosynthetic pathway, where it behaves as a powerful inhibitory product. For instance, 5'-Methylthioadenosine has been shown to influence the regulation of gene expression, proliferation, differentiation, and apoptosis (PMID:15313459). In humans, 5'-methylthioadenosine is involved in the metabolic disorder called hypermethioninemia. Outside of the human body, 5'-Methylthioadenosine has been detected, but not quantified in several different foods, such as soursops, allspices, summer grapes, alaska wild rhubarbs, and breadfruits. Elevated excretion appears in children with severe combined immunodeficiency syndrome (SCID) (PMID:3987052). Evidence suggests that 5'-Methylthioadenosine can affect cellular processes in many ways. 5'-Methylthioadenosine can be found in human urine.
6-(alpha-D-Glucosaminyl)-1D-myo-inositol is a cleavage product of glycosylphosphatidylinositol phospholipase D. This enzyme catalyzes the following reaction: 6-(alpha-D-glucosaminyl)-1-phosphatidyl-1D-myo-inositol + H2O =. 6-(alpha-D-glucosaminyl)-1D-myo-inositol + 3-sn-phosphatidate.
7-Methyladenine is part of the base excision repair pathway. In this pathway, alkylated DNA is hydrolysed via the enzyme DNA-3-methyladenine glycosylase II (EC 3.2.2.21), releasing 3-methyladenine, 3-methylguanine, 7-methylguanine and 7-methyladenine. This enzyme is responsible for the hydrolysis of the deoxyribose N-glycosidic bond to excise 3-methyladenine, and 7-methylguanine from the damaged DNA polymer formed by alkylation lesions. Base excision repair (BER) is a cellular mechanism that repairs damaged DNA throughout the cell cycle. Repairing DNA sequence errors is necessary so that mutations are not propagated or to remove lesions that may lead to breaks in the DNA during replication. Single bases in DNA can be chemically mutated, for example by deamination or alkylation, resulting in incorrect base-pairing, and consequently, mutations in the DNA. Base excision repair involves flipping the mutated base out of the DNA helix and repairing the base alone. There are two main enzymes used, DNA glycosylases and AP endonucleases. The DNA glycosylase is used to break the beta-N glycosidic bond to create an AP site. AP endonuclease recognizes this site and nicks the damaged DNA on the 5' side (upstream) of the AP site creating a free 3'-OH. DNA polymerase, Pol I (human pol beta), extends the DNA from the free 3'-OH using its exonuclease activity to replace the nucleotide of the damaged base, as well as a few downstream, followed by sealing of the new DNA strand by DNA ligase. In mammalian cells, this is done by LigIII in complex with the scaffold protein XRCC1. Usually, BER is divided into short-patch repair (where a single nucleotide is replaced) or long-patch repair (where 2-10 nucleotides are replaced). Mammalian long-patch repair includes PCNA and pol delta/epsilon for nucleotide resynthesis, FEN1 to cut of the 'flap' including the damaged base, and LigI.
7-Methylguanine is a metabolite of DNA methylation and depurination observed in normal human biofluids; however, it has been found significantly higher in the urine of smokers than in nonsmokers. (PMID 16059882). 7-Methylguanine has been identified in the human placenta (PMID: 32033212).
2-Methylguanosine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID: 17336316, 17154124, 3506820, 17044778, 17264127).
8-hydroxy-deoxyguanosine (8-OHdG) is a sensitive marker of the DNA damage due to hydroxyl radical attack at the C8 of guanine. This damage, if left unrepaired, has been proposed to contribute to mutagenicity and cancer promotion. 8-OHdG has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
8-hydroxy-deoxyguanosine (8-OHdG) is a sensitive marker of the DNA damage due to hydroxyl radical attack at the C8 of guanine. This damage, if left unrepaired, has been proposed to contribute to mutagenicity and cancer promotion. 8-OHdG has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
Formation of 8-hydroxyguanine (8-OHG), a mutagenic base which is a marker for OH-mediated DNA damage, requires peroxidase and halides and occurs in the presence of transition metal chelators (DTPA +/- desferrioxamine), and is inhibited by catalase, superoxide dismutase (SOD), and scavengers of hypohalous acids. (PMID 10820020). 8-Hydroxyguanine is an oxidative stress marker for diagnosis of Alzheimer's disease (AD). (PMID 15977989).
N-Acetylcarnosine (NAC) is a naturally-occurring compound chemically related to the dipeptide carnosine. Its molecular structure is similar to carnosine with the exception that it carries an additional acetyl group. This makes NAC a more stable molecule which is not easily destroyed by carnosinase, an enzyme that breaks down carnosine to its constituent amino acids, beta-alanine and histidine. NAC is a free-radical scavenger and is particularly active against lipid peroxidation in the different parts of the lens in the eye. It is the active ingredient of eye drops used in order to prevent or treat cataract.
N-Acetylcarnosine (NAC) is a naturally-occurring compound chemically related to the dipeptide carnosine. Its molecular structure is similar to carnosine with the exception that it carries an additional acetyl group. This makes NAC a more stable molecule which is not easily destroyed by carnosinase, an enzyme that breaks down carnosine to its constituent amino acids, beta-alanine and histidine. NAC is a free-radical scavenger and is particularly active against lipid peroxidation in the different parts of the lens in the eye. It is the active ingredient of eye drops used in order to prevent or treat cataract.
Adenosine is a nucleoside that is composed of adenine and D-ribose. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. For instance, adenosine plays an important role in energy transfer as adenosine triphosphate (ATP) and adenosine diphosphate (ADP). It also plays a role in signal transduction as cyclic adenosine monophosphate (cAMP). Adenosine itself is both a neurotransmitter and potent vasodilator. When administered intravenously adenosine causes transient heart block in the AV node. Due to the effects of adenosine on AV node-dependent supraventricular tachycardia, adenosine is considered a class V antiarrhythmic agent. Overdoses of adenosine intake (as a drug) can lead to several side effects including chest pain, feeling faint, shortness of breath, and tingling of the senses. Serious side effects include a worsening dysrhythmia and low blood pressure. When present in sufficiently high levels, adenosine can act as an immunotoxin and a metabotoxin. An immunotoxin disrupts, limits the function, or destroys immune cells. A metabotoxin is an endogenous metabolite that causes adverse health effects at chronically high levels. Chronically high levels of adenosine are associated with adenosine deaminase deficiency. Adenosine is a precursor to deoxyadenosine, which is a precursor to dATP. A buildup of dATP in cells inhibits ribonucleotide reductase and prevents DNA synthesis, so cells are unable to divide. Since developing T cells and B cells are some of the most mitotically active cells, they are unable to divide and propagate to respond to immune challenges. High levels of deoxyadenosine also lead to an increase in S-adenosylhomocysteine, which is toxic to immature lymphocytes.
Adenosine is a nucleoside that is composed of adenine and D-ribose. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. For instance, adenosine plays an important role in energy transfer as adenosine triphosphate (ATP) and adenosine diphosphate (ADP). It also plays a role in signal transduction as cyclic adenosine monophosphate (cAMP). Adenosine itself is both a neurotransmitter and potent vasodilator. When administered intravenously adenosine causes transient heart block in the AV node. Due to the effects of adenosine on AV node-dependent supraventricular tachycardia, adenosine is considered a class V antiarrhythmic agent. Overdoses of adenosine intake (as a drug) can lead to several side effects including chest pain, feeling faint, shortness of breath, and tingling of the senses. Serious side effects include a worsening dysrhythmia and low blood pressure. When present in sufficiently high levels, adenosine can act as an immunotoxin and a metabotoxin. An immunotoxin disrupts, limits the function, or destroys immune cells. A metabotoxin is an endogenous metabolite that causes adverse health effects at chronically high levels. Chronically high levels of adenosine are associated with adenosine deaminase deficiency. Adenosine is a precursor to deoxyadenosine, which is a precursor to dATP. A buildup of dATP in cells inhibits ribonucleotide reductase and prevents DNA synthesis, so cells are unable to divide. Since developing T cells and B cells are some of the most mitotically active cells, they are unable to divide and propagate to respond to immune challenges. High levels of deoxyadenosine also lead to an increase in S-adenosylhomocysteine, which is toxic to immature lymphocytes.
Adenosine monophosphate, also known as 5'-adenylic acid and abbreviated AMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. AMP consists of the phosphate group, the pentose sugar ribose, and the nucleobase adenine. AMP can be produced during ATP synthesis by the enzyme adenylate kinase. AMP has recently been approved as a 'Bitter Blocker' additive to foodstuffs. When AMP is added to bitter foods or foods with a bitter aftertaste it makes them seem 'sweeter'. This potentially makes lower calorie food products more palatable.
Adenosine triphosphate (ATP) is a nucleotide consisting of a purine base (adenine) attached to the first carbon atom of ribose (a pentose sugar). Three phosphate groups are esterified at the fifth carbon atom of the ribose. ATP is incorporated into nucleic acids by polymerases in the processes of DNA replication and transcription. ATP contributes to cellular energy charge and participates in overall energy balance, maintaining cellular homeostasis. ATP can act as an extracellular signaling molecule via interactions with specific purinergic receptors to mediate a wide variety of processes as diverse as neurotransmission, inflammation, apoptosis, and bone remodelling. Extracellular ATP and its metabolite adenosine have also been shown to exert a variety of effects on nearly every cell type in human skin, and ATP seems to play a direct role in triggering skin inflammatory, regenerative, and fibrotic responses to mechanical injury, an indirect role in melanocyte proliferation and apoptosis, and a complex role in Langerhans cell-directed adaptive immunity. During exercise, intracellular homeostasis depends on the matching of adenosine triphosphate (ATP) supply and ATP demand. Metabolites play a useful role in communicating the extent of ATP demand to the metabolic supply pathways. Effects as different as proliferation or differentiation, chemotaxis, release of cytokines or lysosomal constituents, and generation of reactive oxygen or nitrogen species are elicited upon stimulation of blood cells with extracellular ATP. The increased concentration of adenosine triphosphate (ATP) in erythrocytes from patients with chronic renal failure (CRF) has been observed in many studies but the mechanism leading to these abnormalities still is controversial. (PMID: 15490415, 15129319, 14707763, 14696970, 11157473).
Adenosine triphosphate (ATP) is a nucleotide consisting of a purine base (adenine) attached to the first carbon atom of ribose (a pentose sugar). Three phosphate groups are esterified at the fifth carbon atom of the ribose. ATP is incorporated into nucleic acids by polymerases in the processes of DNA replication and transcription. ATP contributes to cellular energy charge and participates in overall energy balance, maintaining cellular homeostasis. ATP can act as an extracellular signaling molecule via interactions with specific purinergic receptors to mediate a wide variety of processes as diverse as neurotransmission, inflammation, apoptosis, and bone remodelling. Extracellular ATP and its metabolite adenosine have also been shown to exert a variety of effects on nearly every cell type in human skin, and ATP seems to play a direct role in triggering skin inflammatory, regenerative, and fibrotic responses to mechanical injury, an indirect role in melanocyte proliferation and apoptosis, and a complex role in Langerhans cell-directed adaptive immunity. During exercise, intracellular homeostasis depends on the matching of adenosine triphosphate (ATP) supply and ATP demand. Metabolites play a useful role in communicating the extent of ATP demand to the metabolic supply pathways. Effects as different as proliferation or differentiation, chemotaxis, release of cytokines or lysosomal constituents, and generation of reactive oxygen or nitrogen species are elicited upon stimulation of blood cells with extracellular ATP. The increased concentration of adenosine triphosphate (ATP) in erythrocytes from patients with chronic renal failure (CRF) has been observed in many studies but the mechanism leading to these abnormalities still is controversial. (PMID: 15490415, 15129319, 14707763, 14696970, 11157473).
Alanylleucine is a dipeptide composed of alanine and leucine. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
Allantoic acid is the end product of Allantoicase [EC:3.5.3.4], an enzyme involved in uric acid degradation (Purine metabolism). Although it is commonly accepted that allantoicase is lost in mammals, it has been identified in mice and humans. (PMID 11852104). A crystalline, transparent, colorless substance found in the allantoic liquid of the fetal calf. It was formerly called allantoic acid and amniotic acid.
Allantoin is a diureide of glyoxylic acid with the chemical formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a product of the oxidation of uric acid. It is also a product of purine metabolism in most mammals except for higher apes, and it is present in their urine. In humans, uric acid is excreted instead of allantoin. The presence of allantoin in the urine can be an indication of microbial overgrowth or it can be created via non-enzymatic means through high levels of reactive oxygen species. In this regard, allantoin is sometimes used as a marker of oxidative stress. Allantoin can be isolated from cow urine or as a botanical extract of the comfrey plant. It has long been used for its healing, soothing, and anti-irritating properties. Allantoin helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. Allantoin can be found in anti-acne products, sun care products, and clarifying lotions because of its ability to help heal minor wounds and promote healthy skin. Allantoin is frequently present in toothpaste, mouthwash, and other oral hygiene products as well as in shampoos, lipsticks, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products. It is also a metabolite of Bacillus (PMID: 18302748) and Streptomyces (PMID: 24292080).
Allantoin is a diureide of glyoxylic acid with the chemical formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a product of the oxidation of uric acid. It is also a product of purine metabolism in most mammals except for higher apes, and it is present in their urine. In humans, uric acid is excreted instead of allantoin. The presence of allantoin in the urine can be an indication of microbial overgrowth or it can be created via non-enzymatic means through high levels of reactive oxygen species. In this regard, allantoin is sometimes used as a marker of oxidative stress. Allantoin can be isolated from cow urine or as a botanical extract of the comfrey plant. It has long been used for its healing, soothing, and anti-irritating properties. Allantoin helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. Allantoin can be found in anti-acne products, sun care products, and clarifying lotions because of its ability to help heal minor wounds and promote healthy skin. Allantoin is frequently present in toothpaste, mouthwash, and other oral hygiene products as well as in shampoos, lipsticks, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products. It is also a metabolite of Bacillus (PMID: 18302748) and Streptomyces (PMID: 24292080).
Allantoin is a diureide of glyoxylic acid with the chemical formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a product of the oxidation of uric acid. It is also a product of purine metabolism in most mammals except for higher apes, and it is present in their urine. In humans, uric acid is excreted instead of allantoin. The presence of allantoin in the urine can be an indication of microbial overgrowth or it can be created via non-enzymatic means through high levels of reactive oxygen species. In this regard, allantoin is sometimes used as a marker of oxidative stress. Allantoin can be isolated from cow urine or as a botanical extract of the comfrey plant. It has long been used for its healing, soothing, and anti-irritating properties. Allantoin helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. Allantoin can be found in anti-acne products, sun care products, and clarifying lotions because of its ability to help heal minor wounds and promote healthy skin. Allantoin is frequently present in toothpaste, mouthwash, and other oral hygiene products as well as in shampoos, lipsticks, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products. It is also a metabolite of Bacillus (PMID: 18302748) and Streptomyces (PMID: 24292080).
Allantoin is a diureide of glyoxylic acid with the chemical formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a product of the oxidation of uric acid. It is also a product of purine metabolism in most mammals except for higher apes, and it is present in their urine. In humans, uric acid is excreted instead of allantoin. The presence of allantoin in the urine can be an indication of microbial overgrowth or it can be created via non-enzymatic means through high levels of reactive oxygen species. In this regard, allantoin is sometimes used as a marker of oxidative stress. Allantoin can be isolated from cow urine or as a botanical extract of the comfrey plant. It has long been used for its healing, soothing, and anti-irritating properties. Allantoin helps to heal wounds and skin irritations and stimulates the growth of healthy tissue. Allantoin can be found in anti-acne products, sun care products, and clarifying lotions because of its ability to help heal minor wounds and promote healthy skin. Allantoin is frequently present in toothpaste, mouthwash, and other oral hygiene products as well as in shampoos, lipsticks, various cosmetic lotions and creams, and other cosmetic and pharmaceutical products. It is also a metabolite of Bacillus (PMID: 18302748) and Streptomyces (PMID: 24292080).
(R)C(S)S-Alliin is found in garden onion. (R)C(S)S-Alliin is a constituent of garlic oil (Allium sativum), also from ramsons (Allium ursinum).
(R)C(S)S-Alliin is found in garden onion. (R)C(S)S-Alliin is a constituent of garlic oil (Allium sativum), also from ramsons (Allium ursinum).
Alloxan or mesoxalylurea is an organic compound based on a pyrimidine heterocyclic skeleton. This compound has a high affinity for water and therefore exists as the monohydrate. The compound was discovered by Justus von Liebig and Friedrich Wohler following the discovery of urea in 1828 and is one of the oldest named organic compounds that exist. The name is derived from allantoin, a product of uric acid excreted by the fetus into the allantois and oxaluric acid derived from oxalic acid and urea, found in urine. The original recipe for Alloxan was by oxidation of uric acid by nitric acid. Alloxan is a strong oxidizing agent and it forms a hemiacetal with its reduced reaction product dialuric acid (in which a carbonyl group is reduced to a hydroxyl group) which is called alloxantin. -- Wikipedia; Alloxane is a raw material for the production of the purple dye Murexide. Carl Wilhelm Scheele discovered the dye in 1776. Murexide is the product of the complex in-situ multistep reaction of alloxantin and gaseous ammonia. Murexide results from the condensation of the unisolated intermdiate uramil with alloxan, liberated during the course of the reaction. Scheele sourced uric acid from human calculi (such as kidney stones) and called the compound lithic acid. William Prout investigated the compound in 1818 and he used boa constrictor excrement with up to 90% ammonium acid urate. Liebig and Wohler in the nineteenth century coined the name murexide for the dye after the Trunculus Murex which is the source of the Tyrian purple of antiquity. Primo Levi in his world famous novel The Periodic Table in chapter Nitrogen considers pythons as a source for alloxane on behalf of a lipstick producer but he is turned down by the director of the Turin zoo because the zoo already has lucrative contracts with cosmetics companies (his attempts with chicken dung end in misery). -- Wikipedia.
Aminoadipic acid, also known as a-aminoadipate or Aad, belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Aminoadipic acid is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Aminoadipic acid exists in all eukaryotes, ranging from yeast to humans. Within humans, aminoadipic acid participates in a number of enzymatic reactions. In particular, aminoadipic acid can be biosynthesized from allysine; which is mediated by the enzyme Alpha-aminoadipic semialdehyde dehydrogenase. In addition, aminoadipic acid and oxoglutaric acid can be converted into oxoadipic acid and L-glutamic acid; which is catalyzed by the enzyme kynurenine/alpha-aminoadipate aminotransferase, mitochondrial. In humans, aminoadipic acid is involved in the metabolic disorder called 2-aminoadipic 2-oxoadipic aciduria. Outside of the human body, Aminoadipic acid is found, on average, in the highest concentration within a few different foods, such as wheats, milk (cow), and ryes and in a lower concentration in dills, garden onions, and white cabbages. Aminoadipic acid has also been detected, but not quantified in, several different foods, such as barley, cow milks, cow milks, cow milks, and cow milks. This could make aminoadipic acid a potential biomarker for the consumption of these foods. Aminoadipic acid is a potentially toxic compound. Aminoadipic acid, with regard to humans, has been found to be associated with several diseases such as alpha-aminoadipic and alpha-ketoadipic aciduria, colorectal cancer, metastatic melanoma, and eosinophilic esophagitis; aminoadipic acid has also been linked to the inborn metabolic disorder 2-ketoadipic acidemia.
Galactose 1-phosphate, also known as D-Galactose-1-phosphate or alpha-D-gal-1-P, belongs to the class of organic compounds known as monosaccharide phosphates. These are monosaccharides comprising a phosphate group linked to the carbohydrate unit. Galactose-1-phosphate is an intermediate in the interconversion of glucose and uridine diphosphate galactose. Galactose 1-phosphate exists in all living species, ranging from bacteria to plants to humans. Within humans, galactose 1-phosphate participates in a number of enzymatic reactions. In particular, uridine diphosphate glucose and galactose 1-phosphate can be biosynthesized from uridine diphosphategalactose and glucose 1-phosphate; which is mediated by the enzyme galactose-1-phosphate uridylyltransferase (GALT). In addition, galactose 1-phosphate can be biosynthesized from D-galactose through the action of the enzyme galactokinase. The improper metabolism of galactose-1-phosphate is a characteristic of a condition known as galactosemia (PMID: 7671964). Type I galactosemia is a genetic disorder that is caused by the impairment of galactose-1-phosphate uridylyltransferase (EC 2.7.7.12). Evidence suggests that misfolding of the galactose 1-phosphate uridylyltransferase enzyme is the underlying cause of type I galactosemia (PMID: 23583749). Outside of the human body, galactose 1-phosphate has been detected, but not quantified in, several different foods, such as gooseberries, anises, turmerics, caraway, and cumins.
Glucose 1-phosphate (also called cori ester) is a glucose molecule with a phosphate group on the 1'-carbon. It can exist in either the α- or β-anomeric form. Glucose 1-phosphate belongs to the class of organic compounds known as monosaccharide phosphates. These are monosaccharides comprising a phosphated group linked to the carbohydrate unit. Glucose 1-phosphate is the direct product of the reaction in which glycogen phosphorylase cleaves off a molecule of glucose from a greater glycogen structure. It cannot travel down many metabolic pathways and must be interconverted by the enzyme phosphoglucomutase in order to become glucose 6-phosphate. Free glucose 1-phosphate can also react with UTP to form UDP-glucose. It can then return to the greater glycogen structure via glycogen synthase.
2-Aminoisobutyric acid, also known as alpha-methylalanine or a-aminoisobutanoate, belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). 2-Aminoisobutyric acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. 2-Aminoisobutyric acid exists in all living organisms, ranging from bacteria to humans. Outside of the human body, 2-Aminoisobutyric acid has been detected, but not quantified in cow milk. Aminoisobutyric acid is a nonprotein amino acid (is an end product of pyrimidine metabolism) excreted in the urine of about 5% of healthy individuals (PMID 14806475), and high excretion is an autosomal recessive phenotype (PMID 13058271).
Adenosine monophosphate, also known as 5'-adenylic acid and abbreviated AMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. AMP consists of the phosphate group, the pentose sugar ribose, and the nucleobase adenine. AMP can be produced during ATP synthesis by the enzyme adenylate kinase. AMP has recently been approved as a 'Bitter Blocker' additive to foodstuffs. When AMP is added to bitter foods or foods with a bitter aftertaste it makes them seem 'sweeter'. This potentially makes lower calorie food products more palatable.
Adenosine monophosphate, also known as 5'-adenylic acid and abbreviated AMP, is a nucleotide that is found in RNA. It is an ester of phosphoric acid with the nucleoside adenosine. AMP consists of the phosphate group, the pentose sugar ribose, and the nucleobase adenine. AMP can be produced during ATP synthesis by the enzyme adenylate kinase. AMP has recently been approved as a 'Bitter Blocker' additive to foodstuffs. When AMP is added to bitter foods or foods with a bitter aftertaste it makes them seem 'sweeter'. This potentially makes lower calorie food products more palatable.
5-Androstenediol is a direct metabolite of the most abundant steroid produced by the human adrenal cortex, dehydroepiandrosterone (DHEA). 5-Androstenediol is less androgenic than 4-androstenediol, and stimulates the immune system. When administered to rats in vivo, 5-androstenediol has approximately 1/70 the androgenicity of DHEA, 1/185 the androgenicity of androstenedione, and 1/475 the androgenicity of testosterone (Wikipedia). Because it induces production of white blood cells and platelets, 5-androstenediol is being developed as a radiation countermeasure as Neumune (HE2100). An intermediate in testosterone biosynthesis, found in the testis or the adrenal glands. 5-Androstenediol, derived from dehydroepiandrosterone by the reduction of the 17-keto group (17-hydroxysteroid dehydrogenases), is converted to testosterone by the oxidation of the 3-beta hydroxyl group to a 3-keto group (3-fydroxysteroid dehydrogenase).
5-Androstenediol is a direct metabolite of the most abundant steroid produced by the human adrenal cortex, dehydroepiandrosterone (DHEA). 5-Androstenediol is less androgenic than 4-androstenediol, and stimulates the immune system. When administered to rats in vivo, 5-androstenediol has approximately 1/70 the androgenicity of DHEA, 1/185 the androgenicity of androstenedione, and 1/475 the androgenicity of testosterone (Wikipedia). Because it induces production of white blood cells and platelets, 5-androstenediol is being developed as a radiation countermeasure as Neumune (HE2100). An intermediate in testosterone biosynthesis, found in the testis or the adrenal glands. 5-Androstenediol, derived from dehydroepiandrosterone by the reduction of the 17-keto group (17-hydroxysteroid dehydrogenases), is converted to testosterone by the oxidation of the 3-beta hydroxyl group to a 3-keto group (3-fydroxysteroid dehydrogenase).
Aniline is an organic chemical compound, specifically a primary aromatic amine. It consists of a benzene ring attached to an amino group. Aniline is oily and, although colorless, it can be slowly oxidized and resinified in air to form impurities which can give it a red-brown tint. Its boiling point is 184 degree centigrade and its melting point is -6 degree centegrade. It is a liquid at room temperature. Like most volatile amines, it possesses a somewhat unpleasant odour of rotten fish, and also has a burning aromatic taste; it is a highly acrid poison. It ignites readily, burning with a large smoky flame. Aniline reacts with strong acids to form salts containing the anilinium (or phenylammonium) ion (C6H5-NH3+), and reacts with acyl halides (such as acetyl chloride (ethanoyl chloride), CH3COCl) to form amides. The amides formed from aniline are sometimes called anilides, for example CH3-CO-NH-C6H5 is acetanilide, for which the modern name is N-phenyl ethanamide. Like phenols, aniline derivatives are highly reactive in electrophilic substitution reactions. For example, sulfonation of aniline produces sulfanilic acid, which can be converted to sulfanilamide. Sulfanilamide is one of the sulfa drugs which were widely used as antibacterial in the early 20th century. Aniline was first isolated from the destructive distillation of indigo in 1826 by Otto Unverdorben. In 1834, Friedrich Runge isolated from coal tar a substance which produced a beautiful blue color on treatment with chloride of lime; this he named kyanol or cyanol. In 1841, C. J. Fritzsche showed that by treating indigo with caustic potash it yielded an oil, which he named aniline, from the specific name of one of the indigo-yielding plants, Indigofera anil, anil being derived from the Sanskrit, dark-blue.
2-Aminobenzoic acid, also known as anthranilic acid or O-aminobenzoate, belongs to the class of organic compounds known as aminobenzoic acids. These are benzoic acids containing an amine group attached to the benzene moiety. Within humans, 2-aminobenzoic acid participates in a number of enzymatic reactions. In particular, 2-aminobenzoic acid and formic acid can be biosynthesized from formylanthranilic acid through its interaction with the enzyme kynurenine formamidase. In addition, 2-aminobenzoic acid and L-alanine can be biosynthesized from L-kynurenine through its interaction with the enzyme kynureninase. It is a substrate of enzyme 2-Aminobenzoic acid hydroxylase in benzoate degradation via hydroxylation pathway (KEGG). In humans, 2-aminobenzoic acid is involved in tryptophan metabolism. Outside of the human body, 2-Aminobenzoic acid has been detected, but not quantified in several different foods, such as mamey sapotes, prairie turnips, rowals, natal plums, and hyacinth beans. This could make 2-aminobenzoic acid a potential biomarker for the consumption of these foods. 2-Aminobenzoic acid is a is a tryptophan-derived uremic toxin with multidirectional properties that can affect the hemostatic system. Uremic syndrome may affect any part of the body and can cause nausea, vomiting, loss of appetite, and weight loss. Chronic exposure of uremic toxins can lead to a number of conditions including renal damage, chronic kidney disease and cardiovascular disease. It can also cause changes in mental status, such as confusion, reduced awareness, agitation, psychosis, seizures, and coma.
D-Arabitol is a polyol. Polyols are sugar alcohols linked to the pentose phosphate pathway (PPP). They are classified on the basis of the number of carbon atoms. Polyols occur in body fluids. A patient with leukoencephalopathy and peripheral neuropathy has been identified as suffering from ribose-5-phosphate isomerase (RPI) deficiency, a defect in the PPP. In this disorder, highly elevated concentrations of the C5 polyols such as D-arabitol are found in body fluids. In addition, transaldolase deficiency, another defect in the PPP, has been diagnosed in a patient with mainly liver problems among others. This patient had increased concentrations of polyols, mainly D-arabitol. So far, the pathophysiological role of polyols is relatively unknown. It is thought that D-arabitol is a metabolic end-product in humans. The strong brain-CSF-plasma gradient of polyols in the patient with RPI deficiency suggested a primary metabolic disorder. The mechanisms of brain and neuronal damage in RPI deficiency remain to be elucidated. A neurotoxic effect due to the accumulation of the polyols may play a role. D-Arabitol is a product of the enzyme D-arabinitol 4-dehydrogenase (EC 1.1.1.11) in the pentose and glucuronate interconversion pathway (PMID: 16435225, J Inherit Metab Dis. 2005;28(6):1181-3). D-Arabitol has also been found to be a fungal metabolite, urinary D-Arabinitol is a marker for invasive candidiasis or infection by Candida fungal species (PMID: 15183861; PMID: 10647119). It can also a metabolite in Debaryomyces, Pichia and Zygosaccharomyces (PMID: 25809659).
D-Arabitol is a polyol. Polyols are sugar alcohols linked to the pentose phosphate pathway (PPP). They are classified on the basis of the number of carbon atoms. Polyols occur in body fluids. A patient with leukoencephalopathy and peripheral neuropathy has been identified as suffering from ribose-5-phosphate isomerase (RPI) deficiency, a defect in the PPP. In this disorder, highly elevated concentrations of the C5 polyols such as D-arabitol are found in body fluids. In addition, transaldolase deficiency, another defect in the PPP, has been diagnosed in a patient with mainly liver problems among others. This patient had increased concentrations of polyols, mainly D-arabitol. So far, the pathophysiological role of polyols is relatively unknown. It is thought that D-arabitol is a metabolic end-product in humans. The strong brain-CSF-plasma gradient of polyols in the patient with RPI deficiency suggested a primary metabolic disorder. The mechanisms of brain and neuronal damage in RPI deficiency remain to be elucidated. A neurotoxic effect due to the accumulation of the polyols may play a role. D-Arabitol is a product of the enzyme D-arabinitol 4-dehydrogenase (EC 1.1.1.11) in the pentose and glucuronate interconversion pathway (PMID: 16435225, J Inherit Metab Dis. 2005;28(6):1181-3). D-Arabitol has also been found to be a fungal metabolite, urinary D-Arabinitol is a marker for invasive candidiasis or infection by Candida fungal species (PMID: 15183861; PMID: 10647119). It can also a metabolite in Debaryomyces, Pichia and Zygosaccharomyces (PMID: 25809659).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arabinonic acid (CAS: 13752-83-5) is a substrate of L-arabinonate dehydratase [EC 4.2.1.25] in the pathway ascorbate and aldarate metabolism (KEGG).
Arbutin is found in apple. Glucoside in pear leaves (Pyrus communis
Ascorbic acid is found naturally in citrus fruits and many vegetables and is an essential nutrient in human diets. It is necessary to maintain connective tissue and bone. The biologically active form of ascorbic acid is vitamin C. Vitamin C is a water soluble vitamin. Primates (including humans) and a few other species in all divisions of the animal kingdom, notably the guinea pig, have lost the ability to synthesize ascorbic acid and must obtain it in their food. Vitamin C functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant (PubChem). Ascorbic acid is an electron donor for enzymes involved in collagen hydroxylation, biosynthesis of carnitine and norepinephrine, tyrosine metabolism, and amidation of peptide hormones. Ascrobic acid (vitamin C) deficiency causes scurvy. The amount of vitamin C necessary to prevent scurvy may not be adequate to maintain optimal health. The ability of vitamin C to donate electrons also makes it a potent water-soluble antioxidant that readily scavenges free radicals such as molecular oxygen, superoxide, hydroxyl radical, and hypochlorous acid. In this setting, several mechanisms could account for a link between vitamin C and heart disease. One is the relation between LDL oxidation and vitamins C and E. Vitamin C in vitro can recycle vitamin E, which can donate electrons to prevent LDL oxidation in vitro. As the lipid-phase vitamin E is oxidized, it can be regenerated by aqueous vitamin C. Other possibilities are that vitamin C could decrease cholesterol by mechanisms not well characterized, or could improve vasodilatation and vascular reactivity, perhaps by decreasing the interactions of nitric oxide with oxidants (PMID: 10799361). Moreover, ascorbic acid is found to be associated with hyperoxalemia, which is an inborn error of metabolism. Ascorbic acid is also a microbial metabolite produced by Ketogulonicigenium (PMID: 15785002).
Aspartyl-Aspartate is a dipeptied compoosed of two aspartate residues. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
Aspartyl-Glutamate is a dipeptide composed of aspartate and glutamate. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
D-Asparagine, also known as DSG, belongs to the class of organic compounds known as asparagine and derivatives. D-Asparagome is a non-essential amino acid that is involved in the metabolic control of cell functions in nerve and brain tissue. Asparagine and derivatives are compounds containing asparagine or a derivative thereof resulting from reaction of asparagine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. It is codified by the codons AAU and AAC. It is biosynthesized from Aspartic acid and Ammonia by asparagine synthetase.
Asymmetric dimethylarginine (ADMA) is a naturally occurring chemical found in blood plasma. It is a metabolic by-product of continual protein modification processes in the cytoplasm of all human cells. It is closely related to L-arginine, a conditionally-essential amino acid. ADMA interferes with L-arginine in the production of nitric oxide, a key chemical to endothelial and hence cardiovascular health. Asymmetric dimethylarginine is created in protein methylation, a common mechanism of post-translational protein modification. This reaction is catalyzed by an enzyme set called S-adenosylmethionine protein N-methyltransferases (protein methylases I and II). The methyl groups transferred to create ADMA are derived from the methyl group donor S-adenosylmethionine, an intermediate in the metabolism of homocysteine. (Homocysteine is an important blood chemical, because it is also a marker of cardiovascular disease). After synthesis, ADMA migrates into the extracellular space and thence into blood plasma. Asymmetric dimethylarginine is measured using high performance liquid chromatography. ADMA has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
Atenolol is a so-called beta1-selective (or 'cardioselective') drug. That means that it exerts greater blocking activity on myocardial beta1-receptors than on beta2 ones in the lung. The beta2 receptors are responsible to keep the bronchial system open. If these receptors are blocked, bronchospasm with serious lack of oxygen in the body can result. However, due to its cardioselective properties, the risk of bronchospastic reactions if using atenolol is reduced compared to nonselective drugs as propranolol. Nonetheless, this reaction may also be encountered with atenolol, particularly with high doses. Extreme caution should be exerted if atenolol is given to asthma patients, who are particularly at risk; the dose should be as low as possible. If an asthma attack occurs, the inhalation of a beta2-mimetic antiasthmatic, such as hexoprenalin or salbutamol, will usually suppress the symptoms. Atenolol (trade name Tenormin) can be used to treat cardiovascular diseases such as hypertension, coronary heart disease, arrhythmias, and treatment of myocardial infarction after the acute event. Patients with compensated congestive heart failure may be treated with atenolol as a co medication (usually together with an ACE inhibitor, a diuretic and a digitalis-glycoside, if indicated). In patients with congestive heart failure, it reduces the need for and the consumption of oxygen of the heart muscle. It is very important to start with low doses, as atenolol reduces also the muscular power of the heart, which is an undesired effect in congestive heart failure.
Azelaic acid (AZA) is a naturally occurring saturated nine-carbon dicarboxylic acid (COOH (CH2)7-COOH). It possesses a variety of biological actions both in vitro and in vivo. Interest in the biological activity of AZA arose originally out of studies of skin surface lipids and the pathogenesis of hypochromia in pityriasis versicolor infection. Later, it was shown that Pityrosporum can oxidize unsaturated fatty acids to C8-C12 dicarboxylic acids that are cornpetitive inhibitors of tyrosinase in vitro. Azelaic acid was chosen for further investigation and development of a new topical drug for treating hyperpigmentary disorders for the following reasons: it possesses a middle-range of antityrosinase activity, is inexpensive, and more soluble to be incorporated into a base cream than other dicarboxylic acids. Azelaic acid is another option for the topical treatment of mild to moderate inflammatory acne vulgaris. It offers effectiveness similar to that of other agents without the systemic side effects of oral antibiotics or the allergic sensitization of topical benzoyl peroxide and with less irritation than tretinoin. Azelaic acid is less expensive than certain other prescription acne preparations, but it is much more expensive than nonprescription benzoyl peroxide preparations. Whether it is safe and effective when used in combination with other agents is not known. (PMID: 7737781, 8961845).
beta-Citryl-L-glutamic acid (beta-CG) is a derivative of glutamic acid. beta-CG which is known to occur in the brain, have been isolated from human urine.
Nicotinamide adenine dinucleotide phosphate (NADP) is a coenzyme composed of ribosylnicotinamide 5'-phosphate (NMN) coupled with a pyrophosphate linkage to 5'-phosphate adenosine 2',5'-bisphosphate. NADP serves as an electron carrier in a number of reactions, being alternately oxidized (NADP+) and reduced (NADPH). NADP is formed through the addition of a phosphate group to the 2' position of the adenosyl nucleotide through an ester linkage (Dorland, 27th ed). This extra phosphate is added by the enzyme NAD+ kinase and removed via NADP+ phosphatase. NADP is also known as TPN (triphosphopyridine nucleotide) and it is an important cofactor used in anabolic reactions in all forms of cellular life. Examples include the Calvin cycle, cholesterol synthesis, fatty acid elongation, and nucleic acid synthesis (Wikipedia).
Betonicine (4-hydroxy-L-prolinebetaine) and its cis isomer, turicine, are naturally occurring substituted pyrrolidines. It is not naturally produced by humans and can only be obtained through consumption of certain plant products. Betonicine was used as an analgesic 1000 years ago and is still available commercially from herbalists today. Betonicine has been isolated from Achillea millefolium L. (common yarrow) and probably from A. atrata L. (black yarrow); it is an alkaloid. Betonicine has been identified as a metabolically inert cell protectant that protects plants against extremes in osmolarity and growth temperatures. Betonicine is found in the fruit juices of yellow orange, blood orange, lemon, mandarin and bitter orange (PMID: 21838291)
Betonicine (4-hydroxy-L-prolinebetaine) and its cis isomer, turicine, are naturally occurring substituted pyrrolidines. It is not naturally produced by humans and can only be obtained through consumption of certain plant products. Betonicine was used as an analgesic 1000 years ago and is still available commercially from herbalists today. Betonicine has been isolated from Achillea millefolium L. (common yarrow) and probably from A. atrata L. (black yarrow); it is an alkaloid. Betonicine has been identified as a metabolically inert cell protectant that protects plants against extremes in osmolarity and growth temperatures. Betonicine is found in the fruit juices of yellow orange, blood orange, lemon, mandarin and bitter orange (PMID: 21838291)
Biliverdin is a green pigment formed as a byproduct of hemoglobin breakdown. It consists of four linearly connected pyrrole rings (a tetrapyrrole). Biliverdin is formed when the heme group in hemoglobin is cleaved at its alpha-methene bridge. The resulting biliverdin is then reduced to bilirubin, a yellow pigment, by the enzyme biliverdin reductase. The changing color of a bruise from deep purple to yellow over time is a graphical indicator of this reaction. Biliverdin occurs in the bile of amphibia and of birds, but not in normal human bile or serum.
Biliverdin is a green pigment formed as a byproduct of hemoglobin breakdown. It consists of four linearly connected pyrrole rings (a tetrapyrrole). Biliverdin is formed when the heme group in hemoglobin is cleaved at its alpha-methene bridge. The resulting biliverdin is then reduced to bilirubin, a yellow pigment, by the enzyme biliverdin reductase. The changing color of a bruise from deep purple to yellow over time is a graphical indicator of this reaction. Biliverdin occurs in the bile of amphibia and of birds, but not in normal human bile or serum.
The phytoestrogen biochanin A is an isoflavone derivative isolated from red clover Trifolium pratense with anticarcinogenic properties. Treating MCF-7 human breast carcinoma cells with biochanin A alone caused the accumulation of CYP1A1 mRNA and an increase in CYP1A1-specific 7-ethoxyresorufin O-deethylase (EROD) activity in a dose dependent manner. Biochanin A may be a natural ligand to bind on aryl hydrocarbon receptor acting as an antagonist/agonist of the pathway. (PMID: 16903077). Biochanin A suppress nuclear factor-kappaB-driven interleukin-6 (IL6) expression. In addition to its physiologic immune function as an acute stress cytokine, sustained elevated expression levels of IL6 promote chronic inflammatory disorders, aging frailty, and tumorigenesis. (PMID: 16651441). Biochanin A induces a decrease in invasive activity of U87MG cells in a dose-related manner. (PMID: 16598420). Biochanin A activates peroxisome proliferator-activated receptors (PPAR) PPARalpha, PPARgamma, and adipocyte differentiation in vitro of 3T3-L1 preadipocytes, suggesting potential value of isoflavones, especially biochanin A and their parent botanicals, as antidiabetic agents and for use in regulating lipid metabolism. (PMID: 16549448).
4-Trimethylammoniobutanoic acid, also known as gamma-butyrobetaine (GBB) or 3-dehydroxycarnitine, is a highly water-soluble derivative of gamma-aminobutyric acid (GABA). It is also a precursor of L-carnitine. It is a substrate of gamma butyrobetaine hydroxylase/dioxygenase (also known as BBOX) which catalyzes the formation of L-carnitine from gamma-butyrobetaine, the last step in the L-carnitine biosynthesis pathway. Carnitine is essential for the transport of activated fatty acids across the mitochondrial membrane during mitochondrial beta-oxidation. Numerous disorders have been described that lead to disturbances in energy production and in intermediary metabolism which are characterized by the production and excretion of unusual acylcarnitines. A mutation in the gene coding for carnitine-acylcarnitine translocase, or the OCTN2 transporter aetiologically, causes a carnitine deficiency that results in poor intestinal absorption of dietary L-carnitine, impaired reabsorption by the kidney, and increased urinary loss. Determination of the qualitative pattern of acylcarnitines can be of diagnostic and therapeutic importance. The betaine structure of carnitine requires special analytical procedures for recording. The ionic nature of L-carnitine causes a high water solubility which decreases with increasing chain length of the ester group in the acylcarnitines. Therefore, the distribution of L-carnitine and acylcarnitines in various organs is defined by their function and their physicochemical properties as well. High-performance liquid chromatography (HPLC) permits screening for free and total carnitine, as well as complete quantitative acylcarnitine determination, including the long-chain acylcarnitine profile (PMID: 17508264, Monatshefte fuer Chemie (2005), 136(8), 1279-1291., Int J Mass Spectrom. 1999;188:39-52.).
N-Butyrylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism, such as ethylmalonic encephalopathy. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13), which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine amino acids composed of glycine substituted at the nitrogen rather than the usual carbon position, resulting in the loss of hydrogen bonding donors. Polymers of these compounds are called Peptoids.
Tryptophan 2-C-mannoside, also known as 2-alpha-D-mannopyranosyl-L-tryptophan or C-mannosyltryptophan, belongs to the class of organic compounds known as indolyl carboxylic acids and derivatives. Indolyl carboxylic acids and derivatives are compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an indole ring. It is an L-tryptophan derivative and a C-glycosyl compound in which the hydrogen at position 2 on the indole portion has been replaced by an alpha-mannosyl residue. Tryptophan 2-C-mannoside is a very strong basic compound (based on its pKa). Tryptophan 2-C-mannoside has been identified in blood and urine and is a marker of kidney function (PMID: 29234020).
Tetradecanoylcarnitine, also known as myristoylcarnitine, is a member of the class of compounds known as acylcarnitines. Acylcarnitines are organic compounds containing a fatty acid with the carboxylic acid attached to carnitine through an ester bond. Acylcarnitines are useful in the diagnosis of genetic disorders such as fatty acid oxidation disorders and differentiation between biochemical phenotypes of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency disorders (PMID: 12385891). Tetradecanoylcarnitine is involved in the beta-oxidation of long-chain fatty acids (PMID: 16425363). Tetradecanoylcarnitine is found to be associated with glutaric aciduria II, which is an inborn error of metabolism.
Tetradecanoylcarnitine, also known as myristoylcarnitine, is a member of the class of compounds known as acylcarnitines. Acylcarnitines are organic compounds containing a fatty acid with the carboxylic acid attached to carnitine through an ester bond. Acylcarnitines are useful in the diagnosis of genetic disorders such as fatty acid oxidation disorders and differentiation between biochemical phenotypes of medium-chain acyl-CoA dehydrogenase (MCAD) deficiency disorders (PMID: 12385891). Tetradecanoylcarnitine is involved in the beta-oxidation of long-chain fatty acids (PMID: 16425363). Tetradecanoylcarnitine is found to be associated with glutaric aciduria II, which is an inborn error of metabolism.
Stearoylcarnitine, also known as acylcarnitine C18:0, is a fatty ester lipid molecule. It is found in significantly greater amounts of patients with carnitine palmitoyltransferase (CPT) II deficiency when compared to controls (PMID:15653102). Stearoylcarnitine is also found to be associated with celiac disease, another inborn error of metabolism. The carnitine palmitoyltransferase (CPT; EC 2.3.1.21) enzyme system, in conjunction with acyl-CoA synthetase and carnitine/acylcarnitine translocase, provides the mechanism whereby long-chain fatty acids are transferred from the cytosol to the mitochondrial matrix to undergo beta-oxidation (OMIM: 600650). Stearoylcarnitine is considered to be practically insoluble in water and acidic.
Oleic acid (or 9Z)-Octadecenoic acid) is an unsaturated C-18 or an omega-9 fatty acid that is the most widely distributed and abundant fatty acid in nature. It occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. The name derives from the Latin word oleum, which means oil. Oleic acid is the most abundant fatty acid in human adipose tissue, and the second most abundant in human tissues overall, following palmitic acid. Oleic acid is a component of the normal human diet, being a part of animal fats and vegetable oils. Triglycerides of oleic acid represent the majority of olive oil (about 70%). Oleic acid triglycerides also make up 59‚Äì75% of pecan oil, 61% of canola oil, 36‚Äì67% of peanut oil, 60% of macadamia oil, 20‚Äì80% of sunflower oil, 15‚Äì20% of grape seed oil, sea buckthorn oil, 40% of sesame oil, and 14% of poppyseed oil. High oleic variants of plant sources such as sunflower (~80%) and canola oil (70%) also have been developed. consumption has been associated with decreased low-density lipoprotein (LDL) cholesterol, and possibly with increased high-density lipoprotein (HDL) cholesterol, however, the ability of oleic acid to raise HDL is still debated. Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil that is considered a health benefit. Oleic acid is used in manufacturing of surfactants, soaps, plasticizers. It is also used as an emulsifying agent in foods and pharmaceuticals. Oleic acid is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent.
Oleic acid (or 9Z)-Octadecenoic acid) is an unsaturated C-18 or an omega-9 fatty acid that is the most widely distributed and abundant fatty acid in nature. It occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. The name derives from the Latin word oleum, which means oil. Oleic acid is the most abundant fatty acid in human adipose tissue, and the second most abundant in human tissues overall, following palmitic acid. Oleic acid is a component of the normal human diet, being a part of animal fats and vegetable oils. Triglycerides of oleic acid represent the majority of olive oil (about 70%). Oleic acid triglycerides also make up 59‚Äì75% of pecan oil, 61% of canola oil, 36‚Äì67% of peanut oil, 60% of macadamia oil, 20‚Äì80% of sunflower oil, 15‚Äì20% of grape seed oil, sea buckthorn oil, 40% of sesame oil, and 14% of poppyseed oil. High oleic variants of plant sources such as sunflower (~80%) and canola oil (70%) also have been developed. consumption has been associated with decreased low-density lipoprotein (LDL) cholesterol, and possibly with increased high-density lipoprotein (HDL) cholesterol, however, the ability of oleic acid to raise HDL is still debated. Oleic acid may be responsible for the hypotensive (blood pressure reducing) effects of olive oil that is considered a health benefit. Oleic acid is used in manufacturing of surfactants, soaps, plasticizers. It is also used as an emulsifying agent in foods and pharmaceuticals. Oleic acid is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent.
Linoleic acid is a doubly unsaturated fatty acid, also known as an omega-6 fatty acid, occurring widely in plant glycosides. In this particular polyunsaturated fatty acid (PUFA), the first double bond is located between the sixth and seventh carbon atom from the methyl end of the fatty acid (n-6). Linoleic acid is an essential fatty acid in human nutrition because it cannot be synthesized by humans. It is used in the biosynthesis of prostaglandins (via arachidonic acid) and cell membranes (From Stedman, 26th ed). Linoleic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.
Linoleic acid is a doubly unsaturated fatty acid, also known as an omega-6 fatty acid, occurring widely in plant glycosides. In this particular polyunsaturated fatty acid (PUFA), the first double bond is located between the sixth and seventh carbon atom from the methyl end of the fatty acid (n-6). Linoleic acid is an essential fatty acid in human nutrition because it cannot be synthesized by humans. It is used in the biosynthesis of prostaglandins (via arachidonic acid) and cell membranes (From Stedman, 26th ed). Linoleic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.
gamma-Linolenic acid, also known as 18:3n6 or GLA, belongs to the class of organic compounds known as linoleic acids and derivatives. These are derivatives of linoleic acid. Linoleic acid is a polyunsaturated omega-6 18-carbon long fatty acid, with two CC double bonds at the 9- and 12-positions. gamma-Linolenic acid is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. gamma-Linolenic acid is an omega-6 fatty acid produced in the body as the delta 6-desaturase metabolite of linoleic acid. It is converted into dihomo-gamma-linolenic acid, a biosynthetic precursor of monoenoic prostaglandins such as PGE1 (PubChem).
Docosahexaenoic acid (DHA) is an omega-3 essential fatty acid. Chemically, DHA is a carboxylic acid with a 22-carbon chain and six cis- double bonds with the first double bond located at the third carbon from the omega end. DHA is most often found in fish oil. It is a major fatty acid in sperm and brain phospholipids, especially in the retina. Dietary DHA can reduce the level of blood triglycerides in humans, which may reduce the risk of heart disease (Wikipedia). Docosahexaenoic acid is found to be associated with isovaleric acidemia, which is an inborn error of metabolism.
Malonylcarnitine is a metabolite that accumulates with specific disruption of fatty-acid oxidation caused by the impaired entry of long-chain acylcarnitine esters into the mitochondria and failure of the mitochondrial respiratory chain at complex 11 and malonyl-CoA decarboxylase (EC 4.1.1.9) deficiency (OMIM: 248360). Malonylcarnitine has also been found to accumulate in some newborns with medium-chain acyl-CoA dehydrogenase (EC 1.3.99.3) deficiency (OMIM: 201450). (PMID:11558490, 15303003, 12651823).
Butyrylcarnitine, also known as (3R)-3-(butyryloxy)-4-(trimethylammonio)butanoate or L-carnitine butyryl ester, is classified as a member of the acylcarnitines. Acylcarnitines are organic compounds containing a fatty acid with the carboxylic acid attached to carnitine through an ester bond. Butyrylcarnitine is considered to be practically insoluble (in water) and acidic. Butyrylcarnitine is elevated in patients with short-chain acyl-CoA dehydrogenase (SCAD) deficiency, in infants with acute acidosis and generalized muscle weakness, and in middle-aged patients with chronic myopathy localized in muscle (OMIM: 201470).
Hexanoylcarnitine (CAS: 6418-78-6), also known as caproylcarnitine, is an acylcarnitine. Acylcarnitines are the product of the conjugation of carnitine with acyl-coenzyme A, that allows the transport of fatty acids across mitochondrial membranes. Long or medium chain fatty acids are then oxidized in the mitochondria for energy production. The ionic nature of L-carnitine causes high water solubility which decreases with increasing chain lengths of the ester group in the acylcarnitines. Therefore, the distribution of L-carnitine and acylcarnitines in various organs is defined not only by their function but also by their physicochemical properties. Hexanoylcarnitine is a medium-chain acylcarnitine present in the urine of patients with medium-chain acyl-CoA dehydrogenase deficiency (PMID: 1635814). Hexanoylcarnitine is also found to be associated with celiac disease and glutaric aciduria II which are both inborn errors of metabolism. Numerous disorders have been described that lead to disturbances in energy production and in intermediary metabolism, which are characterized by the production and excretion of unusual acylcarnitines. A mutation in the gene coding for carnitine-acylcarnitine translocase or the OCTN2 transporter aetiologically causes a carnitine deficiency that results in poor intestinal absorption of dietary L-carnitine, its impaired reabsorption by the kidney and, consequently, in increased urinary loss of L-carnitine. Determination of the qualitative pattern of acylcarnitines can be of diagnostic and therapeutic importance. The betaine structure of carnitine requires special analytical procedures for recording. High-performance liquid chromatography (HPLC) permits screening for free and total carnitine, as well as complete quantitative acylcarnitine determination, including the long-chain acylcarnitine profile (PMID: 17508264, Monatshefte fuer Chemie (2005), 136(8), 1279-1291., Int J Mass Spectrom. 1999;188:39-52.).
L-Octanoylcarnitine is the physiologically active form of octanoylcarnitine (PMID: 11274033). Octanoylcarnitine is detected in medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. MCAD is characterized by an intolerance to prolonged fasting, recurrent episodes of hypoglycemic coma with medium-chain dicarboxylic aciduria, impaired ketogenesis, and low plasma and tissue carnitine levels (OMIM: 201450). L-Octanoylcarnitine is also found to be associated with celiac disease and glutaric aciduria II, which are inborn errors of metabolism.
Caffeic acid 3-O-sulfate (CAS: 1208232-16-9) is a polyphenol metabolite detected in biological fluids (PMID: 20428313). Caffeic acid sulfate was found to be elevated in rat urine after whole rye consumption which makes this compound a potential urinary biomarker of whole grain intake (PMID: 26862900).
Cyclic AMP (cAMP) or cyclic adenosine monophosphate is an adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. cAMP is found in all organisms ranging from bacteria to plants to animals. In humans and other mammals it is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon and ACTH. cAMP is synthesized from ATP by adenylate cyclase. Adenylate cyclase is located at the inner side of cell membranes. Adenylate cyclase is activated by the hormones glucagon and adrenaline and by G protein. Liver adenylate cyclase responds more strongly to glucagon, and muscle adenylate cyclase responds more strongly to adrenaline. cAMP decomposition into AMP is catalyzed by the enzyme phosphodiesterase. cAMP is primarily used for intracellular signal transduction, such as transferring into cells the effects of hormones like glucagon and adrenaline, which cannot pass through the plasma membrane. cAMP is also involved in the activation of protein kinases. In addition, cAMP binds to and regulates the function of ion channels such as the HCN channels. Hyperpolarization-activated cyclic nucleotide‚Äìgated (HCN) channels are integral membrane proteins that serve as nonselective voltage-gated cation channels in the plasma membranes of heart and brain cells. HCN channels are sometimes referred to as pacemaker channels because they help to generate rhythmic activity within groups of heart and brain cells.
Cyclic AMP (cAMP) or cyclic adenosine monophosphate is an adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. cAMP is found in all organisms ranging from bacteria to plants to animals. In humans and other mammals it is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon and ACTH. cAMP is synthesized from ATP by adenylate cyclase. Adenylate cyclase is located at the inner side of cell membranes. Adenylate cyclase is activated by the hormones glucagon and adrenaline and by G protein. Liver adenylate cyclase responds more strongly to glucagon, and muscle adenylate cyclase responds more strongly to adrenaline. cAMP decomposition into AMP is catalyzed by the enzyme phosphodiesterase. cAMP is primarily used for intracellular signal transduction, such as transferring into cells the effects of hormones like glucagon and adrenaline, which cannot pass through the plasma membrane. cAMP is also involved in the activation of protein kinases. In addition, cAMP binds to and regulates the function of ion channels such as the HCN channels. Hyperpolarization-activated cyclic nucleotide‚Äìgated (HCN) channels are integral membrane proteins that serve as nonselective voltage-gated cation channels in the plasma membranes of heart and brain cells. HCN channels are sometimes referred to as pacemaker channels because they help to generate rhythmic activity within groups of heart and brain cells.
Carvedilol is only found in individuals that have used or taken this drug. It is a non-selective beta blocker indicated in the treatment of mild to moderate congestive heart failure (CHF).Carvedilol is a racemic mixture in which nonselective beta-adrenoreceptor blocking activity is present in the S(-) enantiomer and alpha-adrenergic blocking activity is present in both R(+) and S(-) enantiomers at equal potency. Carvedilol's beta-adrenergic receptor blocking ability decreases the heart rate, myocardial contractility, and myocardial oxygen demand. Carvedilol also decreases systemic vascular resistance via its alpha adrenergic receptor blocking properties. Carvedilol and its metabolite BM-910228 (a less potent beta blocker, but more potent antioxidant) have been shown to restore the inotropic responsiveness to Ca<sup>2+</sup> in OH<sup>-</sup> free radical-treated myocardium. Carvedilol and its metabolites also prevent OH<sup>-</sup> radical-induced decrease in sarcoplasmic reticulum Ca<sup>2+</sup>-ATPase activity. Therefore, carvedilol and its metabolites may be beneficial in chronic heart failure by preventing free radical damage.
Catechin, also known as cyanidanol or catechuic acid, belongs to the class of organic compounds known as catechins. Catechins are compounds containing a catechin moiety, which is a 3,4-dihydro-2-chromene-3,5.7-tiol. Catechin also belongs to the group of compounds known as flavan-3-ols (or simply flavanols), part of the chemical family of flavonoids. Catechin is one of the 4 catechin known diastereoisomers. Two of the isomers are in trans configuration and are called catechin and the other two are in cis configuration and are called epicatechin. The most common catechin isomer is the (+)-catechin. The other stereoisomer is (-)-catechin or ent-catechin. The most common epicatechin isomer is (-)-epicatechin. Catechin is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Catechin is a bitter tasting compound and is associated with the bitterness in tea. Catechin is a plant secondary metabolite. Secondary metabolites are metabolically or physiologically non-essential metabolites that may serve a role as defense or signalling molecules. In some cases they are simply molecules that arise from the incomplete metabolism of other secondary metabolites. Catechin is an antioxidant flavonoid, occurring especially in woody plants as both Catechin and (-)-Catechin (cis) forms. Outside of the human body, Catechin is found, on average, in the highest concentration in foods, such as blackcurrants (Ribes nigrum), evergreen blackberries (Rubus laciniatus), and blackberries (Rubus) and in a lower concentration in dills (Anethum graveolens), hot chocolates, and medlars (Mespilus germanica). Catechin has also been detected, but not quantified in, several different foods, such as rice (Oryza sativa), apple ciders, peanuts (Arachis hypogaea), fruit juices, and red teas. This could make catechin a potential biomarker for the consumption of these foods. Based on a literature review a significant number of articles have been published on Catechin.
Pyrocatechol, often known as catechol or benzene-1,2-diol, is a benzenediol, with formula C6H4(OH)2. It was first prepared in 1839 by H. Reinsch by distilling catechin (the juice of Mimosa catechu). This colourless compound occurs naturally, but about 20000 tons are manufactured each year, mainly as precursors to pesticides, flavors, and fragrances. Its sulfonic acid is often present in the urine of many mammals. Small amounts of catechol occur naturally in fruits and vegetables, along with the enzyme polyphenol oxidase. Upon mixing the enzyme with the substrate and exposure to oxygen (as when a potato or apple is cut), the colorless catechol oxidizes to reddish-brown benzoquinone derivatives. The enzyme is inactivated by adding an acid, such as lemon juice, or by refrigeration. Excluding oxygen also prevents the browning reaction. Catechol melts at 28 °C and boils at 250 °C. It is employed in medicine as an expectorant. The dimethyl ether or veratrol is also used in medicine. Many other pyrocatechin derivatives have been suggested for therapeutic application. Pyrocatechol has also been found to be a microbial metabolite in Escherichia, Mycobacterium and Pseudomonas (PMID:19300498; PMID:25281236).
Pyrocatechol sulfate, also known as 1,2-benzenediol mono(hydrogen sulfate) and 2-aminophenol sulfate, is classified as a member of the class of compounds known as phenylsulfates. Phenylsulfates are compounds containing a sulfuric acid group conjugated to a phenyl group. Pyrocatechol sulfate is considered to be slightly soluble (in water) and an extremely strong acidic compound. Pyrocatechol sulfate is a benzoxazinoid metabolite. It is a potential urinary biomarker of whole grain intake (PMID: 27805021).
Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed).
Guanosine cyclic 3',5'-(hydrogen phosphate). A guanine nucleotide containing one phosphate group which is esterified to the sugar moiety in both the 3'- and 5'-positions. It is a cellular regulatory agent and has been described as a second messenger. Its levels increase in response to a variety of hormones, including acetylcholine, insulin, and oxytocin and it has been found to activate specific protein kinases. (From Merck Index, 11th ed).
Chenodeoxycholic acid 3-sulfate is produced by the action of enzymes existing in the microbial flora of the colonic environment. The major phase II metabolism of bile acids is sulfation mainly catalyzed by the hydroxysteroid sulfotransferase, forming the 3-sulfate conjugate. (PMID: 16949895).
Choline is a basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism. Choline is now considered to be an essential vitamin. While humans can synthesize small amounts (by converting phosphatidylethanolamine to phosphatidylcholine), it must be consumed in the diet to maintain health. Required levels are between 425 mg/day (female) and 550 mg/day (male). Milk, eggs, liver, and peanuts are especially rich in choline. Most choline is found in phospholipids, namely phosphatidylcholine or lecithin. Choline can be oxidized to form betaine, which is a methyl source for many reactions (i.e. conversion of homocysteine into methionine). Lack of sufficient amounts of choline in the diet can lead to a fatty liver condition and general liver damage. This arises from the lack of VLDL, which is necessary to transport fats away from the liver. Choline deficiency also leads to elevated serum levels of alanine amino transferase and is associated with increased incidence of liver cancer.
Choline is a basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism. Choline is now considered to be an essential vitamin. While humans can synthesize small amounts (by converting phosphatidylethanolamine to phosphatidylcholine), it must be consumed in the diet to maintain health. Required levels are between 425 mg/day (female) and 550 mg/day (male). Milk, eggs, liver, and peanuts are especially rich in choline. Most choline is found in phospholipids, namely phosphatidylcholine or lecithin. Choline can be oxidized to form betaine, which is a methyl source for many reactions (i.e. conversion of homocysteine into methionine). Lack of sufficient amounts of choline in the diet can lead to a fatty liver condition and general liver damage. This arises from the lack of VLDL, which is necessary to transport fats away from the liver. Choline deficiency also leads to elevated serum levels of alanine amino transferase and is associated with increased incidence of liver cancer.
Choline is a basic constituent of lecithin that is found in many plants and animal organs. It is important as a precursor of acetylcholine, as a methyl donor in various metabolic processes, and in lipid metabolism. Choline is now considered to be an essential vitamin. While humans can synthesize small amounts (by converting phosphatidylethanolamine to phosphatidylcholine), it must be consumed in the diet to maintain health. Required levels are between 425 mg/day (female) and 550 mg/day (male). Milk, eggs, liver, and peanuts are especially rich in choline. Most choline is found in phospholipids, namely phosphatidylcholine or lecithin. Choline can be oxidized to form betaine, which is a methyl source for many reactions (i.e. conversion of homocysteine into methionine). Lack of sufficient amounts of choline in the diet can lead to a fatty liver condition and general liver damage. This arises from the lack of VLDL, which is necessary to transport fats away from the liver. Choline deficiency also leads to elevated serum levels of alanine amino transferase and is associated with increased incidence of liver cancer.
Ciliatine is an organophosphorus compound isolated from human and animal tissues.
Cinnavalininate is an intermediate in the tryptophan metabolic pathway [Kegg: C05640]. It is generated from 3-hydroxyanthranilate via the enzyme catalase (EC:1.11.1.6).
cis-4-Hydroxy-D-proline belongs to the class of organic compounds known as proline and derivatives. Proline and derivatives are compounds containing proline or a derivative thereof resulting from a reaction of proline at the amino group or the carboxyl group, or from the replacement of any hydrogen of glycine by a heteroatom.
cis-Aconitic acid is an intermediate in the tricarboxylic acid cycle produced by the dehydration of citric acid. The enzyme aconitase (aconitate hydratase; EC 4.2.1.3) catalyses the stereo-specific isomerization of citrate to isocitrate via cis-aconitate in the tricarboxylic acid cycle.
Constituent of collagen and the antibiotic Telomycin (Combined Chemical Dictionary).
Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
Cotinine is an alkaloid found in tobacco (Nicotiana tabacum). Cotinine belongs to the class of organic compounds known as pyrrolidinylpyridines. Pyrrolidinylpyridines are compounds containing a pyrrolidinylpyridine ring system, which consists of a pyrrolidine ring linked to a pyridine ring. It is also the predominant human metabolite of nicotine (when nicotine is inhaled or absorbed). In humans, about 70 to 80% of nicotine that is inhaled or absorbed is converted to cotinine. This transformation involves two steps. The first is mediated by a cytochrome P450 system (mainly CYP2A6 and CYP2B6) to produce nicotine iminium ion. The second step is catalyzed by aldehyde oxidase (AOX). A number of cotinine metabolites have also been structurally characterized. Indeed, it appears that most of the reported urinary metabolites of nicotine are derived from cotinine. Cotinine is widely used as a biomarker for exposure to tobacco smoke. Cotinine has an in vivo half-life of approximately 20 hours, and is typically detectable for several days (up to one week) after the use of tobacco. Similar to nicotine, cotinine binds to, activates, and desensitizes neuronal nicotinic acetylcholine receptors, though at much lower potency in comparison. It has demonstrated nootropic and antipsychotic-like effects in animal models. Cotinine treatment has also been shown to reduce depression, anxiety, and fear-related behavior as well as memory impairment in animal models of depression, PTSD, and Alzheimer's disease.
Creatinine, or creatine anhydride, is a breakdown product of creatine phosphate in muscle. The loss of a water molecule from creatine results in the formation of creatinine. Creatinine is transferred to the kidneys by blood plasma, whereupon it is eliminated from the body by glomerular filtration and partial tubular excretion. Creatinine is usually produced at a fairly constant rate by the body. Measuring serum creatinine is a simple test and it is the most commonly used indicator of renal function. A rise in blood creatinine levels is observed only with marked damage to functioning nephrons. Therefore, this test is not suitable for detecting early kidney disease. The typical reference range for women is considered about 45-90 µmol/L; for men 60-110 µmol/L. Creatine and creatinine are metabolized in the kidneys, muscle, liver, and pancreas.
Creatinine, or creatine anhydride, is a breakdown product of creatine phosphate in muscle. The loss of a water molecule from creatine results in the formation of creatinine. Creatinine is transferred to the kidneys by blood plasma, whereupon it is eliminated from the body by glomerular filtration and partial tubular excretion. Creatinine is usually produced at a fairly constant rate by the body. Measuring serum creatinine is a simple test and it is the most commonly used indicator of renal function. A rise in blood creatinine levels is observed only with marked damage to functioning nephrons. Therefore, this test is not suitable for detecting early kidney disease. The typical reference range for women is considered about 45-90 µmol/L; for men 60-110 µmol/L. Creatine and creatinine are metabolized in the kidneys, muscle, liver, and pancreas.
Creatinine, or creatine anhydride, is a breakdown product of creatine phosphate in muscle. The loss of a water molecule from creatine results in the formation of creatinine. Creatinine is transferred to the kidneys by blood plasma, whereupon it is eliminated from the body by glomerular filtration and partial tubular excretion. Creatinine is usually produced at a fairly constant rate by the body. Measuring serum creatinine is a simple test and it is the most commonly used indicator of renal function. A rise in blood creatinine levels is observed only with marked damage to functioning nephrons. Therefore, this test is not suitable for detecting early kidney disease. The typical reference range for women is considered about 45-90 µmol/L; for men 60-110 µmol/L. Creatine and creatinine are metabolized in the kidneys, muscle, liver, and pancreas.
Cysteinylglycine is a naturally occurring dipeptide composed of cysteine and glycine. It is derived from the breakdown of glutathione (a tripeptide). In plasma, cysteinylglycine is in a reduced, oxidized, and protein-bound form (aminothiol) and interacts via redox and disulphide exchange reactions in a dynamic system referred to as redox thiol status (PMID: 8642471). Spermatozoa of sub-fertile men contain significantly higher thiol concentrations as compared with those of fertile men. The detrimental effect on embryo quality of a high homocysteine (Hcy) concentration in the ejaculate and in the follicular fluid is intriguing and may suggest that Hcy is inversely associated with fertility outcome (PMID: 16556671). Rheumatoid arthritis (RA) is a chronic inflammatory disease which involves the synovial membrane of multiple diarthroidal joints causing damage to cartilage and bones. The damage process seems to be related to an overproduction of oxygen reactive species inducing an oxidative perturbation with an increase in some oxidized forms (disulfides and protein mixed disulfides) and a decrease in free thiols (PMID: 15895891). Imipenem (thienamycin formamidine) is a broad-spectrum beta-lactam antibiotic, always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin causes plasma levels of cysteinylglycine to increase significantly, while cysteine levels are decreased and homocysteine levels are unaffected. Therefore, antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized (PMID: 15843241).
Cysteinylglycine is a naturally occurring dipeptide composed of cysteine and glycine. It is derived from the breakdown of glutathione (a tripeptide). In plasma, cysteinylglycine is in a reduced, oxidized, and protein-bound form (aminothiol) and interacts via redox and disulphide exchange reactions in a dynamic system referred to as redox thiol status (PMID: 8642471). Spermatozoa of sub-fertile men contain significantly higher thiol concentrations as compared with those of fertile men. The detrimental effect on embryo quality of a high homocysteine (Hcy) concentration in the ejaculate and in the follicular fluid is intriguing and may suggest that Hcy is inversely associated with fertility outcome (PMID: 16556671). Rheumatoid arthritis (RA) is a chronic inflammatory disease which involves the synovial membrane of multiple diarthroidal joints causing damage to cartilage and bones. The damage process seems to be related to an overproduction of oxygen reactive species inducing an oxidative perturbation with an increase in some oxidized forms (disulfides and protein mixed disulfides) and a decrease in free thiols (PMID: 15895891). Imipenem (thienamycin formamidine) is a broad-spectrum beta-lactam antibiotic, always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin causes plasma levels of cysteinylglycine to increase significantly, while cysteine levels are decreased and homocysteine levels are unaffected. Therefore, antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized (PMID: 15843241).
Cysteinyl-Proline is a dipeptide composed of cysteine and proline. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
Cysteinyl-Proline is a dipeptide composed of cysteine and proline. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
Cysteamine is a product of the constitutive degradation of coenzyme A, a process that occurs in all tissues, although some tissues such as brain and heart may have exceptionally high coenzyme A turnover rates. Cysteamine has only one known function, and that is as a precursor for the formation of hypotaurine, which is subsequently oxidized to taurine. The rate of cysteamine production as a result of coenzyme A breakdown is not well understood but it is clear that cysteamine levels are not as dramatically affected by dietary habits as are cysteine levels. Cysteamine is generated from hypotaurine by cysteamine dioxygenase (EC:1.13.11.19), an enzyme that was recently identified in mammals (PMID:17581819). Cysteamine is the simplest stable aminothiol found in the body. It is used in the treatment of disorders of cystine excretion. Cysteamine cleaves the disulfide bond with cysteine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria. Cyst(e)amine may also serve as an endogenous regulator of immune system activity as well as a potential therapeutic agent for the treatment of Huntington disease. Cysteamine is also used as a radiation-protective agent that oxidizes in air to form cystamine. It can be given intravenously or orally to treat radiation sickness.
Cysteamine is a product of the constitutive degradation of coenzyme A, a process that occurs in all tissues, although some tissues such as brain and heart may have exceptionally high coenzyme A turnover rates. Cysteamine has only one known function, and that is as a precursor for the formation of hypotaurine, which is subsequently oxidized to taurine. The rate of cysteamine production as a result of coenzyme A breakdown is not well understood but it is clear that cysteamine levels are not as dramatically affected by dietary habits as are cysteine levels. Cysteamine is generated from hypotaurine by cysteamine dioxygenase (EC:1.13.11.19), an enzyme that was recently identified in mammals (PMID:17581819). Cysteamine is the simplest stable aminothiol found in the body. It is used in the treatment of disorders of cystine excretion. Cysteamine cleaves the disulfide bond with cysteine to produce molecules that can escape the metabolic defect in cystinosis and cystinuria. Cyst(e)amine may also serve as an endogenous regulator of immune system activity as well as a potential therapeutic agent for the treatment of Huntington disease. Cysteamine is also used as a radiation-protective agent that oxidizes in air to form cystamine. It can be given intravenously or orally to treat radiation sickness.
Cysteineglutathione disulfide is a molecule that is formed upon oxidative stress of glutathione, that will form mixed disulfides with protein thiol groups, causing reversible S-glutathionylation. S-glutathionylation is an important post-translational modification responsible for transducing oxidant signals. S-glutathionylation of thiols confers protection against their irreversible oxidation, like for instance the formation of sulphonic acid moieties. If the targeted cysteine is a functionally critical amino acid, S-glutathionylation will however also modify protein function. (PMID 16515838). S-sulfonation and S-thiolation of transthyretin Phe33Cys has been detected in a patient with familial transthyretin amyloidosis. (PMID 12876326). In Cystinotic human skin fibroblasts in tissue culture there is an accumulation of cystine. Stored cystine in cystinotic tissues may derive in part from glutathione-cysteine mixed disulfide via transpeptidation. (PMID 6130452). Cystinosis is an autosomal recessive disorder caused by an impaired transport of cystine out of lysosomes. (PMID 15042893).
Cysteineglutathione disulfide is a molecule that is formed upon oxidative stress of glutathione, that will form mixed disulfides with protein thiol groups, causing reversible S-glutathionylation. S-glutathionylation is an important post-translational modification responsible for transducing oxidant signals. S-glutathionylation of thiols confers protection against their irreversible oxidation, like for instance the formation of sulphonic acid moieties. If the targeted cysteine is a functionally critical amino acid, S-glutathionylation will however also modify protein function. (PMID 16515838). S-sulfonation and S-thiolation of transthyretin Phe33Cys has been detected in a patient with familial transthyretin amyloidosis. (PMID 12876326). In Cystinotic human skin fibroblasts in tissue culture there is an accumulation of cystine. Stored cystine in cystinotic tissues may derive in part from glutathione-cysteine mixed disulfide via transpeptidation. (PMID 6130452). Cystinosis is an autosomal recessive disorder caused by an impaired transport of cystine out of lysosomes. (PMID 15042893).
Cysteinylglycine is a naturally occurring dipeptide composed of cysteine and glycine. It is derived from the breakdown of glutathione (a tripeptide). In plasma, cysteinylglycine is in a reduced, oxidized, and protein-bound form (aminothiol) and interacts via redox and disulphide exchange reactions in a dynamic system referred to as redox thiol status (PMID: 8642471). Spermatozoa of sub-fertile men contain significantly higher thiol concentrations as compared with those of fertile men. The detrimental effect on embryo quality of a high homocysteine (Hcy) concentration in the ejaculate and in the follicular fluid is intriguing and may suggest that Hcy is inversely associated with fertility outcome (PMID: 16556671). Rheumatoid arthritis (RA) is a chronic inflammatory disease which involves the synovial membrane of multiple diarthroidal joints causing damage to cartilage and bones. The damage process seems to be related to an overproduction of oxygen reactive species inducing an oxidative perturbation with an increase in some oxidized forms (disulfides and protein mixed disulfides) and a decrease in free thiols (PMID: 15895891). Imipenem (thienamycin formamidine) is a broad-spectrum beta-lactam antibiotic, always used in combination with cilastatin in order to avoid the premature breakdown of imipenem by renal tubular dipeptidase. As this dipeptidase also hydrolyzes the glutathione metabolite cysteinylglycine, the therapeutic association of imipenem and cilastatin causes plasma levels of cysteinylglycine to increase significantly, while cysteine levels are decreased and homocysteine levels are unaffected. Therefore, antibiotic treatment using imipenem-cilastatin induces important metabolic changes that should not remain unrecognized (PMID: 15843241).
Cytidine is a nucleoside that is composed of the base cytosine linked to the five-carbon sugar D-ribose. Cytidine is a pyrimidine that besides being incorporated into nucleic acids, can serve as a substrate for the salvage pathway of pyrimidine nucleotide synthesis. It is a precursor of cytidine triphosphate (CTP) needed in the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthetic pathways. These variations probably reflect the species differences in cytidine deaminase, the enzyme that converts cytidine to uridine in the body. The transport of cytidine into the brain's extracellular fluid, and then into neurons and glia, are essential prerequisites for cytidine to be utilized in the brain. An efficient mechanism mediating the brain uptake of circulating cytidine has not yet been demonstrated. The biosynthesis of PC, the most abundant phosphatide in the brain, via the Kennedy pathway requires phosphocholine and cytidine triphosphate (CTP), a cytidine nucleotide involved in the rate-limiting step. The enzyme that converts CTP to endogenous CDP-choline (CTP:phosphocholine cytidylyltransferase) is unsaturated at physiological brain CTP levels. APOBEC is a family of enzymes that has been discovered with the ability to deaminate cytidines on RNA or DNA. The human apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G protein (APOBEC3G, or hA3G), provides cells with an intracellular antiretroviral activity that is associated with the hypermutation of viral DNA through cytidine deamination. Indeed, hA3G belongs to a family of vertebrate proteins that contains one or two copies of a signature sequence motif unique to cytidine deaminases (CTDAs) (PMID: 16769123, 15780864, 16720547).
Cytidine 2',3'-cyclic phosphate is a cytidine nucleotide containing a pyrophosphate group esterified to C2 and C3(cyclic) of the sugar moiety. A cyclic nucleotide is any nucleotide in which the phosphate group is bonded to two of the sugar's hydroxyl groups, forming a cyclical or ring structure. 2',3' cyclic CMP is a substrate for 2',3'-cyclic-nucleotide 3'-phosphodiesterase (EC 3.1.4.37). This enzyme (also called CNP) catalyzes the chemical reaction: nucleoside 2',3'-cyclic phosphate + H2O <-> nucleoside 2'-phosphate. CNP is a myelin-associated enzyme that makes up 4% of total CNS myelin protein, and is thought to undergo significant age-associated changes. The absence of CNP causes axonal swelling and neuronal degeneration. The biological role of cyclic 2',3' monophosphates is not clear, although it is thought to have something to do with neuronal stasis or development.
Cytosine, also known as C, belongs to the class of organic compounds known as pyrimidones. Pyrimidones are compounds that contain a pyrimidine ring, which bears a ketone. Pyrimidine is a 6-membered ring consisting of four carbon atoms and two nitrogen centers at the 1- and 3- ring positions. Cytosine is also classified as a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, cytosine forms three hydrogen bonds with guanine. Cytosine was discovered and named by Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues. Cytosine exists in all living species, ranging from bacteria to plants to humans. Within cells, cytosine can undergo several enzymatic reactions. It can be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase (DNMT) or be methylated and hydroxylated to make 5-hydroxymethylcytosine. The DNA methyltransferase (DNMT) family of enzymes transfer a methyl group from S-adenosyl-l-methionine (SAM) to the 5‚Äô carbon of cytosine in a molecule of DNA. High levels of cytosine can be found in the urine of individuals with severe combined immunodeficiency syndrome (SCID). Cytosine concentrations as high as (23-160 mmol/mol creatinine) were detected in SCID patients compared to normal levels of <2 mmol/mol creatinine (PMID: 262183).
Cytosine, also known as C, belongs to the class of organic compounds known as pyrimidones. Pyrimidones are compounds that contain a pyrimidine ring, which bears a ketone. Pyrimidine is a 6-membered ring consisting of four carbon atoms and two nitrogen centers at the 1- and 3- ring positions. Cytosine is also classified as a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a keto group at position 2). Cytosine is one of the four main bases found in DNA and RNA, along with adenine, guanine, and thymine (uracil in RNA). The nucleoside of cytosine is cytidine. In Watson-Crick base pairing, cytosine forms three hydrogen bonds with guanine. Cytosine was discovered and named by Albrecht Kossel and Albert Neumann in 1894 when it was hydrolyzed from calf thymus tissues. Cytosine exists in all living species, ranging from bacteria to plants to humans. Within cells, cytosine can undergo several enzymatic reactions. It can be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase (DNMT) or be methylated and hydroxylated to make 5-hydroxymethylcytosine. The DNA methyltransferase (DNMT) family of enzymes transfer a methyl group from S-adenosyl-l-methionine (SAM) to the 5‚Äô carbon of cytosine in a molecule of DNA. High levels of cytosine can be found in the urine of individuals with severe combined immunodeficiency syndrome (SCID). Cytosine concentrations as high as (23-160 mmol/mol creatinine) were detected in SCID patients compared to normal levels of <2 mmol/mol creatinine (PMID: 262183).
Cellobiose, also known as GLCB1-4GLCB or cellose, is a disaccharide. It is also classified as a reducing sugar. In terms of its chemical structure, it is derived from the condensation of a pair beta-glucose molecules creating a beta (1‚Üí4) bond. It belongs to the class of organic compounds known as O-glycosyl compounds. These are glycosides in which a sugar group is bonded through one carbon to another group via a O-glycosidic bond. Cellobiose can be obtained by enzymatic hydrolysis of cellulose and cellulose-rich materials such as cotton, jute, or paper. Cellobiose is a plant metabolite found in flowering plants, conifers and other gymnosperms. Cellobiose can also be found in vertebrates that have consumed plant foods. It has been detected, but not quantified in, several different foods, such as okra, common chokecherries, cherry tomatoes, and welsh onions. Cellobiose can be used as an indicator carbohydrate for Crohn's disease and malabsorption syndrome. Intestinal permeability to detect Crohn's disease and malabsorption syndrome can be measured by the sugar absorption test. This test is based on determining the ratio of the urinary excretion of a large (a disaccharide such as cellobiose) and a small carbohydrate (a monosaccharide such as lactulose or rhamnose) after oral administration. Patients with Crohn's disease or with ulcerative colitis have increased permeability indices in comparison to healthy controls (PMID: 15546811).
Alanine is a nonessential amino acid made in the body from the conversion of the carbohydrate pyruvate or the breakdown of DNA and the dipeptides carnosine and anserine. It is highly concentrated in muscle and is one of the most important amino acids released by muscle, functioning as a major energy source. Plasma alanine is often decreased when the BCAA (Branched Chain Amino Acids) are deficient. This finding may relate to muscle metabolism. Alanine is highly concentrated in meat products and other high-protein foods like wheat germ and cottage cheese. Alanine is an important participant as well as regulator in glucose metabolism. Alanine levels parallel blood sugar levels in both diabetes and hypoglycemia, and alanine reduces both severe hypoglycemia and the ketosis of diabetes. It is an important amino acid for lymphocyte reproduction and immunity. Alanine therapy has helped dissolve kidney stones in experimental animals. Normal alanine metabolism, like that of other amino acids, is highly dependent upon enzymes that contain vitamin B6. Alanine, like GABA, taurine and glycine, is an inhibitory neurotransmitter in the brain. Alanine can be found in some Gram-positive bacteria (PMID:24752840).
Fructose 1-phosphate, also known as D-fructose-1-p, belongs to the class of organic compounds known as hexose phosphates. These are carbohydrate derivatives containing a hexose substituted by one or more phosphate groups. Metabolism of fructose thus essentially results in intermediates of glycolysis. The final product of glycolysis (pyruvate) may then undergo gluconeogenesis, enter the TCA cycle or be stored as fatty acids. Fructose 1-phosphate exists in all living organisms, ranging from bacteria to humans. Within humans, fructose 1-phosphate participates in a number of enzymatic reactions. In particular, fructose 1-phosphate can be biosynthesized from D-fructose through the action of the enzyme ketohexokinase. In addition, fructose 1-phosphate can be converted into dihydroxyacetone phosphate and glyceraldehyde; which is catalyzed by the enzyme fructose-bisphosphate aldolase a. Because fructokinase has a high Vmax fructose entering cells is quickly phosphorylated to fructose 1-phosphate. In humans, fructose 1-phosphate is involved in fructose intolerance, hereditary. Hypoglycemia results from inhibition of glycogenolysis and gluconeogenesis. It is generated mainly by hepatic fructokinase but is also generated in smaller amounts in the small intestinal mucosa and proximal epithelium of the renal tubule. Aldolase B converts it into glyceraldehyde and dihydroxyacetone phosphate (DHAP). Symptoms of hereditary fructose intolerance are apathy, drowsiness, sweatiness and tremulousness.
Fructose 6-phosphate (F6P) belongs to the class of organic compounds known as hexose phosphates. These are carbohydrate derivatives containing a hexose substituted by one or more phosphate groups. F6P is a derivative of fructose, which has been phosphorylated at the 6-hydroxy group. Fructose 6-phosphate is a fundamental metabolite and exists in all living species, ranging from bacteria to plants to humans. The great majority of glucose is converted to fructose 6-phosphate as part of the glycolytic metabolic pathway (glycolysis). Specifically, F6P is produce is produced by the isomerisation of glucose 6-phosphate via the enzyme phosphoglucose isomerase. F6P is in turn further phosphorylated to fructose-1,6-bisphosphate by the enzyme phosphofructokinase-1. Glycolysis is the metabolic pathway that converts glucose into pyruvic acid. The free energy released in this process is used to form ATP and reduced nicotinamide adenine dinucleotide (NADH). In addition to its key involvement in glycolysis, fructose 6-phosphate can also be biosynthesized from glucosamine 6-phosphate via the enzyme glucosamine-6-phosphate isomerase 1. In addition, fructose 6-phosphate and L-glutamine can be converted into glucosamine 6-phosphate and L-glutamic acid through the action of the enzyme glutamine--fructose-6-phosphate aminotransferase.
Glucosamine 6-phosphate (CAS: 3616-42-0) is normally produced in endothelial cells via de novo glucosamine synthesis by the enzyme fructose-6-phosphate amidotransferase and the modulation of this pathway by hyperglycemia and glutamine. Glutamine-fructose-6-phosphate amidotransferase (GFAT) catalyzes the first committed step in the pathway for biosynthesis of hexosamines in mammals.It is a member of the N-terminal nucleophile class of amidotransferases, GFAT transfers the amino group from the L-glutamine amide to D-fructose 6-phosphate, producing glutamic acid and glucosamine 6-phosphate. As glucosamine inhibits endothelial nitric oxide synthesis it has important implications for impaired endothelium-dependent relaxation and vascular dysfunction in diabetes mellitus (PMID:11270676, 11842094).
Glucuronic acid (CAS: 6556-12-3) is a carboxylic acid that has the structure of a glucose molecule that has had its sixth carbon atom (of six total) oxidized. The salts of glucuronic acid are known as glucuronates. Glucuronic acid is highly soluble in water. In humans, glucuronic acid is often linked to toxic or poisonous substances to allow for subsequent elimination, and to hormones to allow for easier transport. These linkages involve O-glycosidic bonds. The process is known as glucuronidation, and the resulting substances are known as glucuronides (or glucuronosides). Glucuronidation uses UDP-glucuronic acid (glucuronic acid linked via a glycosidic bond to uridine diphosphate) as an intermediate. UDP-glucuronic acid is formed in the liver of all animals.
Mannose 6-phosphate, also known as alpha-D-mannose-6-p or man-6-p, belongs to the class of organic compounds known as hexose phosphates. These are carbohydrate derivatives containing a hexose substituted by one or more phosphate groups. Mannose 6-phosphate exists in all eukaryotes, ranging from yeast to humans. Within humans, mannose 6-phosphate participates in a number of enzymatic reactions. In particular, mannose 6-phosphate can be converted into fructose 6-phosphate through its interaction with the enzyme mannose-6-phosphate isomerase. In addition, mannose 6-phosphate can be biosynthesized from D-mannose through the action of the enzyme hexokinase-1. Mannose 6-phosphate is a potent competitive inhibitor of pinocytosis of human platelet beta-glucuronidase and it is a necessary component of the recognition marker on the enzyme for pinocytosis by human fibroblasts as well (PMID 908752). In humans, mannose 6-phosphate is involved in fructose intolerance, hereditary.
Phytosphingosine-1-P is an intermediate in sphingolipid metabolism pathway. It is the enzymatic oxidation product of 4-hydroxysphinganine. Sphingolipids are essential components of the plasma membrane in all eukaryotic cells. S. cerevisiae cells make three complex sphingolipids: inositol-phosphoceramide (IPC), mannose-inositol-phosphoceramide (MIPC), and mannosyl-diinositol-phosphorylceramide (M(IP)2C) [ Dickson02 ]. In the yeast plasma membrane sphingolipids concentrate with ergosterol to form lipid rafts, specialized membrane microdomains implicated in a variety of cellular processes, including sorting of membrane proteins and lipids, as well as organizing and regulating signaling cascades [ Bagnat02 ]. Intermediates in sphingolipid biosynthesis have been shown to play important roles as signaling molecules and growth regulators. Sphingolipid long chain bases (LCBs), dihydrosphingosine (DHS) and phytosphingosine (PHS), have been implicated as secondary messengers in signaling pathways that regulate heat stress response. Other intermediates, phytoceramide and long-chain base phosphates (LCBPs), have been shown to be components of tightly-controlled ceramide/LCBP rheostat, which regulates cell growth. Since phosphoinositol-containing sphingolipids are unique to fungi, the sphingolipid biosynthesis pathway is considered a target for antifungal drugs.
Glucaric acid, also known as glucarate or D-saccharic acid, belongs to the class of organic compounds known as glucuronic acid derivatives. Glucuronic acid derivatives are compounds containing a glucuronic acid moiety (or a derivative), which consists of a glucose moiety with the C6 carbon oxidized to a carboxylic acid. Glucaric acid is a sugar acid derived from D-glucose in which both the aldehydic carbon atom and the carbon atom bearing the primary hydroxyl group are oxidized to carboxylic acid groups. D-glucaric acid is found in fruits, vegetables, and mammals. The highest concentrations of glucaric acid are found in grapefruits, apples, oranges, and cruciferous vegetables (PMID: 18772850). Glucaric acid is produced through the oxidation of glucose. Cytochrome P450 is thought to be responsible for the production of D-glucaric acid in vivo (PMID: 3779687). In mammals, D-glucaric acid and D-glucaro-l,4-lactone are also known end-products of the D-glucuronic acid pathway (PMID: 18772850). Glucaric is available as a dietary supplement in the form of calcium D-glucarate and has been studied for therapeutic purposes including cholesterol reduction and cancer chemotherapy (PMID: 9101079). D-Glucaric acid has a potential use as a building block for a number of polymers, including new nylons and hyperbranched polyesters. D-glucaric acid produced from D-glucose has been successfully utilized to produce a hydroxylated nylon.
Tryptophan (Trp or W) (sold for medical use as Tryptan) is one of the 20 standard amino acids. Its distinguishing structural characteristic is its indole functional group. The D-stereoisomer is occasionally found in naturally produced peptides (e.g. contryphan, the marine venom peptide).
Mannitol, or hexan-1,2,3,4,5,6-hexol (C6H8(OH)6), is an alcohol and a sugar (sugar alcohol), or a polyol, it is a stereoisomer of sorbitol and is similar to the C5 xylitol. The structure of mannitol is made of a straight chain of six carbon atoms, each of which is substituted with a hydroxyl group. Mannitol is one of the most abundant energy and carbon storage molecules in nature, it is produced by a wide range of organisms such as bacteria, fungi and plants (PMID: 19578847). In medicine, mannitol is used as a diuretic and renal diagnostic aid. Mannitol has little significant energy value as it is largely eliminated from the body before any metabolism can take place. It can be used to treat oliguria associated with kidney failure or other manifestations of inadequate renal function and has been used for determination of glomerular filtration rate. Mannitol is also commonly used as a research tool in cell biological studies, usually to control osmolarity. Mannitol has a tendency to lose a hydrogen ion in aqueous solutions, which causes the solution to become acidic. For this, it is not uncommon to add a weak base, such as sodium bicarbonate, to the solution to adjust its pH. Mannitol is a non-permeating molecule i.e., it cannot cross biological membranes. Mannitol is an osmotic diuretic agent and a weak renal vasodilator. Mannitol is found to be associated with cytochrome c oxidase deficiency and ribose-5-phosphate isomerase deficiency, which are inborn errors of metabolism. Mannitol is also a microbial metabolite found in Aspergillus, Candida, Clostridium, Gluconobacter, Lactobacillus, Lactococcus, Leuconostoc, Pseudomonas, Rhodobacteraceae, Saccharomyces, Streptococcus, Torulaspora and Zymomonas (PMID: 15240312; PMID: 29480337).
Ribonolactone, also known as D-ribono-1,4-lactone is a five-membered form of ribonolactone having D-configuration. It has a role as a metabolite. It is a ribonolactone and a butan-4-olide. It derives from a D-ribonic acid. Ribonolactone belongs to the class of organic compounds known as pentoses. These are monosaccharides in which the carbohydrate moiety contains five carbon atoms. Ribonolactone is a metabolite normally not detectable in human biofluids; however, it has been found in the urine of patients with neuroblastoma.
Deoxycytidine triphosphate (dCTP) is a cytidine nucleotide triphosphate that is used whenever DNA is synthesized, such as in the polymerase chain reaction. e.g.:.
Imidazolepropionic acid, also known as deaminohistidine or 4-imidazolylpropionate, belongs to the class of organic compounds known as imidazolyl carboxylic acids and derivatives. These are organic compounds containing a carboxylic acid chain (of at least 2 carbon atoms) linked to an imidazole ring. Imidazolepropionic acid is a very strong basic compound (based on its pKa). Imidazolepropionic acid is a product of histidine metabolism which may involve oxidation or transamination. This compound is found in the urine of rats loaded with histidine (PMID: 6021220).
dGDP is a derivative of the common nucleic acid GTP, or guanosine triphosphate, in which the -OH (hydroxyl) group on the 2' carbon on the nucleotide's pentose has been removed (hence the deoxy- part of the name). Additionally, the diphosphate of the name indicates that one of the phosphoryl groups of GTP has been removed, most likely by hydrolysis (Wikipedia).
dGDP is a derivative of the common nucleic acid GTP, or guanosine triphosphate, in which the -OH (hydroxyl) group on the 2' carbon on the nucleotide's pentose has been removed (hence the deoxy- part of the name). Additionally, the diphosphate of the name indicates that one of the phosphoryl groups of GTP has been removed, most likely by hydrolysis (Wikipedia).
Deoxyguanosine triphosphate (dGTP) is a nucleoside triphosphate, and a nucleotide precursor used in cells for DNA synthesis. dGTP is used in the polymerase chain reaction technique, in sequencing, and in cloning. It is also the competitor of inhibition onset by acyclovir in the treatment of HSV virus. Under normal physiologic conditions, deoxyguanosine (dGuo) undergoes phosphorolysis by purine nucleoside phosphorylase (PNP, EC 2.4.2.1, an enzyme involved in the recycling of nucleosides and deoxynucleosides in cellular remodeling). However, when PNP is inhibited, deoxycytidine kinase (dCK, EC 2.7.1.74) shunts unmetabolized dGuo into deoxyguanosine triphosphate (dGTP), which accumulates and blocks DNA synthesis. Deficiency of purine nucleoside phosphorylase results in defective T-cell immunity. A correlation between the degree of T cell inhibition and the level of dCK activity has been observed. (PMID:11287638, 402573).
3-Methoxy-4-Hydroxyphenylglycol sulfate, also known as (3-methoxy-4-sulfonyloxyphenyl)glycol or MHPG-sulfate, belongs to the class of organic compounds known as methoxyphenols. Methoxyphenols are compounds containing a methoxy group attached to the benzene ring of a phenol moiety. 3-Methoxy-4-Hydroxyphenylglycol sulfate is a member of phenols and an alcohol.
Dimethylglycine (DMG) is an amino acid derivative found in the cells of all plants and animals and can be obtained in the diet in small amounts from grains and meat. The human body produces DMG when metabolizing choline into glycine. Dimethylglycine that is not metabolized in the liver is transported by the circulatory system to body tissue. Dimethylglycine was popular with Russian athletes and cosmonauts owing to its reputed ability to increase endurance and reduce fatigue. DMG is also a byproduct of homocysteine metabolism. Homocysteine and betaine are converted to methionine and N,N-dimethylglycine by betaine-homocysteine methyltransferase. DMG in the urine is a biomarker for the consumption of legumes. It is also a microbial metabolite (PMID: 25901889).
Dimethylmalonic acid is a dicarboxylic acid that is malonic acid in which both methylene hydrogens have been replaced by methyl groups. It has a role as a fatty acid synthesis inhibitor. Dimethylmalonic acid, also known as 2,2-dimethylmalonate or propanedioate, belongs to the class of organic compounds known as dicarboxylic acids and derivatives. These are organic compounds containing exactly two carboxylic acid groups. Dimethylmalonic acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral.
Dityrosine is a fluorescent molecule formed as a result of normal posttranslational processing. In many structural proteins, dityrosine confers resistance to proteolysis and physicochemical trauma as a stabilizing crosslink. Dityrosine has also been found in oxidative/nitrative stress under a variety of conditions and biological systems. In this regard, it has been used as an important biomarker for oxidatively modified proteins during UV and gamma-irradiation, aging, and exposure to oxygen free radicals, nitrogen dioxide, peroxynitrite, and lipid hydroperoxides. Renewed interest in dityrosine and other tyrosine oxidation products as clinical indicators of oxidative modification has driven the development of important techniques for the specific analysis and quantification of these molecules. The presence of elevated levels of dityrosine in mammalian tissue and urine samples has been measured by chromatographic separation followed by mass spectrometry GC-MS and HPLC-MS/MS. Increases in dityrosine levels have been associated with pathologies such as eye cataracts, atherosclerosis, acute inflammation, and Alzheimer's disease. The continued development of, and increased accessibility to, improved mass spectrometric instrumentation will expand the capability, feasibility, and sensitivity with which specific biomarkers like dityrosine can be measured. (PMID: 17019703).
Dopamine 3-O-sulfate is a sulfonated form of dopamine. In human blood circulation endogenous dopamine exists predominantly in the sulfated form and dopamine sulfate accounts for more than 90% of all dopamine. Dopamine-3-O-sulfate predominates in human plasma, with concentrations about 10-fold higher than those of the regioisomer dopamine-4-O-sulfate. Sulfonation is the most important metabolic pathway that interferes with the binding of dopamine to its receptors. The origins of this preponderance for Dopamine-3-O-sulfate have not been determined, although there has been speculation about the contribution of the specificity of transport proteins and/or arylsulfatases. It has also been proposed to depend on the regiospecificity of the metabolizing enzyme(s) for the 3-hydroxy group of dopamine. It is believed that the vast majority of circulating dopamine sulfate originates in the upper gastrointestinal tract, and indeed that is the main site of expression of the enzyme responsible for its formation. Aryl sulfotransferase (SULT1A3, EC 2.8.2.1) is an enzyme that catalyzes the sulfonation of many endogenous and exogenous phenols and catechols; the most important endogenous substrate is dopamine. SULT1A3 strongly favors the 3-hydroxy group of dopamine over the 4-hydroxy group and may indeed be primarily responsible for the difference between the circulating levels of dopamine sulfates in human blood. (PMID: 17548063).
Deoxyuridine triphosphate (dUTP) is a deoxynucleotide triphosphate (dNTP) that is chemically similar to uridine triphosphate (UTP) except that it has a deoxyribose sugar instead of a ribose sugar. DNA synthesis requires the availability of deoxynucleotide triphosphates (dTTP, dATP, dGTP, dCTP), whereas RNA synthesis requires the availability of nucleotide triphosphates (NTPs) such as TTP, ATP, GTP, and UTP. The conversion of nucleotide triphosphates (NTPs) into dNTPs can only be done in the diphosphate form. Typically, an NTP has one phosphate removed to become an NDP. This is then converted into a dNDP by an enzyme called ribonucleotide reductase and followed by the re-addition of phosphate to give a dNTP. dUTP is a substrate for several enzymes, including inosine triphosphate pyrophosphatase, deoxyuridine 5'-triphosphate nucleotidohydrolase (mitochondrial), uridine-cytidine kinase 1, nucleoside diphosphate kinase 3, nucleoside diphosphate kinase B, nucleoside diphosphate kinase 6, nucleoside diphosphate kinase (mitochondrial), nucleoside diphosphate kinase homolog 5, nucleoside diphosphate kinase A, and nucleoside diphosphate kinase 7. While UTP is routinely incorporated into RNA, dUTP is not normally incorporated into DNA. Instead, if dUTP is misincorporated into DNA, it can cause DNA damage. Therefore, dUTP can be considered as a teratogen or a mutagen. The extent of DNA damage caused by dUTP is highly dependent on the levels of the dUTP pyrophosphatase (dUTPase) and uracil-DNA glycosylase (UDG), which limits the intracellular accumulation of dUTP. Additionally, loss of viability following thymidylate synthase (TS) inhibition occurs as a consequence of the accumulation of dUTP in some cell lines and subsequent misincorporation of uracil into DNA (PMID: 11487279).
Ectoine belongs to the class of organic compounds known as alpha-amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Ectoine has been identified in urine (PMID: 22409530).
Ectoine belongs to the class of organic compounds known as alpha-amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Ectoine has been identified in urine (PMID: 22409530).
Ectoine belongs to the class of organic compounds known as alpha-amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). Ectoine has been identified in urine (PMID: 22409530).
(+)-Epicatechin is found in apple. (+)-Epicatechin or ent-Epicatechin is one of the 4 catechin diastereoisomers.
Epinephrine is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. It is the active sympathomimetic hormone secreted from the adrenal medulla in most species. It stimulates both the alpha- and beta- adrenergic systems, causes systemic vasoconstriction and gastrointestinal relaxation, stimulates the heart, and dilates bronchi and cerebral vessels. It is used in asthma and cardiac failure and to delay absorption of local anesthetics. Epinephrine also constricts arterioles in the skin and gut while dilating arterioles in leg muscles. It elevates the blood sugar level by increasing hydrolysis of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in adipocytes. Epinephrine has a suppressive effect on the immune system.
Erythritol is a sugar alcohol (or polyol), used as a food additive and sugar substitute. It is naturally occurring and is made from corn using enzymes and fermentation. Its formula is C4H10O4, or HO(CH2)(CHOH)2(CH2)OH; specifically, one particular stereoisomer with that formula. Erythritol is 60–70% as sweet as sucrose (table sugar), yet it is almost noncaloric and does not affect blood sugar or cause tooth decay. Erythritol occurs widely in nature and has been found to occur naturally in several foods including wine, sake, beer, watermelon, pear, grape, and soy sauce. Evidence indicates that erythritol also exists endogenously in the tissues and body fluids of humans and animals. Erythritol is absorbed from the proximal intestine by passive diffusion in a manner similar to that of many low molecular weight organic molecules which do not have associated active transport systems. The rate of absorption is related to their molecular size. It passes through the intestinal membranes at a faster rate than larger molecules such as mannitol or glucose. In diabetics, erythritol has also been shown to be rapidly absorbed and excreted unchanged in the urine. Following absorption, ingested erythritol is rapidly distributed throughout the body and has been reported to occur in hepatocytes, pancreatic cells, and vascular smooth muscle cells. Erythritol also has been reported to cross the human placenta and to pass slowly from the plasma into the brain and cerebrospinal fluid (PMID:9862657). Erythritol is found to be associated with ribose-5-phosphate isomerase deficiency, which is an inborn error of metabolism.
Erythritol is a sugar alcohol (or polyol), used as a food additive and sugar substitute. It is naturally occurring and is made from corn using enzymes and fermentation. Its formula is C4H10O4, or HO(CH2)(CHOH)2(CH2)OH; specifically, one particular stereoisomer with that formula. Erythritol is 60–70% as sweet as sucrose (table sugar), yet it is almost noncaloric and does not affect blood sugar or cause tooth decay. Erythritol occurs widely in nature and has been found to occur naturally in several foods including wine, sake, beer, watermelon, pear, grape, and soy sauce. Evidence indicates that erythritol also exists endogenously in the tissues and body fluids of humans and animals. Erythritol is absorbed from the proximal intestine by passive diffusion in a manner similar to that of many low molecular weight organic molecules which do not have associated active transport systems. The rate of absorption is related to their molecular size. It passes through the intestinal membranes at a faster rate than larger molecules such as mannitol or glucose. In diabetics, erythritol has also been shown to be rapidly absorbed and excreted unchanged in the urine. Following absorption, ingested erythritol is rapidly distributed throughout the body and has been reported to occur in hepatocytes, pancreatic cells, and vascular smooth muscle cells. Erythritol also has been reported to cross the human placenta and to pass slowly from the plasma into the brain and cerebrospinal fluid (PMID:9862657). Erythritol is found to be associated with ribose-5-phosphate isomerase deficiency, which is an inborn error of metabolism.
Erythronic acid is a sugar component of aqueous humour (eye). It may be derived from glycated proteins or from degradation of ascorbic acid. Erythronic acid is a normal organic acid present in a healthy adult and pediatric population. It has been found in urine, plasma, CSF, and synovial fluid (PMID: 14708889, 8087979, 8376520, 10420182). Erythronic acid is formed when N-acetyl-D-glucosamine (GlcNAc) is oxidized. GlcNAc is a constituent of hyaluronic acid (HA), a polysaccharide consisting of alternating units of glucuronic acid and GlcNAc, present as an aqueous solution in synovial fluid. In the synovial fluid of patients suffering from rheumatoid arthritis, HA is thought to be degraded either by radicals generated by Fenton chemistry (Fe2+/H2O2) or by NaOCl generated by myeloperoxidase (PMID: 10614067).
Erythronic acid is a sugar component of aqueous humour (eye). It may be derived from glycated proteins or from degradation of ascorbic acid. Erythronic acid is a normal organic acid present in a healthy adult and pediatric population. It has been found in urine, plasma, CSF, and synovial fluid (PMID: 14708889, 8087979, 8376520, 10420182). Erythronic acid is formed when N-acetyl-D-glucosamine (GlcNAc) is oxidized. GlcNAc is a constituent of hyaluronic acid (HA), a polysaccharide consisting of alternating units of glucuronic acid and GlcNAc, present as an aqueous solution in synovial fluid. In the synovial fluid of patients suffering from rheumatoid arthritis, HA is thought to be degraded either by radicals generated by Fenton chemistry (Fe2+/H2O2) or by NaOCl generated by myeloperoxidase (PMID: 10614067).
Ethyl glucuronide is a natural human metabolite of Ethanol generated in the liver by UDP glucuonyltransferase. Glucuronidation is used to assist in the excretion of toxic substances, drugs or other substances that cannot be used as an energy source. Glucuronic acid is attached via a glycosidic bond to the substance, and the resulting glucuronide, which has a much higher water solubility than the original substance, is eventually excreted by the kidneys. Ethyl glucuronide is a general biomarker for the consumption of alcohol
Ethyl glucuronide is a natural human metabolite of Ethanol generated in the liver by UDP glucuonyltransferase. Glucuronidation is used to assist in the excretion of toxic substances, drugs or other substances that cannot be used as an energy source. Glucuronic acid is attached via a glycosidic bond to the substance, and the resulting glucuronide, which has a much higher water solubility than the original substance, is eventually excreted by the kidneys. Ethyl glucuronide is a general biomarker for the consumption of alcohol
trans-Ferulic acid is a highly abundant phenolic phytochemical which is present in plant cell walls. Ferulic acid is a phenolic acid that can be absorbed by the small intestine and excreted through the urine. It is one of the most abundant phenolic acids in plants, varying from 5 g/kg in wheat bran to 9 g/kg in sugar-beet pulp and 50 g/kg in corn kernel. It occurs primarily in seeds and leaves both in its free form (albeit rarely) and covalently linked to lignin and other biopolymers. It is usually found as ester cross-links with polysaccharides in the cell wall, such as arabinoxylans in grasses, pectin in spinach and sugar beet, and xyloglucans in bamboo. It also can cross-link with proteins. Due to its phenolic nucleus and an extended side chain conjugation (carbohydrates and proteins), it readily forms a resonance-stabilized phenoxy radical which accounts for its potent antioxidant potential. Food supplementation with curcumin and ferulic acid is considered a nutritional approach to reducing oxidative damage and amyloid pathology in Alzheimer disease (PMID:17127365, 1398220, 15453708, 9878519). Ferulic acid can be found in Pseudomonas and Saccharomyces (PMID:8395165).
1-[(5-Amino-5-carboxypentyl)amino]-1-deoxyfructose is found in milk and milk products. Amadori rearrangement produced found in heated milk and other foodstuff
1-[(5-Amino-5-carboxypentyl)amino]-1-deoxyfructose is found in milk and milk products. Amadori rearrangement produced found in heated milk and other foodstuff
Fumaric acid is a dicarboxylic acid. It is a precursor to L-malate in the Krebs tricarboxylic acid (TCA) cycle. It is formed by the oxidation of succinic acid by succinate dehydrogenase. Fumarate is converted by the enzyme fumarase to malate. Fumaric acid has recently been identified as an oncometabolite or an endogenous, cancer causing metabolite. High levels of this organic acid can be found in tumors or biofluids surrounding tumors. Its oncogenic action appears to due to its ability to inhibit prolyl hydroxylase-containing enzymes. In many tumours, oxygen availability becomes limited (hypoxia) very quickly due to rapid cell proliferation and limited blood vessel growth. The major regulator of the response to hypoxia is the HIF transcription factor (HIF-alpha). Under normal oxygen levels, protein levels of HIF-alpha are very low due to constant degradation, mediated by a series of post-translational modification events catalyzed by the prolyl hydroxylase domain-containing enzymes PHD1, 2 and 3, (also known as EglN2, 1 and 3) that hydroxylate HIF-alpha and lead to its degradation. All three of the PHD enzymes are inhibited by fumarate. Fumaric acid is found to be associated with fumarase deficiency, which is an inborn error of metabolism. It is also a metabolite of Aspergillus.
Gabapentin was originally developed as a chemical analogue of gamma-aminobutyric acid (GABA) to reduce the spinal reflex for the treatment of spasticity and was found to have anticonvulsant activity in various seizure models. In addition, it also displays antinociceptive activity in various animal pain models. Clinically, gabapentin is indicated as an add-on medication for the treatment of partial seizures, and neuropathic pain. It was also claimed to be beneficial in several other clinical disorders such as anxiety, bipolar disorder, and hot flashes. The possible mechanisms or targets involved in the multiple therapeutic actions of gabapentin have been actively studied. Since gabapentin was developed, several hypotheses had been proposed for its action mechanisms. They include selectively activating the heterodimeric GABA(B) receptors consisting of GABA(B1a) and GABA(B2) subunits, selectively enhancing the NMDA current at GABAergic interneurons, or blocking AMPA-receptor-mediated transmission in the spinal cord, binding to the L-alpha-amino acid transporter, activating ATP-sensitive K(+) channels, activating hyperpolarization-activated cation channels, and modulating Ca(2+) current by selectively binding to the specific binding site of [(3)H]gabapentin, the alpha(2)delta subunit of voltage-dependent Ca(2+) channels. Different mechanisms might be involved in different therapeutic actions of gabapentin. In this review, we summarized the recent progress in the findings proposed for the antinociceptive action mechanisms of gabapentin and suggest that the alpha(2)delta subunit of spinal N-type Ca(2+) channels is very likely the analgesic action target of gabapentin. (PMID: 16474201).
Galactinol belongs to the class of organic compounds known as O-glycosyl compounds. These are glycoside in which a sugar group is bonded through one carbon to another group via an O-glycosidic bond. Galactinol is an extremely weak basic (essentially neutral) compound (based on its pKa). Galactinol is an intermediate in galactose metabolism. Galactinol is the fourth-to-last step in the synthesis of D-galactose and the third-to-last step in the synthesis of D-glucose and D-fructose. Galactinol is converted from UDP-galactose via the enzyme inositol 3-alpha-galactosyltransferase (EC 2.4.1.123). It is then converted into raffinose via the enzyme raffinose synthase (EC 2.4.1.82).
Galactitol or dulcitol is a sugar alcohol that is a metabolic breakdown product of galactose. Galactose is derived from lactose in food (such as dairy products). When lactose is broken down by the enzyme lactase it produces glucose and galactose. Galactitol has a slightly sweet taste. It is produced from galactose in a reaction catalyzed by aldose reductase. When present in sufficiently high levels, galactitol can act as a metabotoxin, a neurotoxin, and a hepatotoxin. A neurotoxin is a compound that disrupts or attacks neural cells and neural tissue. A hepatotoxin as a compound that disrupts or attacks liver tissue or liver cells. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Chronically high levels of galactitol are associated with at least two inborn errors of metabolism, including galactosemia and galactosemia type II. Galactosemia is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly. Excess lactose consumption in individuals with galactose intolerance or galactosemia activates aldose reductase to produce galactitol, thus depleting NADPH and leading to lowered glutathione reductase activity. As a result, hydrogen peroxide or other free radicals accumulate causing serious oxidative damage to various cells and tissues. In individuals with galactosemia, the enzymes needed for the further metabolism of galactose (galactose-1-phosphate uridyltransferase) are severely diminished or missing entirely, leading to toxic levels of galactose 1-phosphate, galactitol, and galactonate. High levels of galactitol in infants are specifically associated with hepatomegaly (an enlarged liver), cirrhosis, renal failure, cataracts, vomiting, seizure, hypoglycemia, lethargy, brain damage, and ovarian failure.
Galactosylhydroxylysine is released during bone resorption and elevated in subjects with metabolic bone loss. Galactosylhydroxylysine is a sensitive and specific marker of bone resorption. (PMID 10222355).
Gamma glutamyl ornithine is found in human urine. - PubMed reference: 1148212. Gamma-glutamylornithine has been identified in urine from patients with the HHH syndrome (hyperornithinemia, hyperammonemia and homocitrullinuria) and with gyrate atrophy associated with hyperornithinemia. The amount of gamma-glutamylornithine excreted was 10-15 times higher than that excreted in normal subjects. - PubMed reference: 6547887.
N2-gamma-Glutamylglutamine, also known as gamma-L-Glu-L-Gln or L-gamma-glutamyl-L-glutamine, belongs to the class of organic compounds known as dipeptides. These are organic compounds containing a sequence of exactly two alpha-amino acids joined by a peptide bond. N2-gamma-Glutamylglutamine is a very strong basic compound (based on its pKa). N2-gamma-Glutamylglutamine is a dipeptide obtained from the condensation of the gamma-carboxy group of glutamic acid with the alpha-amino group of glutamine. Some dipeptides are known to have physiological or cell-signalling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
In non-diabetic kidney scarring the protein crosslinking enzyme tissue transglutaminase (tTg) has been implicated in the process by the formation of increased epsilon-(gamma-glutamyl)lysine bonds between ECM components in both experimental and human disease. Changes in tTg and epsilon-(gamma-glutamyl)lysine occur in human Diabetic nephropathy as well, the leading cause of chronic kidney failure. (PMID 15292688). In Parkinson's disease (PD), conformational changes in the alpha-synuclein monomer precede the formation of Lewy bodies. Both tTG and its substrate-characteristic N(epsilon)-(gamma-glutamyl)-lysine crosslink are increased in PD nigral dopamine neurons. (PMID 15001552). Expression of tissue transglutaminase (tTgase) and epsilon-(gamma-glutamyl)-lysine was present in all scarring of the blebs sites, being the main cause of failure in glaucoma filtration surgery. Transglutaminases are calcium-dependent enzymes that catalyze the posttranslational modification of proteins through an acyl transfer reaction between the gamma-carboxamide group of a peptide-bound glutaminyl residue and various amines. Covalent cross-linking using epsilon-(gamma-glutamyl)-lysine bonds is stable and resistant to enzymatic, chemical, and mechanical disruption. (PMID: 16936095).
In non-diabetic kidney scarring the protein crosslinking enzyme tissue transglutaminase (tTg) has been implicated in the process by the formation of increased epsilon-(gamma-glutamyl)lysine bonds between ECM components in both experimental and human disease. Changes in tTg and epsilon-(gamma-glutamyl)lysine occur in human Diabetic nephropathy as well, the leading cause of chronic kidney failure. (PMID 15292688). In Parkinson's disease (PD), conformational changes in the alpha-synuclein monomer precede the formation of Lewy bodies. Both tTG and its substrate-characteristic N(epsilon)-(gamma-glutamyl)-lysine crosslink are increased in PD nigral dopamine neurons. (PMID 15001552). Expression of tissue transglutaminase (tTgase) and epsilon-(gamma-glutamyl)-lysine was present in all scarring of the blebs sites, being the main cause of failure in glaucoma filtration surgery. Transglutaminases are calcium-dependent enzymes that catalyze the posttranslational modification of proteins through an acyl transfer reaction between the gamma-carboxamide group of a peptide-bound glutaminyl residue and various amines. Covalent cross-linking using epsilon-(gamma-glutamyl)-lysine bonds is stable and resistant to enzymatic, chemical, and mechanical disruption. (PMID: 16936095).
gamma-Glutamylthreonine is a dipeptide composed of gamma-glutamate and threonine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. gamma-Glutamylthreonine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
gamma-Glutamylthreonine is a dipeptide composed of gamma-glutamate and threonine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. gamma-Glutamylthreonine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
gamma-Glutamylthreonine is a dipeptide composed of gamma-glutamate and threonine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. gamma-Glutamylthreonine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
gamma-Glutamylthreonine is a dipeptide composed of gamma-glutamate and threonine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. gamma-Glutamylthreonine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis.
4-Guanidinobutanoic acid, also known as gamma-guanidinobutyrate or 4-(carbamimidamido)butanoate, belongs to the class of organic compounds known as gamma amino acids and derivatives. These are amino acids having a (-NH2) group attached to the gamma carbon atom. 4-Guanidinobutanoic acid is a normal metabolite present in low concentrations. 4-Guanidinobutanoic acid exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, 4-Guanidinobutanoic acid has been detected, but not quantified in a few different foods, such as apples, french plantains, and loquats. This could make 4-guanidinobutanoic acid a potential biomarker for the consumption of these foods. Patients with hyperargininemia have an arginase deficiency which leads to blockade of the urea cycle in the last step with several clinical symptoms. Owing to the arginase deficiency this patients accumulate arginine which leads eventually to epileptogenic guanidino compounds (PMID 7752905).
Glipizide is only found in individuals that have used or taken this drug. It is an oral hypoglycemic agent which is rapidly absorbed and completely metabolized. [PubChem]Sulfonylureas likely bind to ATP-sensitive potassium-channel receptors on the pancreatic cell surface, reducing potassium conductance and causing depolarization of the membrane. Depolarization stimulates calcium ion influx through voltage-sensitive calcium channels, raising intracellular concentrations of calcium ions, which induces the secretion, or exocytosis, of insulin.
Glucaric acid, also known as glucarate or D-saccharic acid, belongs to the class of organic compounds known as glucuronic acid derivatives. Glucuronic acid derivatives are compounds containing a glucuronic acid moiety (or a derivative), which consists of a glucose moiety with the C6 carbon oxidized to a carboxylic acid. Glucaric acid is a sugar acid derived from D-glucose in which both the aldehydic carbon atom and the carbon atom bearing the primary hydroxyl group are oxidized to carboxylic acid groups. D-glucaric acid is found in fruits, vegetables, and mammals. The highest concentrations of glucaric acid are found in grapefruits, apples, oranges, and cruciferous vegetables (PMID: 18772850). Glucaric acid is produced through the oxidation of glucose. Cytochrome P450 is thought to be responsible for the production of D-glucaric acid in vivo (PMID: 3779687). In mammals, D-glucaric acid and D-glucaro-l,4-lactone are also known end-products of the D-glucuronic acid pathway (PMID: 18772850). Glucaric is available as a dietary supplement in the form of calcium D-glucarate and has been studied for therapeutic purposes including cholesterol reduction and cancer chemotherapy (PMID: 9101079). D-Glucaric acid has a potential use as a building block for a number of polymers, including new nylons and hyperbranched polyesters. D-glucaric acid produced from D-glucose has been successfully utilized to produce a hydroxylated nylon.
Glucaric acid, also known as glucarate or D-saccharic acid, belongs to the class of organic compounds known as glucuronic acid derivatives. Glucuronic acid derivatives are compounds containing a glucuronic acid moiety (or a derivative), which consists of a glucose moiety with the C6 carbon oxidized to a carboxylic acid. Glucaric acid is a sugar acid derived from D-glucose in which both the aldehydic carbon atom and the carbon atom bearing the primary hydroxyl group are oxidized to carboxylic acid groups. D-glucaric acid is found in fruits, vegetables, and mammals. The highest concentrations of glucaric acid are found in grapefruits, apples, oranges, and cruciferous vegetables (PMID: 18772850). Glucaric acid is produced through the oxidation of glucose. Cytochrome P450 is thought to be responsible for the production of D-glucaric acid in vivo (PMID: 3779687). In mammals, D-glucaric acid and D-glucaro-l,4-lactone are also known end-products of the D-glucuronic acid pathway (PMID: 18772850). Glucaric is available as a dietary supplement in the form of calcium D-glucarate and has been studied for therapeutic purposes including cholesterol reduction and cancer chemotherapy (PMID: 9101079). D-Glucaric acid has a potential use as a building block for a number of polymers, including new nylons and hyperbranched polyesters. D-glucaric acid produced from D-glucose has been successfully utilized to produce a hydroxylated nylon.
alpha-D-Glucose, also known as alpha-dextrose or alpha-D-GLC, belongs to the class of organic compounds known as hexoses. These are monosaccharides in which the sugar unit is a is a six-carbon containing moeity. alpha-D-Glucose exists in all living species, ranging from bacteria to humans. Outside of the human body, alpha-D-Glucose has been detected, but not quantified in several different foods, such as lemon grass, sourdoughs, mixed nuts, sweet rowanberries, and ginsengs. This could make alpha-D-glucose a potential biomarker for the consumption of these foods. D-Glucopyranose having alpha-configuration at the anomeric centre.
Galactosylglycerol is an intermediate in galactose and glycerolipid metabolism (KEGG: C05401). In galactose metabolism, galactosylglycerol is reversibly produced from D-galactose and glycerol by the enzyme alpha-galactosidase [EC:3.2.1.22]. It is also the first to last step in the synthesis of glycerol and is converted from 1,2-diacyl-3-beta-D-galactosyl-sn-glycerol. It is then converted to glycerol via the enzyme beta-galactosidase [EC:3.2.1.23].
Glucosylgalactosyl hydroxylysine is a Glycoside of hydroxylysine. Hydroxylation of lysine is an important post-translational modification of collagen, (PMID 10928217) a reaction catalyzed by the enzyme Lysyl hydroxylase (EC 1.14.11.4) forming hydroxylysine in collagens and other proteins with collagen-like amino acid sequences, by the hydroxylation of lysine residues in X-lys-gly sequences. The hydroxylysine residues formed in the lysyl hydroxylase reaction have 2 important functions: first, their hydroxy groups serve as sites of attachment for carbohydrate units, either the monosaccharide galactose or the disaccharide glucosylgalactose; and second, they are essential for the stability of the intermolecular collagen crosslinks. (OMIM 153454). Hydroxylysine-deficient skin collagen is manifested in Ehlers-Danlos syndrome, type VIA, A heritable disorder of connective tissue (PMID 5016372).
D-Glutamine, also known as DGN or D glutamine, belongs to the class of organic compounds known as d-alpha-amino acids. These are alpha amino acids which have the D-configuration of the alpha-carbon atom. Supplementation does not appear to be useful in adults or children with Crohn's disease or inflammatory bowel disease, but clinical studies as of 2016 were underpowered. D-Glutamine is a drug. D-Glutamine exists in all living species, ranging from bacteria to humans. D-Glutamine is a potentially toxic compound. Adverse effects of glutamine have been described for people receiving home parenteral nutrition and those with liver-function abnormalities. Glutamine is the most abundant naturally occurring, nonessential amino acid in the human body, and one of the few amino acids that can directly cross the blood-brain barrier. Glutamine can exist in either of two enantiomeric forms, L-glutamine and D-glutamine.
Glycyl-Lysine is a dipeptide composed of glycine and lysine. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
2-Phosphoglyceric acid (2PGA) is a glyceric acid which serves as the substrate in the ninth step of glycolysis. It is catalyzed by enolase into phosphoenolpyruvate (PEP), the penultimate step in the conversion of glucose to pyruvate. Enolase catalyzes the beta-elimination reaction in a stepwise manner wherein OH- is eliminated from C3 of a discrete carbanion (enolate) intermediate. This intermediate is created by removal of the proton from C2 of 2PGA by a base in the active site (PMID: 8994873, Wikipedia).
Glyceric acid is a colourless syrupy acid, obtained from oxidation of glycerol. It is a compound that is secreted excessively in the urine by patients suffering from D-glyceric aciduria, an inborn error of metabolism, and D-glycerate anemia. Deficiency of human glycerate kinase leads to D-glycerate acidemia/D-glyceric aciduria. Symptoms of the disease include progressive neurological impairment, hypotonia, seizures, failure to thrive, and metabolic acidosis. At sufficiently high levels, glyceric acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Glyceric acid is an organic acid. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, seizures, coma, and possibly death. These are also the characteristic symptoms of untreated glyceric aciduria. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures. Elevated values may also be due to microbial sources such as yeast (Aspergillus, Penicillium, probably Candida) or due to dietary sources containing glycerol (glycerine). Glyceric acid is isolated from various plants (e.g. brassicas, pulses, and Vicia faba).
Glyceric acid is a colourless syrupy acid, obtained from oxidation of glycerol. It is a compound that is secreted excessively in the urine by patients suffering from D-glyceric aciduria, an inborn error of metabolism, and D-glycerate anemia. Deficiency of human glycerate kinase leads to D-glycerate acidemia/D-glyceric aciduria. Symptoms of the disease include progressive neurological impairment, hypotonia, seizures, failure to thrive, and metabolic acidosis. At sufficiently high levels, glyceric acid can act as an acidogen and a metabotoxin. An acidogen is an acidic compound that induces acidosis, which has multiple adverse effects on many organ systems. A metabotoxin is an endogenously produced metabolite that causes adverse health effects at chronically high levels. Glyceric acid is an organic acid. Abnormally high levels of organic acids in the blood (organic acidemia), urine (organic aciduria), the brain, and other tissues lead to general metabolic acidosis. Acidosis typically occurs when arterial pH falls below 7.35. In infants with acidosis, the initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These can progress to heart abnormalities, seizures, coma, and possibly death. These are also the characteristic symptoms of untreated glyceric aciduria. Many affected children with organic acidemias experience intellectual disability or delayed development. In adults, acidosis or acidemia is characterized by headaches, confusion, feeling tired, tremors, sleepiness, and seizures. Elevated values may also be due to microbial sources such as yeast (Aspergillus, Penicillium, probably Candida) or due to dietary sources containing glycerol (glycerine). Glyceric acid is isolated from various plants (e.g. brassicas, pulses, and Vicia faba).
Glycerophosphorylcholine (GPC) is a choline derivative and one of the two major forms of choline storage (along with phosphocholine) in the cytosol. Glycerophosphorylcholine is also one of the four major organic osmolytes in renal medullary cells, changing their intracellular osmolyte concentration in parallel with extracellular tonicity during cellular osmoadaptation. As an osmolyte, Glycerophosphorylcholine counteracts the effects of urea on enzymes and other macromolecules. Kidneys (especially medullar cells), which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, GPC), decreased degradation (GPC) and reduced osmolyte release. GPC is formed in the breakdown of phosphatidylcholine (PtC). This pathway is active in many body tissues, including mammary tissue.
Glycerophosphorylcholine (GPC) is a choline derivative and one of the two major forms of choline storage (along with phosphocholine) in the cytosol. Glycerophosphorylcholine is also one of the four major organic osmolytes in renal medullary cells, changing their intracellular osmolyte concentration in parallel with extracellular tonicity during cellular osmoadaptation. As an osmolyte, Glycerophosphorylcholine counteracts the effects of urea on enzymes and other macromolecules. Kidneys (especially medullar cells), which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, GPC), decreased degradation (GPC) and reduced osmolyte release. GPC is formed in the breakdown of phosphatidylcholine (PtC). This pathway is active in many body tissues, including mammary tissue.
Glycerophosphorylcholine (GPC) is a choline derivative and one of the two major forms of choline storage (along with phosphocholine) in the cytosol. Glycerophosphorylcholine is also one of the four major organic osmolytes in renal medullary cells, changing their intracellular osmolyte concentration in parallel with extracellular tonicity during cellular osmoadaptation. As an osmolyte, Glycerophosphorylcholine counteracts the effects of urea on enzymes and other macromolecules. Kidneys (especially medullar cells), which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, GPC), decreased degradation (GPC) and reduced osmolyte release. GPC is formed in the breakdown of phosphatidylcholine (PtC). This pathway is active in many body tissues, including mammary tissue.
Glycochenodeoxycholate-3-sulfate is a bile salt formed in the liver from chenodeoxycholate and glycine, usually as the sodium salt. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is a cholagogue and choleretic.
Glycochenodeoxycholic acid (GCDC)induced the mitochondrial permeability transition (MPT) in a dose-dependent manner, which was inhibited by cyclosporin A, alpha-tocopherol, beta-carotene and idebenone. GCDC stimulated reactive oxygen species generation and release of cytochrome c and apoptosis-inducing factor, which were significantly inhibited by the antioxidants, cyclosporin A, and tauroursodeoxycholic acid. mitochondrial pathways of cell death are stimulated in human hepatic mitochondria exposed to GCDC consistent with the role of mitochondrial dysfunction in the pathogenesis of cholestatic liver injury. (16056106).
Guaiacol is a phenolic compound with a methoxy group and is the monomethyl ether of catechol. Guaiacol is readily oxidized by the heme iron of peroxidases including the peroxidase of cyclooxygenase (COX) enzymes. It therefore serves as a reducing co-substrate for COX reactions. Guaiacol is a phenolic natural product first isolated from Guaiac resin and the oxidation of lignin. It is a yellowish aromatic oil that is now commonly derived from guaiacum or wood creosote. It is used medicinally as an expectorant, antiseptic, and local anesthetic. Guaiacol is used in traditional dental pulp sedation, and has the property of inducing cell proliferation; guaiacol is a potent scavenger of reactive oxygen radicals and its radical scavenging activity may be associated with its effect on cell proliferation. Guaiacol is also used in the preparation of synthetic vanillin. Guaiacol is also present in wood smoke, as a product of pyrolysis of lignin. Guaiacol has been found in the urine of patients with neuroblastoma and pheochromocytoma. (PMID 4344880, 16152729).
Guanidoacetic acid (GAA), also known as guanidinoacetate or glycocyamine, belongs to the class of organic compounds known as alpha amino acids and derivatives. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon), or a derivative thereof. Guanidinoacetic acid was first prepared in 1861 by Adolph Strecker by reaction of cyanamide with glycine in aqueous solution. Manufactured guanidinoacetic acid is primarily used a feed additive approved by EFSA in poultry farming (for fattening), and pigs for fattening. Guanidoacetic acid exists naturally in all vertebrates. It is formed primarily in the kidneys by transferring the guanidine group of L-arginine to the amino acid glycine via the enzyme known as L-Arg:Gly-amidinotransferase (AGAT). In a further step, guanidinoacetate is methylated to generate creatine using S-adenosyl methionine (as the methyl donor) via the enzyme known as guanidinoacetate N-methyltransferase (GAMT). The resulting creatine is released into the bloodstream. Elevated levels of guanidoacetic acid are a characteristic of an inborn metabolic disorder known as Guanidinoacetate Methyltransferase (GAMT) Deficiency. GAMT converts guanidinoacetate to creatine and deficiency of this enzyme results in creatine depletion and accumulation of guanidinoacetate The disorder is transmitted in an autosomal recessive fashion and is localized to mutations on chromosome 19p13.3. GAMT deficiency is characterized by developmental arrest, medication-resistant epilepsy (myoclonic, generalized tonic-clonic, partial complex, atonic), severe speech impairment, progressive dystonia, dyskinesias, hypotonia, ataxia, and autistic-like behavior.
Hexanoylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycineHexanoylglycine is a fatty acid metabolite, it appears in the urine of patients with hereditary medium-chain acyl-CoA dehydrogenase (MCAD) deficiency (PMID 2775902), which is a genetic disorder.
D-Galactose (CAS: 59-23-4) is an aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. D-Galactose is an energy-providing nutrient and also a necessary basic substrate for the biosynthesis of many macromolecules in the body. Metabolic pathways for D-galactose are important not only for the provision of these pathways but also for the prevention of D-galactose metabolite accumulation. The main source of D-galactose is lactose in the milk of mammals, but it can also be found in some fruits and vegetables. Utilization of D-galactose in all living cells is initiated by the phosphorylation of the hexose by the enzyme galactokinase (E.C. 2.7.1.6) (GALK) to form D-galactose-1-phosphate. In the presence of D-galactose-1-phosphate uridyltransferase (E.C. 2.7.7.12) (GALT) D-galactose-1-phosphate is exchanged with glucose-1-phosphate in UDP-glucose to form UDP-galactose. Glucose-1-phosphate will then enter the glycolytic pathway for energy production. Deficiency of the enzyme GALT in galactosemic patients leads to the accumulation of D-galactose-1-phosphate. Classic galactosemia, a term that denotes the presence of D-galactose in the blood, is the rare inborn error of D-galactose metabolism, diagnosed by the deficiency of the second enzyme of the D-galactose assimilation pathway, GALT, which, in turn, is caused by mutations at the GALT gene (PMID: 15256214, 11020650, 10408771). Galactose in the urine is a biomarker for the consumption of milk.
D-Galactose (CAS: 59-23-4) is an aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. D-Galactose is an energy-providing nutrient and also a necessary basic substrate for the biosynthesis of many macromolecules in the body. Metabolic pathways for D-galactose are important not only for the provision of these pathways but also for the prevention of D-galactose metabolite accumulation. The main source of D-galactose is lactose in the milk of mammals, but it can also be found in some fruits and vegetables. Utilization of D-galactose in all living cells is initiated by the phosphorylation of the hexose by the enzyme galactokinase (E.C. 2.7.1.6) (GALK) to form D-galactose-1-phosphate. In the presence of D-galactose-1-phosphate uridyltransferase (E.C. 2.7.7.12) (GALT) D-galactose-1-phosphate is exchanged with glucose-1-phosphate in UDP-glucose to form UDP-galactose. Glucose-1-phosphate will then enter the glycolytic pathway for energy production. Deficiency of the enzyme GALT in galactosemic patients leads to the accumulation of D-galactose-1-phosphate. Classic galactosemia, a term that denotes the presence of D-galactose in the blood, is the rare inborn error of D-galactose metabolism, diagnosed by the deficiency of the second enzyme of the D-galactose assimilation pathway, GALT, which, in turn, is caused by mutations at the GALT gene (PMID: 15256214, 11020650, 10408771). Galactose in the urine is a biomarker for the consumption of milk.
D-Galactose (CAS: 59-23-4) is an aldohexose that occurs naturally in the D-form in lactose, cerebrosides, gangliosides, and mucoproteins. D-Galactose is an energy-providing nutrient and also a necessary basic substrate for the biosynthesis of many macromolecules in the body. Metabolic pathways for D-galactose are important not only for the provision of these pathways but also for the prevention of D-galactose metabolite accumulation. The main source of D-galactose is lactose in the milk of mammals, but it can also be found in some fruits and vegetables. Utilization of D-galactose in all living cells is initiated by the phosphorylation of the hexose by the enzyme galactokinase (E.C. 2.7.1.6) (GALK) to form D-galactose-1-phosphate. In the presence of D-galactose-1-phosphate uridyltransferase (E.C. 2.7.7.12) (GALT) D-galactose-1-phosphate is exchanged with glucose-1-phosphate in UDP-glucose to form UDP-galactose. Glucose-1-phosphate will then enter the glycolytic pathway for energy production. Deficiency of the enzyme GALT in galactosemic patients leads to the accumulation of D-galactose-1-phosphate. Classic galactosemia, a term that denotes the presence of D-galactose in the blood, is the rare inborn error of D-galactose metabolism, diagnosed by the deficiency of the second enzyme of the D-galactose assimilation pathway, GALT, which, in turn, is caused by mutations at the GALT gene (PMID: 15256214, 11020650, 10408771). Galactose in the urine is a biomarker for the consumption of milk.
Hippuric acid is an acyl glycine formed from the conjugation of benzoic acid with glycine. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. Hippuric acid is a normal component of urine and is typically increased with increased consumption of phenolic compounds (tea, wine, fruit juices). These phenols are converted into benzoic acid which is then converted into hippuric acid and excreted in the urine. Hippuric acid is the most frequently used biomarker in the biological monitoring of occupational exposure to toluene. This product of solvent biotransformation may be also found in the urine of individuals who have not been exposed to the solvent. A smaller fraction of the absorbed toluene is oxidized into aromatic compounds including ortho-cresol, which is not found in the urine of nonexposed individuals in a significant amount. The concentration of hippuric acid in the urine of individuals exposed to a low toluene concentration does not differ from that of individuals not exposed to the solvent. This has led to the conclusion that hippuric acid should not be utilized in the biological monitoring of occupational exposure to low levels of toluene in the air. Protein-bound organic acids such as hippuric acid are markedly accumulated in uremic plasma and produce defective protein binding of drugs (PMID: 9120876 , 8734460). Hippuric acid has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Hippuric acid is also found to be associated with phenylketonuria, propionic acidemia, and tyrosinemia I, which are inborn errors of metabolism. Hippuric acid is an endogenous phenolic acid metabolite detected after the consumption of whole grain.
Histamine is an amine derived by enzymatic decarboxylation of histidine. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter. Histamine can be found in Photobacterium phosphoreum and Lactobacillus (PMID:17066936). Histamine belongs to the class of organic compounds known as 2-arylethylamines. These are primary amines that have the general formula RCCNH2, where R is an organic group. High amounts of histamine have been found in spinach, oats and ryes. Another foods such as green beans, broccoli, and beetroots also contain histamine but in lower concentrations. Histamine has also been detected but not quantified in several different foods, such as groundcherries, carobs, bok choy, biscuits, and longans.
L-homoarginine, also known as N6-(aminoiminomethyl)-L-lysine or N6-amidino-L-lysine, is a member of the class of compounds known as L-alpha-amino acids. L-alpha-amino acids are alpha amino acids which have the L-configuration of the alpha-carbon atom. More specifically, L-homoarginine is a naturally occurring, non-proteinogenic, cationic amino acid. It is formed in the liver in a reaction catalyzed by L-arginine:glycine amidinotransferase (AGAT) when transferring the amidino group from arginine to lysine. It is an alternative substrate for nitric oxide (NO) synthase. L-homoarginine increases the availability of NO and thereby affects endothelial function. High homoarginine levels may exert positive actions that are relevant to cardiovascular health, including enhanced endothelial function, inhibition of platelet aggregation and stimulation of insulin secretion (PMID: 30866658). Recent studies have demonstrated that low serum homoarginine levels are a strong predictor of cardiovascular mortality (PMID: 24583919). L-homoarginine is a substrate of the human cationic amino acid CAT1 [solute carrier family 7 (SLC7A1)], CAT2A (SLC7A2A) or CAT2B (SLC7A2B) (PMID: 28684763). According to published human metabolomic data, L-homoarginine can be found primarily in blood, cerebrospinal fluid (CSF), and urine, as well as in human intestinal and testes tissues. Moreover, L-homoarginine has been found to be associated with liver cirrhosis and the genetic disorder, hyperargininemia. Homoarginine is an organ-specific uncompetitive inhibitor of human liver and bone alkaline phosphohydrolase (PMID: 5063678).
L-homoarginine, also known as N6-(aminoiminomethyl)-L-lysine or N6-amidino-L-lysine, is a member of the class of compounds known as L-alpha-amino acids. L-alpha-amino acids are alpha amino acids which have the L-configuration of the alpha-carbon atom. More specifically, L-homoarginine is a naturally occurring, non-proteinogenic, cationic amino acid. It is formed in the liver in a reaction catalyzed by L-arginine:glycine amidinotransferase (AGAT) when transferring the amidino group from arginine to lysine. It is an alternative substrate for nitric oxide (NO) synthase. L-homoarginine increases the availability of NO and thereby affects endothelial function. High homoarginine levels may exert positive actions that are relevant to cardiovascular health, including enhanced endothelial function, inhibition of platelet aggregation and stimulation of insulin secretion (PMID: 30866658). Recent studies have demonstrated that low serum homoarginine levels are a strong predictor of cardiovascular mortality (PMID: 24583919). L-homoarginine is a substrate of the human cationic amino acid CAT1 [solute carrier family 7 (SLC7A1)], CAT2A (SLC7A2A) or CAT2B (SLC7A2B) (PMID: 28684763). According to published human metabolomic data, L-homoarginine can be found primarily in blood, cerebrospinal fluid (CSF), and urine, as well as in human intestinal and testes tissues. Moreover, L-homoarginine has been found to be associated with liver cirrhosis and the genetic disorder, hyperargininemia. Homoarginine is an organ-specific uncompetitive inhibitor of human liver and bone alkaline phosphohydrolase (PMID: 5063678).
Homocysteinesulfinic acid, is involved in many metabolic pathways including trans-sulfuration in cysteine synthesis, re-methylation in methionine synthesis,. trans-methylation of DNA, proteins, and lipids, and biosynthesis of small hormonal and neuronal signaling molecules.
Homoserine is a more reactive variant of the amino acid serine. In this variant, the hydroxyl side chain contains an additional CH2 group which brings the hydroxyl group closer to its own carboxyl group, allowing it to chemically react to form a five-membered ring. This occurs at the point that amino acids normally join to their neighbours in a peptide bond. Homoserine is therefore unsuitable for forming proteins and has been eliminated from the repertoire of amino acids used by living things. Homoserine is the final product on the C-terminal end of the N-terminal fragment following a cyanogen bromide cleavage. (wikipedia). Homoserine is also a microbial metabolite.
Homoserine is a more reactive variant of the amino acid serine. In this variant, the hydroxyl side chain contains an additional CH2 group which brings the hydroxyl group closer to its own carboxyl group, allowing it to chemically react to form a five-membered ring. This occurs at the point that amino acids normally join to their neighbours in a peptide bond. Homoserine is therefore unsuitable for forming proteins and has been eliminated from the repertoire of amino acids used by living things. Homoserine is the final product on the C-terminal end of the N-terminal fragment following a cyanogen bromide cleavage. (wikipedia). Homoserine is also a microbial metabolite.
(S)-Homostachydrine (also known as pipecolic acid betaine or homostachydrine) can be found in green coffee beans of Robusta and Arabica species (PMID: 27006213). (S)-Homostachydrine content is unaffected by coffee bean roasting treatment because of its remarkable heat stability. This makes it a good candidate marker for determining the content of Robusta and Arabica species in roasted coffee blends. (S)-Homostachydrine is also a potential marker of coffee consumption as it can be found in both human serum and human urine. It is also found in alfalfa seeds and leaves. More specifically, (S)-homostachydrine can be isolated from the seeds of Medicago sativa (alfalfa) as well as from Achillea millefolium (yarrow). (S)-Homostachydrine is also found in the fruits, seeds, and leaves of orange, lemon, and bergamot (PMID: 22208890).
(S)-Homostachydrine (also known as pipecolic acid betaine or homostachydrine) can be found in green coffee beans of Robusta and Arabica species (PMID: 27006213). (S)-Homostachydrine content is unaffected by coffee bean roasting treatment because of its remarkable heat stability. This makes it a good candidate marker for determining the content of Robusta and Arabica species in roasted coffee blends. (S)-Homostachydrine is also a potential marker of coffee consumption as it can be found in both human serum and human urine. It is also found in alfalfa seeds and leaves. More specifically, (S)-homostachydrine can be isolated from the seeds of Medicago sativa (alfalfa) as well as from Achillea millefolium (yarrow). (S)-Homostachydrine is also found in the fruits, seeds, and leaves of orange, lemon, and bergamot (PMID: 22208890).
Hydantoin-5-propionic acid is a metabolite of histidine, urinary hydantoin-5-propionic acid occur in patients with disorders of folate/ vitamin B12 metabolism (PMID: 3760095). Folic acid non-dependent excessive formiminoglutamic aciduria (Figlu-uria) is an extremely rare disorder; treatment with oral folate supplements (15 mg/day) for 3 weeks failed to reduce urinary hydantoin-5-propionic acid (PMID: 8487495).
4-Hydroxy tolbutamide is a hydroxylation byproduct of tolbutamide. Tolbutamide is a first generation potassium channel blocker. It is a sulfonylurea oral hypoglycemic drug sold under the brand name Orinase. This drug may be used in the management of type II diabetes if diet alone is not effective. Tolbutamide stimulates the secretion of insulin by the pancreas.
Salicyluric acid is an aryl glycine conjugate formed by the body to eliminate excess salicylates, including aspirin. Aspirin is rapidly hydrolysed to salicylic acid which is further metabolized to various compounds, including salicyluric acid (SU) as well as various acyl and phenolic glucuronides, and hydroxylated metabolites. SU is the major metabolite of SA excreted in urine and it is present in the urine of people who have not taken salicylate drugs, although it has no anti-inflammatory effects in humans or in animals. More salicyluric acid (SU) is excreted in the urine of vegetarians than in non-vegetarians, primarily because fruits and vegetables are important sources of dietary salicylates. However, significantly less (10-15X) SU is excreted by vegetarians than individuals taking low-dose aspirin (PMID: 12944546). The induction of the salicyluric acid formation is one of the saturable pathways of salicylate elimination. The formation of the methyl ester of salicyluric acid is observed during the quantitation of salicyluric acid and other salicylate metabolites in urine by high-pressure liquid chromatography. This methyl ester formation causes artificially low values for salicyluric acid and high values for salicylic acid. (PMID: 6101164, 6857178). Salicyluric acid has been found to be a microbial metabolite.
Salicyluric acid is an aryl glycine conjugate formed by the body to eliminate excess salicylates, including aspirin. Aspirin is rapidly hydrolysed to salicylic acid which is further metabolized to various compounds, including salicyluric acid (SU) as well as various acyl and phenolic glucuronides, and hydroxylated metabolites. SU is the major metabolite of SA excreted in urine and it is present in the urine of people who have not taken salicylate drugs, although it has no anti-inflammatory effects in humans or in animals. More salicyluric acid (SU) is excreted in the urine of vegetarians than in non-vegetarians, primarily because fruits and vegetables are important sources of dietary salicylates. However, significantly less (10-15X) SU is excreted by vegetarians than individuals taking low-dose aspirin (PMID: 12944546). The induction of the salicyluric acid formation is one of the saturable pathways of salicylate elimination. The formation of the methyl ester of salicyluric acid is observed during the quantitation of salicyluric acid and other salicylate metabolites in urine by high-pressure liquid chromatography. This methyl ester formation causes artificially low values for salicyluric acid and high values for salicylic acid. (PMID: 6101164, 6857178). Salicyluric acid has been found to be a microbial metabolite.
Salicyluric acid is an aryl glycine conjugate formed by the body to eliminate excess salicylates, including aspirin. Aspirin is rapidly hydrolysed to salicylic acid which is further metabolized to various compounds, including salicyluric acid (SU) as well as various acyl and phenolic glucuronides, and hydroxylated metabolites. SU is the major metabolite of SA excreted in urine and it is present in the urine of people who have not taken salicylate drugs, although it has no anti-inflammatory effects in humans or in animals. More salicyluric acid (SU) is excreted in the urine of vegetarians than in non-vegetarians, primarily because fruits and vegetables are important sources of dietary salicylates. However, significantly less (10-15X) SU is excreted by vegetarians than individuals taking low-dose aspirin (PMID: 12944546). The induction of the salicyluric acid formation is one of the saturable pathways of salicylate elimination. The formation of the methyl ester of salicyluric acid is observed during the quantitation of salicyluric acid and other salicylate metabolites in urine by high-pressure liquid chromatography. This methyl ester formation causes artificially low values for salicyluric acid and high values for salicylic acid. (PMID: 6101164, 6857178). Salicyluric acid has been found to be a microbial metabolite.
Hydroxyphenyllactic acid or 4-hydroxyphenyllactate (the L-form) is a tyrosine metabolite. The level of L-hydroxyphenyllactic acid is elevated in patients with a deficiency of the enzyme p-hydroxyphenylpyruvate oxidase (EC 1.14.2.2) (PMID: 4720815). L-hydroxyphenyllactate is present in relatively higher concentrations in the cerebrospinal fluid and urine of patients with phenylketonuria (PKU) and tyrosinemia (PMID: 3126358). However, the D-form of hydroxyphenyllactate is of bacterial origin and is also found in individuals with bacterial overgrowth or unusual gut microflora (PMID: 3126358).  Microbial hydroxyphenyllactate is likely derived from phenolic or polyphenolic compounds in the diet.  Bifidobacteria and lactobacilli produce considerable amounts of phenyllactic and p-hydroxyphenyllactic acids (PMID: 23061754).  It has also been shown that hydroxyphenyllactate decreases ROS (reactive oxygen species) production in both mitochondria and neutrophils and so hydroxyphenyllactate may function as a natural anti-oxidant (PMID: 23061754). Hydroxyphenyllactic acid is a microbial metabolite found in Acinetobacter, Bacteroides, Bifidobacteria, Bifidobacterium, Clostridium, Enterococcus, Escherichia, Eubacterium, Klebsiella, Lactobacillus, Pseudomonas and Staphylococcus (PMID: 19961416).
Hydroxyphenyllactic acid or 4-hydroxyphenyllactate (the L-form) is a tyrosine metabolite. The level of L-hydroxyphenyllactic acid is elevated in patients with a deficiency of the enzyme p-hydroxyphenylpyruvate oxidase (EC 1.14.2.2) (PMID: 4720815). L-hydroxyphenyllactate is present in relatively higher concentrations in the cerebrospinal fluid and urine of patients with phenylketonuria (PKU) and tyrosinemia (PMID: 3126358). However, the D-form of hydroxyphenyllactate is of bacterial origin and is also found in individuals with bacterial overgrowth or unusual gut microflora (PMID: 3126358).  Microbial hydroxyphenyllactate is likely derived from phenolic or polyphenolic compounds in the diet.  Bifidobacteria and lactobacilli produce considerable amounts of phenyllactic and p-hydroxyphenyllactic acids (PMID: 23061754).  It has also been shown that hydroxyphenyllactate decreases ROS (reactive oxygen species) production in both mitochondria and neutrophils and so hydroxyphenyllactate may function as a natural anti-oxidant (PMID: 23061754). Hydroxyphenyllactic acid is a microbial metabolite found in Acinetobacter, Bacteroides, Bifidobacteria, Bifidobacterium, Clostridium, Enterococcus, Escherichia, Eubacterium, Klebsiella, Lactobacillus, Pseudomonas and Staphylococcus (PMID: 19961416).
Imidazolelactic acid is the component of normal human urine. (PMID: 5856262). histidine loading causes an increase in the excretion of imidazolelactic acid. (PMID: 6021220). During pregnancy the values for imidazolelactic acid in urine is increased 3-fold. An interaction of allergic reactions and anomalies in the metabolism of the sex hormones are considered to form the basis of the pregnancy-specific illnesses that were studied. (PMID: 5789877). Urinary excretion of imidazolelactic acid is also an indication for folic acid and vitamin B12 deficiency. (PMID: 4645251).
Imidazolelactic acid is the component of normal human urine. (PMID: 5856262). histidine loading causes an increase in the excretion of imidazolelactic acid. (PMID: 6021220). During pregnancy the values for imidazolelactic acid in urine is increased 3-fold. An interaction of allergic reactions and anomalies in the metabolism of the sex hormones are considered to form the basis of the pregnancy-specific illnesses that were studied. (PMID: 5789877). Urinary excretion of imidazolelactic acid is also an indication for folic acid and vitamin B12 deficiency. (PMID: 4645251).
Iminodiacetic acid (IDA) is a dicarboxylic acid amine. It is a strongly acidic compound that is very water soluble. It naturally exists as a white powder. IDA is food by-product or intermediate produced via the reaction of glycine with acrylamide through the heating, baking or frying of carbohydrate-rich foods such as potatoes (PMID: 25212154).  Acrylamide is typically produced through a Maillard reaction (a heating reaction) of asparagine and various reducing sugars in plant-derived foods (PMID: 12368844). Concentrations of IDA are reduced in the plasma of individuals with autism (PMID: 33087514) and elevated in individuals with acute respiratory distress syndrome (ARDS) (PMID: 30779905). In addition to its role in metabolism, IDA has many industrial applications or roles. For instance, it is an important intermediate in the manufacture the herbicide glyphosate. IDA is also used in capillary electrophoresis for modulating peptide mobility and can be used as a precursor for the manufacture of the indicator xylenol orange. The iminodiacetate anion can act as a tridentate ligand to form a metal complex with two, fused, five membered chelate rings. The proton on the nitrogen atom can be replaced by a carbon atom of a polymer to create an ion-exchange resin, such as chelex 100. Iminodiacetic acid is used in HIDA (hepatobiliary iminodiacetic acid) scans or cholescintigraphy scans, that employ the radionuclide Technetium 99m, to diagnose several diseases in the liver, gallbladder and bile duct.
Iminodiacetic acid (IDA) is a dicarboxylic acid amine. It is a strongly acidic compound that is very water soluble. It naturally exists as a white powder. IDA is food by-product or intermediate produced via the reaction of glycine with acrylamide through the heating, baking or frying of carbohydrate-rich foods such as potatoes (PMID: 25212154).  Acrylamide is typically produced through a Maillard reaction (a heating reaction) of asparagine and various reducing sugars in plant-derived foods (PMID: 12368844). Concentrations of IDA are reduced in the plasma of individuals with autism (PMID: 33087514) and elevated in individuals with acute respiratory distress syndrome (ARDS) (PMID: 30779905). In addition to its role in metabolism, IDA has many industrial applications or roles. For instance, it is an important intermediate in the manufacture the herbicide glyphosate. IDA is also used in capillary electrophoresis for modulating peptide mobility and can be used as a precursor for the manufacture of the indicator xylenol orange. The iminodiacetate anion can act as a tridentate ligand to form a metal complex with two, fused, five membered chelate rings. The proton on the nitrogen atom can be replaced by a carbon atom of a polymer to create an ion-exchange resin, such as chelex 100. Iminodiacetic acid is used in HIDA (hepatobiliary iminodiacetic acid) scans or cholescintigraphy scans, that employ the radionuclide Technetium 99m, to diagnose several diseases in the liver, gallbladder and bile duct.
Indole is an aromatic heterocyclic organic compound. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing pyrrole ring. The participation of the nitrogen lone electron pair in the aromatic ring means that indole is not a base, and it does not behave like a simple amine. Indole is a microbial metabolite and it can be produced by bacteria as a degradation product of the amino acid tryptophan. It occurs naturally in human feces and has an intense fecal smell. At very low concentrations, however, indole has a flowery smell and is a constituent of many flower scents (such as orange blossoms) and perfumes. As a volatile organic compound, indole has been identified as a fecal biomarker of Clostridium difficile infection (PMID: 30986230). Natural jasmine oil, used in the perfume industry, contains around 2.5% of indole. Indole also occurs in coal tar. Indole has been found to be produced in a number of bacterial genera including Alcaligenes, Aspergillus, Escherichia, and Pseudomonas (PMID: 23194589, 2310183, 9680309). Indole plays a role in bacterial biofilm formation, bacterial motility, bacterial virulence, plasmid stability, and antibiotic resistance. It also functions as an intercellular signalling molecule (PMID: 26115989). Recently, it was determined that the bacterial membrane-bound histidine sensor kinase (HK) known as CpxA acts as a bacterial indole sensor to facilitate signalling (PMID: 31164470). It has been found that decreased indole concentrations in the gut promote bacterial pathogenesis, while increased levels of indole in the gut decrease bacterial virulence gene expression (PMID: 31164470). As a result, enteric pathogens sense a gradient of indole concentrations in the gut to migrate to different niches and successfully establish an infection.
2-Indolecarboxylic acid is a strong inhibitor of lipid peroxidation, similar to melatonin and some structurally related indole compounds. Lipid peroxidation with tert-butyl hydroperoxide is a source of free radicals (PMID 12236544). 2-Indolecarboxylic acid is a phenolic components known to exist in Korean ginseng (Koryo Insam Hakhoechi (1996), 20(3), 284-290) and brown rice (Han'guk Nonghwa Hakhoechi (1995), 38(5), 478-83).
Indoleacetic acid (IAA) is a breakdown product of tryptophan metabolism and is often produced by the action of bacteria in the mammalian gut. Higher levels of IAA are associated with bacteria from Clostridium species including C. stricklandii, C. lituseburense, C. subterminale, and C. putrefaciens (PMID: 12173102). IAA can be found in Agrobacterium, Azospirillum, Bacillus, Bradyrhizobium, Clostridium, Enterobacter, Pantoea, Pseudomonas, Rhizobium (PMID: 12173102, PMID: 17555270, PMID: 12147474, PMID: 19400643, PMID: 9450337, PMID: 21397014) (https://link.springer.com/chapter/10.1007/978-1-4612-3084-7_7) (https://escholarship.org/uc/item/1bf1b5m3). Some endogenous production of IAA in mammalian tissues also occurs. It may be produced by the decarboxylation of tryptamine or the oxidative deamination of tryptophan. IAA frequently occurs at low levels in urine and has been found in elevated levels in the urine of patients with phenylketonuria (PMID: 13610897). IAA has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Using material extracted from human urine, it was discovered by Kogl in 1933 that indoleacetic acid is also an important plant hormone (PMID: 13610897). Specifically, IAA is a member of the group of phytohormones called auxins. IAA is generally considered to be the most important native auxin. Plant cells synthesize IAA from tryptophan (Wikipedia). IAA and some derivatives can be oxidized by horseradish peroxidase (HRP) into cytotoxic species. IAA is only toxic after oxidative decarboxylation; the effect of IAA/HRP is thought to be due in part to the formation of methylene-oxindole, which may conjugate with DNA bases and protein thiols. IAA/HRP could be used as the basis for targeted cancer, a potential new role for plant auxins in cancer therapy (PMID: 11163327).
Indoleacetic acid (IAA) is a breakdown product of tryptophan metabolism and is often produced by the action of bacteria in the mammalian gut. Higher levels of IAA are associated with bacteria from Clostridium species including C. stricklandii, C. lituseburense, C. subterminale, and C. putrefaciens (PMID: 12173102). IAA can be found in Agrobacterium, Azospirillum, Bacillus, Bradyrhizobium, Clostridium, Enterobacter, Pantoea, Pseudomonas, Rhizobium (PMID: 12173102, PMID: 17555270, PMID: 12147474, PMID: 19400643, PMID: 9450337, PMID: 21397014) (https://link.springer.com/chapter/10.1007/978-1-4612-3084-7_7) (https://escholarship.org/uc/item/1bf1b5m3). Some endogenous production of IAA in mammalian tissues also occurs. It may be produced by the decarboxylation of tryptamine or the oxidative deamination of tryptophan. IAA frequently occurs at low levels in urine and has been found in elevated levels in the urine of patients with phenylketonuria (PMID: 13610897). IAA has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Using material extracted from human urine, it was discovered by Kogl in 1933 that indoleacetic acid is also an important plant hormone (PMID: 13610897). Specifically, IAA is a member of the group of phytohormones called auxins. IAA is generally considered to be the most important native auxin. Plant cells synthesize IAA from tryptophan (Wikipedia). IAA and some derivatives can be oxidized by horseradish peroxidase (HRP) into cytotoxic species. IAA is only toxic after oxidative decarboxylation; the effect of IAA/HRP is thought to be due in part to the formation of methylene-oxindole, which may conjugate with DNA bases and protein thiols. IAA/HRP could be used as the basis for targeted cancer, a potential new role for plant auxins in cancer therapy (PMID: 11163327).
Indoleacetic acid (IAA) is a breakdown product of tryptophan metabolism and is often produced by the action of bacteria in the mammalian gut. Higher levels of IAA are associated with bacteria from Clostridium species including C. stricklandii, C. lituseburense, C. subterminale, and C. putrefaciens (PMID: 12173102). IAA can be found in Agrobacterium, Azospirillum, Bacillus, Bradyrhizobium, Clostridium, Enterobacter, Pantoea, Pseudomonas, Rhizobium (PMID: 12173102, PMID: 17555270, PMID: 12147474, PMID: 19400643, PMID: 9450337, PMID: 21397014) (https://link.springer.com/chapter/10.1007/978-1-4612-3084-7_7) (https://escholarship.org/uc/item/1bf1b5m3). Some endogenous production of IAA in mammalian tissues also occurs. It may be produced by the decarboxylation of tryptamine or the oxidative deamination of tryptophan. IAA frequently occurs at low levels in urine and has been found in elevated levels in the urine of patients with phenylketonuria (PMID: 13610897). IAA has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821). Using material extracted from human urine, it was discovered by Kogl in 1933 that indoleacetic acid is also an important plant hormone (PMID: 13610897). Specifically, IAA is a member of the group of phytohormones called auxins. IAA is generally considered to be the most important native auxin. Plant cells synthesize IAA from tryptophan (Wikipedia). IAA and some derivatives can be oxidized by horseradish peroxidase (HRP) into cytotoxic species. IAA is only toxic after oxidative decarboxylation; the effect of IAA/HRP is thought to be due in part to the formation of methylene-oxindole, which may conjugate with DNA bases and protein thiols. IAA/HRP could be used as the basis for targeted cancer, a potential new role for plant auxins in cancer therapy (PMID: 11163327).
Indoleacetyl glutamine is indolic derivative of tryptophan. It is generated from indoleacetic acid. Indoleacetic acid (IAA) is a breakdown product of tryptophan metabolism and is often produced by the action of bacteria in the mammalian gut. Some endogenous production of IAA in mammalian tissues also occurs. It may be produced by the decarboxylation of tryptamine or the oxidative deamination of tryptophan. Indoleacetyl glutamine frequently occurs at low levels in urine and has been found in elevated levels in the urine of patients with hartnup disease, the characteristic symptoms of the disease are mental retardation and pellagra like skin rash.
Indolelactic acid (CAS: 1821-52-9) is a tryptophan metabolite found in human plasma, serum, and urine. Tryptophan is metabolized by two major pathways in humans, either through kynurenine or via a series of indoles, and some of its metabolites are known to be biologically active. Indolelactic acid is present in various amounts, significantly higher in umbilical fetal plasma than in maternal plasma in the protein-bound form (PMID 2361979, 1400722, 3597614, 11060358, 1400722). Indolelactic acid is also a microbial metabolite; urinary indole-3-lactate is produced by Clostridium sporogenes (PMID: 29168502).
Indolelactic acid (CAS: 1821-52-9) is a tryptophan metabolite found in human plasma, serum, and urine. Tryptophan is metabolized by two major pathways in humans, either through kynurenine or via a series of indoles, and some of its metabolites are known to be biologically active. Indolelactic acid is present in various amounts, significantly higher in umbilical fetal plasma than in maternal plasma in the protein-bound form (PMID 2361979, 1400722, 3597614, 11060358, 1400722). Indolelactic acid is also a microbial metabolite; urinary indole-3-lactate is produced by Clostridium sporogenes (PMID: 29168502).
Inosinic acid, also known as inosine monophosphate, IMP, 5'-inosinate or 5'-IMP, belongs to the class of organic compounds known as purine ribonucleoside monophosphates. These are nucleotides consisting of a purine base linked to a ribose to which one monophosphate group is attached. IMP is also classified as a nucleotide (a nucleoside monophosphate). Inosinic acid exists in all living species, ranging from bacteria to plants to humans. IMP is widely used as a flavor enhancer. In the food industry it is known as E number reference E630.  Inosinic acid can be converted into various salts including disodium inosinate (E631), dipotassium inosinate (E632), and calcium inosinate (E633). These three inosinate compounds are used as flavor enhancers for the basic taste umami. These inosinate salts are mostly used in soups, sauces, and seasonings for the intensification and balance of the flavor of meat. Inosinic acid is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid or IMP is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase.  GMP is formed by the inosinate oxidation to xanthylate (XMP). Within humans, inosinic acid participates in a number of enzymatic reactions. In particular, inosinic acid can be converted into phosphoribosyl formamidocarboxamide; which is catalyzed by the bifunctional purine biosynthesis protein. In addition, inosinic acid can be converted into xanthylic acid; which is catalyzed by the enzyme inosine-5'-monophosphate dehydrogenase 1.
Inosinic acid, also known as inosine monophosphate, IMP, 5'-inosinate or 5'-IMP, belongs to the class of organic compounds known as purine ribonucleoside monophosphates. These are nucleotides consisting of a purine base linked to a ribose to which one monophosphate group is attached. IMP is also classified as a nucleotide (a nucleoside monophosphate). Inosinic acid exists in all living species, ranging from bacteria to plants to humans. IMP is widely used as a flavor enhancer. In the food industry it is known as E number reference E630.  Inosinic acid can be converted into various salts including disodium inosinate (E631), dipotassium inosinate (E632), and calcium inosinate (E633). These three inosinate compounds are used as flavor enhancers for the basic taste umami. These inosinate salts are mostly used in soups, sauces, and seasonings for the intensification and balance of the flavor of meat. Inosinic acid is typically obtained from chicken byproducts or other meat industry waste. Inosinic acid or IMP is important in metabolism. It is the ribonucleotide of hypoxanthine and the first nucleotide formed during the synthesis of purine nucleotides. It can also be formed by the deamination of adenosine monophosphate by AMP deaminase.  GMP is formed by the inosinate oxidation to xanthylate (XMP). Within humans, inosinic acid participates in a number of enzymatic reactions. In particular, inosinic acid can be converted into phosphoribosyl formamidocarboxamide; which is catalyzed by the bifunctional purine biosynthesis protein. In addition, inosinic acid can be converted into xanthylic acid; which is catalyzed by the enzyme inosine-5'-monophosphate dehydrogenase 1.
2-Hydroxyethanesulfonate (also known as 2-Hydroxyethanesulfonic acid or isethionic acid) is an organosulfur compound containing a short chain alkane sulfonate linked to a hydroxyl group. It is a water-soluble liquid used in the manufacture of mild, biodegradable, and high-foaming anionic surfactants. These surfactants provide gentle cleansing and a soft skin feel. 2-Hydroxyethanesulfonate forms a colourless, syrupy, and strongly acidic liquid that can form detergents with oleic acid. 2-Hydroxyethanesulfonate is frequently used in the industrial production of taurine. Mammals are also able to endogenously synthesize 2-hydroxyethanesulfonate via taurine through a possible enzymatic deamination process (PMID: 14490797). 2-Hydroxyethanesulfonate can be found in both human plasma and urine (PMID: 1159536, PMID: 6066118). Higher plasma levels of 2-hydroxyethanesulfonate have been shown to be protective against type 2 diabetes.
Isobutyrylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction: acyl-CoA + glycine < -- > CoA + N-acylglycine. Isobutyrylglycine is identified in large amount in urine of patients with isobutyryl-CoA dehydrogenase deficiency. Isobutyryl-CoA dehydrogenase deficiency is a disorder caused by the deficiency of isobutyryl-CoA dehydrogenase that is involved in the catabolism of the branched-chain amino acid valine (PMID 15505379). Moreover, Isobutyrylglycine is found to be associated with ethylmalonic encephalopathy and propionic acidemia, which are also inborn errors of metabolism. Isobutyrylglycine is a biomarker for the consumption of cheese.
Inosine triphosphate (ITP) is an intermediate in the purine metabolism pathway. Relatively high levels of ITP in red cells are found in individuals as result of deficiency of inosine triphosphatase (EC 3.1.3.56, ITPase) ITPase is a cytosolic nucleoside triphosphate pyrophosphohydrolase specific for ITP catalysis to inosine monophosphate (IMP) and deoxy-inosine triphosphate (dITP) to deoxy-inosine monophosphate. ITPase deficiency is not associated with any defined pathology other than the characteristic and abnormal accumulation of ITP in red blood cells. Nevertheless, ITPase deficiency may have pharmacogenomic implications, and the abnormal metabolism of 6-mercaptopurine in ITPase-deficient patients may lead to thiopurine drug toxicity. ITPase's function is not clearly understood but possible roles for ITPase could be to prevent the accumulation of rogue nucleotides which would be otherwise incorporated into DNA and RNA, or compete with nucleotides such as GTP in signalling processes. (PMID: 170291, 1204209, 17113761, 17924837).
Kynurenine is a metabolite of the amino acid tryptophan used in the production of niacin. L-Kynurenine is a central compound of the tryptophan metabolism pathway since it can change into the neuroprotective agent kynurenic acid or to the neurotoxic agent quinolinic acid. The break-up of these endogenous compounds' balance can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. It can also occur in neurodegenerative disorders such as Parkinson's disease, Huntington's, and Alzheimer's disease; and in mental disorders such as schizophrenia and depression.
Kynurenine is a metabolite of the amino acid tryptophan used in the production of niacin. L-Kynurenine is a central compound of the tryptophan metabolism pathway since it can change into the neuroprotective agent kynurenic acid or to the neurotoxic agent quinolinic acid. The break-up of these endogenous compounds' balance can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. It can also occur in neurodegenerative disorders such as Parkinson's disease, Huntington's, and Alzheimer's disease; and in mental disorders such as schizophrenia and depression.
2,4-Diaminobutyric acid, also known as 2,4-diaminobutanoate or Dbu, belongs to the class of organic compounds known as alpha amino acids. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon). 2,4-Diaminobutyric acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. 2,4-Diaminobutyric acid exists in all living organisms, ranging from bacteria to humans. Outside of the human body, 2,4-Diaminobutyric acid has been detected, but not quantified in cow milk. This could make 2,4-diaminobutyric acid a potential biomarker for the consumption of these foods. 2,4-Diaminobutyric acid is a non-physiological, cationic amino acid analogue that is transported into cells by System A with potent antitumoral activity in vitro against human glioma cells, the result of the pronounced concentrated uptake of DAB in glioma cells to the extent that a cellular lysis could occur due to osmotic reasons.
Glutamyllysine is a dipeptide composed of glutamate and lysine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. Glutamyllysine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. The absorption of glutamyllysine is facilitated by the human intestinal oligopeptide transporter (PEPT1) (PMID 16759105).
Glutamyllysine is a dipeptide composed of glutamate and lysine, and is a proteolytic breakdown product of larger proteins. It belongs to the family of N-acyl-alpha amino acids and derivatives. These are compounds containing an alpha amino acid which bears an acyl group at its terminal nitrogen atom. Glutamyllysine is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. The absorption of glutamyllysine is facilitated by the human intestinal oligopeptide transporter (PEPT1) (PMID 16759105).
Alanylglycine is a dipeptide composed of alanine and glycine that is found in human urine. It is a breakdown product from endogenous and exogenous proteins. This peptide is generated by dipeptidyl-dipeptidase (or tetrapeptide dipeptidase) which leads to the release of dipeptides from a tetrapeptide (more specifically: Ala-GlyAla-Gly). The enzyme acts more slowly on Ala-AlaAla-Ala and Gly-GlyGly-Gly.
L-allothreonine is the L-enantiomer of allothreonine. It has a role as an Escherichia coli metabolite and a Saccharomyces cerevisiae metabolite. It is an enantiomer of a D-allothreonine. It is a tautomer of a L-allothreonine zwitterion. Allothreonine is the substrate of the enzyme Serine hydroxymethyltransferase1 (SHMT, EC 2.1.2.1), a human cytoplasmic mRNA binding protein. SHMT uses pyridoxal 5'-phosphate (PLP) and tetrahydropteroylglutamate (H4PteGlu) as coenzymes and catalyzes the reversible interconversion of serine and glycine. In addition to these physiological reactions, SHMT also catalyzes, in the absence of H4PteGlu, the retroaldol cleavage of several 3-hydroxyamino acids, such as allothreonine. Allothreonine is a plant metabolite that appears in the human diet in variable concentrations depending on: plant species, physiological changes during plant growth, senescence, and reactions to environmental stress or to changes due to plant transformation (PMID:10858298, 10952545).
L-Cysteinylglycine disulfide is one of the hydrolysis products of glutathione. Cystinylglycine disulfide is a small peptide replaced cystinylglycine in plasma from patients with homosyctinuria. (PMID: 7333014).
L-Cysteinylglycine disulfide is one of the hydrolysis products of glutathione. Cystinylglycine disulfide is a small peptide replaced cystinylglycine in plasma from patients with homosyctinuria. (PMID: 7333014).
Cystine is an oxidized dimeric form of cysteine. It is formed by linking two cysteine residues via a disulfide bond (Cys-S-S-Cys) between the -SH groups. Cystine is found in high concentrations in digestive enzymes and in the cells of the immune system, skeletal and connective tissues, skin, and hair. Hair and skin are 10-14% cystine. Cystine is the preferred form of cysteine for the synthesis of glutathione in cells involved in the immune system (e.g. macrophages and astrocytes). Lymphocytes and neurons prefer cysteine for glutathione production. Optimizing glutathione levels in macrophages and astrocytes with cystine allows these cells to provide cysteine to lymphocytes and neurons directly upon demand (Wikipedia).
Cystine is an oxidized dimeric form of cysteine. It is formed by linking two cysteine residues via a disulfide bond (Cys-S-S-Cys) between the -SH groups. Cystine is found in high concentrations in digestive enzymes and in the cells of the immune system, skeletal and connective tissues, skin, and hair. Hair and skin are 10-14% cystine. Cystine is the preferred form of cysteine for the synthesis of glutathione in cells involved in the immune system (e.g. macrophages and astrocytes). Lymphocytes and neurons prefer cysteine for glutathione production. Optimizing glutathione levels in macrophages and astrocytes with cystine allows these cells to provide cysteine to lymphocytes and neurons directly upon demand (Wikipedia).
Cystine is an oxidized dimeric form of cysteine. It is formed by linking two cysteine residues via a disulfide bond (Cys-S-S-Cys) between the -SH groups. Cystine is found in high concentrations in digestive enzymes and in the cells of the immune system, skeletal and connective tissues, skin, and hair. Hair and skin are 10-14% cystine. Cystine is the preferred form of cysteine for the synthesis of glutathione in cells involved in the immune system (e.g. macrophages and astrocytes). Lymphocytes and neurons prefer cysteine for glutathione production. Optimizing glutathione levels in macrophages and astrocytes with cystine allows these cells to provide cysteine to lymphocytes and neurons directly upon demand (Wikipedia).
L-Dihydroorotic acid, also known as (S)-4,5-dihydroorotate or dihydro-L-orotate, belongs to the class of organic compounds known as alpha amino acids and derivatives. These are amino acids in which the amino group is attached to the carbon atom immediately adjacent to the carboxylate group (alpha carbon), or a derivative thereof. 4,5-Dihydroorotic acid is a derivative of orotic acid which serves as an intermediate in pyrimidine biosynthesis. L-Dihydroorotic acid is a drug. L-Dihydroorotic acid exists in all living species, ranging from bacteria to humans. Within humans, L-dihydroorotic acid participates in a number of enzymatic reactions. In particular, L-dihydroorotic acid can be biosynthesized from ureidosuccinic acid; which is catalyzed by the enzyme cad protein. In addition, L-dihydroorotic acid and quinone can be converted into orotic acid through the action of the enzyme dihydroorotate dehydrogenase (quinone), mitochondrial. In humans, L-dihydroorotic acid is involved in the metabolic disorder called the beta-ureidopropionase deficiency pathway. Outside of the human body, L-dihydroorotic acid has been detected, but not quantified in several different foods, such as black chokeberries, vanilla, sweet basils, soy beans, and broad beans.
This compound belongs to the family of Butyrophenones. These are compounds containing 1-phenylbutan-1-one moiety.
This compound belongs to the family of Butyrophenones. These are compounds containing 1-phenylbutan-1-one moiety.
Glutamate gamma-methyl ester, also known as L-Glutamic acid 5-methyl ester or g-methyl-L-glutamate (CAS# 1499-55-4) is a white amorphous powder and soluble in water. Its melting point is 182 degree Celsius and should be stored at 2-8 degree Celsius Glutamic acid gamma-methyl ester has been identified in the human placenta (PMID: 32033212).
Oxidized glutathione, also known as glutathione disulfide or GSSG, belongs to the class of organic compounds known as peptides. Peptides are compounds containing an amide derived from two or more amino carboxylic acid molecules (the same or different) by the formation of a covalent bond from the carbonyl carbon of one to the nitrogen atom of another. In humans, oxidized glutathione is involved in the metabolic disorder called leukotriene C4 synthesis deficiency pathway. Outside of the human body, oxidized glutathione has been detected, but not quantified in several different foods, such as leeks, star anises, mamey sapotes, climbing beans, and common persimmons. Oxidized glutathione is a glutathione dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized. Glutathione participates in leukotriene synthesis and is a cofactor for the enzyme glutathione peroxidase. It is also important as a hydrophilic molecule that is added to lipophilic toxins and waste in the liver during biotransformation before they can become part of the bile. Glutathione is also needed for the detoxification of methylglyoxal, a toxin produced as a by-product of metabolism. This detoxification reaction is carried out by the glyoxalase system. Glyoxalase I (EC 4.4.1.5) catalyzes the conversion of methylglyoxal and reduced glutathione into S-D-lactoyl-glutathione. Glyoxalase II (EC 3.1.2.6) catalyzes the hydrolysis of S-D-lactoyl-glutathione into glutathione and D-lactate.
Glycylhydroxyproline is likely a proteolytic breakdown product of collagen. It belongs to the family of peptides. These are compounds containing an amide derived from two or more amino carboxylic acid molecules (the same or different) by the formation of a covalent bond from the carbonyl carbon of one to the nitrogen atom of another. It is found in urine (PMID: 3782411).
4-Hydroxyproline (hydroxyproline or Hyp) is a major component of the protein collagen. Hydroxyproline is produced by hydroxylation of the amino acid proline and is, therefore, a post-translationally modified, non-essential amino acid. Hydroxyproline and proline play key roles in collagen stability. In particular, they permit the sharp twisting of the collagen helix. Hydroxyproline is found in few proteins other than collagen. The only other mammalian protein which includes hydroxyproline is elastin. For this reason, hydroxyproline content has been used as an indicator to determine collagen and/or gelatin amount in tissue or biological samples. Increased serum and urine levels of hydroxyproline have been found in Paget's disease (PMID: 436278). Hydroxyproline (Hyp) content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption or tissue degradation. Bedridden and elderly individuals show significantly elevated serum levels of hydroxyproline in comparison to normal, active individuals (PMID: 10706420). Elevated levels of urinary hydroxyproline are also indicative of muscle damage (PMID: 21988268). Increased reactive oxygen species (ROS) are also known to accelerate collagen degradation. Hydroxyproline levels increase in cases of depression and stress (PMID: 21483218). 4-Hydroxyproline is found to be associated with Alzheimer's disease, and also hydroxyprolinemia and iminoglycinuria which are both inborn errors of metabolism. 4-Hydroxyproline is also involved in metabolic disorders such as hyperprolinemia type I, hyperornithinemia with gyrate atrophy (HOGA), L-arginine:glycine amidinotransferase deficiency, creatine deficiency, and guanidinoacetate methyltransferase deficiency. A deficiency in ascorbic acid can result in impaired hydroxyproline formation (PubChem). trans-4-Hydroxy-L-proline is a biomarker for the consumption of processed meat.
Kynurenine is a metabolite of the amino acid tryptophan used in the production of niacin. L-Kynurenine is a central compound of the tryptophan metabolism pathway since it can change into the neuroprotective agent kynurenic acid or to the neurotoxic agent quinolinic acid. The break-up of these endogenous compounds' balance can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. It can also occur in neurodegenerative disorders such as Parkinson's disease, Huntington's, and Alzheimer's disease; and in mental disorders such as schizophrenia and depression.
Kynurenine is a metabolite of the amino acid tryptophan used in the production of niacin. L-Kynurenine is a central compound of the tryptophan metabolism pathway since it can change into the neuroprotective agent kynurenic acid or to the neurotoxic agent quinolinic acid. The break-up of these endogenous compounds' balance can be observable in many disorders such as stroke, epilepsy, multiple sclerosis, and amyotrophic lateral sclerosis. It can also occur in neurodegenerative disorders such as Parkinson's disease, Huntington's, and Alzheimer's disease; and in mental disorders such as schizophrenia and depression.
Malic acid (CAS: 6915-15-7) is a tart-tasting organic dicarboxylic acid that plays a role in many sour or tart foods. Apples contain malic acid, which contributes to the sourness of a green apple. Malic acid can make a wine taste tart, although the amount decreases with increasing fruit ripeness (Wikipedia). In its ionized form, malic acid is called malate. Malate is an intermediate of the TCA cycle along with fumarate. It can also be formed from pyruvate as one of the anaplerotic reactions. In humans, malic acid is both derived from food sources and synthesized in the body through the citric acid cycle or Krebs cycle which takes place in the mitochondria. Malate's importance to the production of energy in the body during both aerobic and anaerobic conditions is well established. Under aerobic conditions, the oxidation of malate to oxaloacetate provides reducing equivalents to the mitochondria through the malate-aspartate redox shuttle. During anaerobic conditions, where a buildup of excess reducing equivalents inhibits glycolysis, malic acid's simultaneous reduction to succinate and oxidation to oxaloacetate is capable of removing the accumulating reducing equivalents. This allows malic acid to reverse hypoxia's inhibition of glycolysis and energy production. In studies on rats, it has been found that only tissue malate is depleted following exhaustive physical activity. Other key metabolites from the citric acid cycle needed for energy production were found to be unchanged. Because of this, a deficiency of malic acid has been hypothesized to be a major cause of physical exhaustion. Notably, the administration of malic acid to rats has been shown to elevate mitochondrial malate and increase mitochondrial respiration and energy production. Malic acid has been found to be a metabolite in Aspergillus (Hugo Vanden Bossche, D.W.R. Mackenzie and G. Cauwenbergh. Aspergillus and Aspergillosis, 1987).
Malic acid (CAS: 6915-15-7) is a tart-tasting organic dicarboxylic acid that plays a role in many sour or tart foods. Apples contain malic acid, which contributes to the sourness of a green apple. Malic acid can make a wine taste tart, although the amount decreases with increasing fruit ripeness (Wikipedia). In its ionized form, malic acid is called malate. Malate is an intermediate of the TCA cycle along with fumarate. It can also be formed from pyruvate as one of the anaplerotic reactions. In humans, malic acid is both derived from food sources and synthesized in the body through the citric acid cycle or Krebs cycle which takes place in the mitochondria. Malate's importance to the production of energy in the body during both aerobic and anaerobic conditions is well established. Under aerobic conditions, the oxidation of malate to oxaloacetate provides reducing equivalents to the mitochondria through the malate-aspartate redox shuttle. During anaerobic conditions, where a buildup of excess reducing equivalents inhibits glycolysis, malic acid's simultaneous reduction to succinate and oxidation to oxaloacetate is capable of removing the accumulating reducing equivalents. This allows malic acid to reverse hypoxia's inhibition of glycolysis and energy production. In studies on rats, it has been found that only tissue malate is depleted following exhaustive physical activity. Other key metabolites from the citric acid cycle needed for energy production were found to be unchanged. Because of this, a deficiency of malic acid has been hypothesized to be a major cause of physical exhaustion. Notably, the administration of malic acid to rats has been shown to elevate mitochondrial malate and increase mitochondrial respiration and energy production. Malic acid has been found to be a metabolite in Aspergillus (Hugo Vanden Bossche, D.W.R. Mackenzie and G. Cauwenbergh. Aspergillus and Aspergillosis, 1987).
Methionine sulfoximine is found in flours treated with NCl3 as a produced of NCl3 action on wheat protein
Rhamnose (Rham) is a naturally occurring deoxy sugar. It can be classified as either a methyl-pentose or a 6-deoxy-hexose. Rhamnose occurs in nature in its L-form as L-rhamnose (6-deoxy-L-mannose). This is unusual, since most of the naturally occurring sugars are in D-form. Rhamnose is commonly bound to other sugars in nature. It is a common glycone component of glycosides from many plants. Rhamnose is also a component of the outer cell membrane of certain bacteria. L-rhamnose is metabolized to L-Lactaldehyde, which is a branching point in the metabolic pathway of L-fucose and L-rhamnose utilization. It exists in two anomeric forms, alpha-L-rhamnose and beta-L-rhamnose. Rhamnose has been found in Klebsiella, Pseudomonas (https://link.springer.com/article/10.1007/BF00369505) (https://onlinelibrary.wiley.com/doi/abs/10.1002/ejlt.200300816).
Tryptophanamide is a substrate for tryptophan aminopeptidase (EC: 3.5.1.57)and is converted to L-Tryptophan via enzymatic hydrolysis.
Dodecanoic acid, also known as dodecanoate or lauric acid, belongs to the class of organic compounds known as medium-chain fatty acids. These are fatty acids with an aliphatic tail that contains between 4 and 12 carbon atoms. Dodecanoic acid is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Dodecanoic acid is the main fatty acid in coconut oil and in palm kernel oil, and is believed to have antimicrobial properties. It is a white, powdery solid with a faint odour of bay oil. Dodecanoic acid, although slightly irritating to mucous membranes, has a very low toxicity and so is used in many soaps and shampoos.
Levulinic acid is a crystalline keto acid prepared from levulose, inulin, starch, etc., by boiling them with dilute hydrochloric or sulfuric acids.
D-Lysine, also known as D-lysin or DLY, belongs to the class of organic compounds known as d-alpha-amino acids. These are alpha amino acids which have the D-configuration of the alpha-carbon atom. D-Lysine exists in all living organisms, ranging from bacteria to humans. D-Lysine is a potentially toxic compound. The D-enantiomer of the alpha-amino acid lysine.
LysoPC(20:5(5Z,8Z,11Z,14Z,17Z)) is a lysophospholipid (LyP). It is a monoglycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. Lysophosphatidylcholines can have different combinations of fatty acids of varying lengths and saturation attached at the C-1 (sn-1) position. Fatty acids containing 16, 18 and 20 carbons are the most common. LysoPC(20:5(5Z,8Z,11Z,14Z,17Z)), in particular, consists of one chain of eicosapentaenoic acid at the C-1 position. The eicosapentaenoic acid moiety is derived from fish oils, liver and kidney. Lysophosphatidylcholine is found in small amounts in most tissues. It is formed by hydrolysis of phosphatidylcholine by the enzyme phospholipase A2, as part of the de-acylation/re-acylation cycle that controls its overall molecular species composition. It can also be formed inadvertently during extraction of lipids from tissues if the phospholipase is activated by careless handling. In blood plasma significant amounts of lysophosphatidylcholine are formed by a specific enzyme system, lecithin:cholesterol acyltransferase (LCAT), which is secreted from the liver. The enzyme catalyzes the transfer of the fatty acids of position sn-2 of phosphatidylcholine to the free cholesterol in plasma, with formation of cholesterol esters and lysophosphatidylcholine. Lysophospholipids have a role in lipid signaling by acting on lysophospholipid receptors (LPL-R). LPL-R's are members of the G protein-coupled receptor family of integral membrane proteins.
LysoPC(22:4(7Z,10Z,13Z,16Z)) is a lysophospholipid (LyP). It is a monoglycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. Lysophosphatidylcholines can have different combinations of fatty acids of varying lengths and saturation attached at the C-1 (sn-1) position. Fatty acids containing 16, 18 and 20 carbons are the most common. LysoPC(22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of adrenic acid at the C-1 position. The adrenic acid moiety is derived from animal fats. Lysophosphatidylcholine is found in small amounts in most tissues. It is formed by hydrolysis of phosphatidylcholine by the enzyme phospholipase A2, as part of the de-acylation/re-acylation cycle that controls its overall molecular species composition. It can also be formed inadvertently during extraction of lipids from tissues if the phospholipase is activated by careless handling. In blood plasma significant amounts of lysophosphatidylcholine are formed by a specific enzyme system, lecithin:cholesterol acyltransferase (LCAT), which is secreted from the liver. The enzyme catalyzes the transfer of the fatty acids of position sn-2 of phosphatidylcholine to the free cholesterol in plasma, with formation of cholesterol esters and lysophosphatidylcholine. Lysophospholipids have a role in lipid signaling by acting on lysophospholipid receptors (LPL-R). LPL-R's are members of the G protein-coupled receptor family of integral membrane proteins.
LysoPE(0:0/20:2(11Z,14Z)) is a lysophosphatidylethanolamine or a lysophospholipid. The term 'lysophospholipid' (LPL) refers to any phospholipid that is missing one of its two O-acyl chains. Thus, LPLs have a free alcohol in either the sn-1 or sn-2 position. The prefix 'lyso-' comes from the fact that lysophospholipids were originally found to be hemolytic however it is now used to refer generally to phospholipids missing an acyl chain. LPLs are usually the result of phospholipase A-type enzymatic activity on regular phospholipids such as phosphatidylcholine or phosphatidic acid, although they can also be generated by the acylation of glycerophospholipids or the phosphorylation of monoacylglycerols. Some LPLs serve important signaling functions such as lysophosphatidic acid. Lysophosphatidylethanolamines (LPEs) can function as plant growth regulators with several diverse uses. (LPEs) are approved for outdoor agricultural use to accelerate ripening and improve the quality of fresh produce. They are also approved for indoor use to preserve stored crops and commercial cut flowers. As a breakdown product of phosphatidylethanolamine (PE), LPE is present in cells of all organisms.
Maleic acid is a dicarboxylic acid, a molecule with two carboxyl groups. It consists of an ethylene group flanked by two carboxylic acid groups. Maleic acid is the cis isomer of butenedioic acid, whereas fumaric acid is the trans isomer. The cis isomer is the less stable one of the two; the difference in heat of combustion is 22.7 kJ/mol. The physical properties of maleic acid are very different from that of fumaric acid. Maleic acid is soluble in water whereas fumaric acid is not and the melting point of maleic acid (130 - 131 oC) is also much lower than that of fumaric acid (287 oC). Maleic acid is converted into maleic anhydride by dehydration, to malic acid by hydration, and to succinic acid by hydrogenation. Maleic acid is used in making polyesters for fibre-reinforced laminated moldings and paint vehicles. More specifically it is used in the manufacture of phthalic-type alkyd and polyester resins, surface coatings, copolymers, plasticizers, lubricant additives and agricultural chemicals. It is also found in adhesives and sealants and as a preservative for oils and fats. In the natural world, maleic acid has been identified in ginseng, pineapple, cacao plants, sour cherries and corn. A large number of microbes are able to convert maleic acid to D-malate using the enzyme maleate hydratase (PMID: 1444397).
Mesoxalic acid is found in cereals and cereal products. Mesoxalic acid occurs in Medicago sativa (alfalfa). Tentatively identified in rhizosphere of sterile white mustard plants (Sinapis alba
Metanephrine is a metabolite of epinephrine created by action of catechol O-methyltransferase on epinephrine. Technically it is a product of epinephrine O-methylation. It is a commonly occurring, pharmacologically and physiologically inactive metabolite of epinephrine. The measurement of plasma free metanephrines is considered to be the best tool in the diagnosis of pheochromocytoma, a rare kind of adrenal medullary neoplasm. In adrenal chromaffin cells, leakage of norepinephrine and epinephrine from storage granules leads to substantial intracellular production of the O-methylated metabolite metanephrine. In fact, the adrenals constitute the single largest source out of any organ system including the liver for circulating metanephrine. In humans, about 93 percent of circulating metanephrine is derived from catecholamines metabolized within adrenal chromaffin cells. (PMID 15317907).
Methionine sulfone (CAS: 820-10-0), also known as L-methionine-S-dioxide, belongs to the class of organic compounds known as L-alpha-amino acids. These are alpha-amino acids which have the L-configuration at the alpha-carbon atom. Methionine sulfone is a very strong basic compound (based on its pKa). Methionine sulfone has been detected, but not quantified, in garden onions. This could make methionine sulfone a potential biomarker for the consumption of these foods.
Methionine sulfoxide belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. Methionine sulfoxide exists in all living species, ranging from bacteria to humans. Within humans, methionine sulfoxide participates in a number of enzymatic reactions. In particular, methionine sulfoxide can be biosynthesized from L-methionine through its interaction with the enzyme methionine-R-sulfoxide reductase B3. In addition, methionine sulfoxide can be biosynthesized from L-methionine through the action of the enzyme methionine-R-sulfoxide reductase b2, mitochondrial. In humans, methionine sulfoxide is involved in the metabolic disorder called hypermethioninemia.
Methionine sulfoxide belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. Methionine sulfoxide exists in all living species, ranging from bacteria to humans. Within humans, methionine sulfoxide participates in a number of enzymatic reactions. In particular, methionine sulfoxide can be biosynthesized from L-methionine through its interaction with the enzyme methionine-R-sulfoxide reductase B3. In addition, methionine sulfoxide can be biosynthesized from L-methionine through the action of the enzyme methionine-R-sulfoxide reductase b2, mitochondrial. In humans, methionine sulfoxide is involved in the metabolic disorder called hypermethioninemia.
Methylguanidine (MG) is a guanidine in which one of the amino hydrogens of guanidine itself is substituted by a methyl group.  Methylguanidine is a guanidine compound deriving from protein catabolism. It is also a product of putrefaction. Methylguanidine has a role as a metabolite, an EC 1.14.13.39 (nitric oxide synthase) inhibitor and as a uremic toxin. It has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID:22626821). It accumulates in renal failure, however it also exhibits anti-inflammatory effects. Methylguanidine is synthesized from creatinine concomitant with the synthesis of hydrogen peroxide from endogenous substrates in peroxisomes. Recent evidence suggests that methylguanidine significantly inhibits iNOS activity and TNF- release. This means that methylguandine can attenuate the degree of inflammation and tissue damage associated with endotoxic shock.
Methylimidazoleacetic acid is the main metabolite of histamine. This end product of histamine catabolism is formed by N-methylation in the imidazole ring to methylhistamine by histamine methyltransferase (EC 2.1.1.8) and a subsequent oxidative deamination in the side chain by type B monoamine oxidase (EC 1.4.3.4). Based on studies, it is known that as much as 70 to 80 percent of the histamine metabolized in the body is excreted in the urine as methylimidazoleacetic acid. Thus, urinary methylimidazoleacetic acid being the major and specific histamine metabolite is a clear marker of any changes in histamine metabolism in the body. The urinary excretion of methylimidazoleacetic acid is considered a reliable indicator of histamine turnover rate in the body. The excretion of methylimidazoleacetic acid is higher in men than in women. However, this gender difference is abolished when corrected for creatinine excretion. A possible explanation is that basal histamine turnover is related to body size. There is no significant difference in methylimidazoleacetic acid excretion between smokers and non-smokers when analyzing absolute values (mg/24 h). When using methylimidazoleacetic acid values corrected for creatinine excretion female smokers have significantly higher methylimidazoleacetic acid excretion compared to nonsmokers (PMID:11411609, 7130180, 10350179, 10202992).
Methylimidazoleacetic acid is the main metabolite of histamine. This end product of histamine catabolism is formed by N-methylation in the imidazole ring to methylhistamine by histamine methyltransferase (EC 2.1.1.8) and a subsequent oxidative deamination in the side chain by type B monoamine oxidase (EC 1.4.3.4). Based on studies, it is known that as much as 70 to 80 percent of the histamine metabolized in the body is excreted in the urine as methylimidazoleacetic acid. Thus, urinary methylimidazoleacetic acid being the major and specific histamine metabolite is a clear marker of any changes in histamine metabolism in the body. The urinary excretion of methylimidazoleacetic acid is considered a reliable indicator of histamine turnover rate in the body. The excretion of methylimidazoleacetic acid is higher in men than in women. However, this gender difference is abolished when corrected for creatinine excretion. A possible explanation is that basal histamine turnover is related to body size. There is no significant difference in methylimidazoleacetic acid excretion between smokers and non-smokers when analyzing absolute values (mg/24 h). When using methylimidazoleacetic acid values corrected for creatinine excretion female smokers have significantly higher methylimidazoleacetic acid excretion compared to nonsmokers (PMID:11411609, 7130180, 10350179, 10202992).
5'-Methylthioadenosine, also known as MTA or thiomethyladenosine, belongs to the class of organic compounds known as 5'-deoxy-5'-thionucleosides. These are 5'-deoxyribonucleosides in which the ribose is thio-substituted at the 5'position by a S-alkyl group. 5'-Methylthioadenosine is metabolized solely by MTA-phosphorylase, to yield 5-methylthioribose-1-phosphate and adenine, a crucial step in the methionine and purine salvage pathways, respectively. 5'-Methylthioadenosine exists in all living species, ranging from bacteria to humans. 5'-Methylthioadenosine (MTA) is a naturally occurring sulfur-containing nucleoside present in all mammalian tissues. Within humans, 5'-methylthioadenosine participates in a number of enzymatic reactions. In particular, 5'-methylthioadenosine and spermidine can be biosynthesized from S-adenosylmethioninamine and putrescine through the action of the enzyme spermidine synthase. In addition, 5'-methylthioadenosine can be converted into 5-methylthioribose 1-phosphate and L-methionine; which is catalyzed by the enzyme S-methyl-5'-thioadenosine phosphorylase. It is produced from S-adenosylmethionine mainly through the polyamine biosynthetic pathway, where it behaves as a powerful inhibitory product. For instance, 5'-Methylthioadenosine has been shown to influence the regulation of gene expression, proliferation, differentiation, and apoptosis (PMID:15313459). In humans, 5'-methylthioadenosine is involved in the metabolic disorder called hypermethioninemia. Outside of the human body, 5'-Methylthioadenosine has been detected, but not quantified in several different foods, such as soursops, allspices, summer grapes, alaska wild rhubarbs, and breadfruits. Elevated excretion appears in children with severe combined immunodeficiency syndrome (SCID) (PMID:3987052). Evidence suggests that 5'-Methylthioadenosine can affect cellular processes in many ways. 5'-Methylthioadenosine can be found in human urine.
Metoprolol is a selective beta1 receptor blocker used in treatment of several diseases of the cardiovascular system. It is marketed under the brand name Lopressor by Novartis, and Toprol (in the USA); Seleken or Selokeen (elsewhere); A selective adrenergic beta-1-blocking agent with no stimulatory action. It's binding to plasma albumin is weaker than alprenolol and it may be useful in the treatment of several diseases of the cardiovascular system; Metoprolol is a selective beta1 receptor blocker used in treatment of several diseases of the cardiovascular system. It is marketed under the brand name Lopressor by Novartis, and Toprol (in the USA); Seleken or Selokeen (elsewhere); as Minax by Alphapharm (in Australia), as Betaloc by AstraZeneca and as Corvitol by Berlin-Chemie AG; A selective adrenergic beta-1-blocking agent with no stimulatory action. It's binding to plasma albumin is weaker than alprenolol and it may be useful in angina pectoris, hypertension, or cardiac arrhythmias; as Minax by Alphapharm (in Australia), as Betaloc by AstraZeneca and as Corvitol by Berlin-Chemie AG.
Monomethyl glutaric acid, also known as 4-(methoxycarbonyl)butyrate or 2-methyleneglutarate, belongs to the class of organic compounds known as fatty acid methyl esters. Fatty acid methyl esters are compounds containing a fatty acid that is esterified with a methyl group. They have the general structure RC(=O)OR', where R=fatty aliphatic tail or organyl group and R'=methyl group.
N-(1-Deoxy-1-fructosyl)isoleucine is classified as a Natural Food Constituent (code WA) in the DFC.
N-(1-Deoxy-1-fructosyl)methionine is classified as a Natural Food Constituent (code WA) in the DFC.
N-(1-Deoxy-1-fructosyl)phenylalanine is classified as a Natural Food Constituent (code WA) in the DFC.
N-(1-Deoxy-1-fructosyl)tyrosine is classified as a Natural Food Constituent (code WA) in the DFC.
N-(1-Deoxy-1-fructosyl)valine is classified as a Natural Food Constituent (code WA) in the DFC.
N-(1-Deoxy-1-fructosyl)valine is classified as a Natural Food Constituent (code WA) in the DFC.
N-alpha-Acetyl-L-citrulline, also known as N-acetylcitrulline, is an N-acetylated metabolite of citrulline that is part of the arginine biosynthetic pathway. Arginine biosynthesis is notable for its complexity and variability at the genetic level, and by its connection with several other pathways, such as pyrimidine and polyamine biosynthesis, and certain degradative pathways. The initial steps of the arginine biosynthetic pathways proceed via N-acetylated intermediates. The presumed reason for this is that the acetylation prevents the spontaneous cyclization of glutamate derivatives, which leads to proline biosynthesis. N-acetyl-L-ornithine can be transcarbamylated directly by the enzyme acetylornithine transcarbamylase, resulting in N-acetyl-L-citrulline. The enzyme acetylornithine deacetylase can accept N-acetyl-L-citrulline as a substrate and can deacetylate it into citrulline. N-alpha-Acetyl-L-citrulline is found in cases of deficiency of the urea cycle enzyme argininosuccinate synthase (EC 6.3.4.5) that leads to increased concentrations of citrulline and N-acetylcitrulline in the urine (PMID: 14633929).
N-Acetyl-1-methylhistidine belongs to the class of organic compounds known as histidine and derivatives. Histidine and derivatives are compounds containing histidine or a derivative thereof resulting from a reaction of histidine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. N-Acetyl-1-methylhistidine is an acetylated derivative of 1-methylhistidine and a very strong basic compound (based on its pKa). It has been found to be associated with chronic kidney disease: the higher the N-acetyl-1-methylhistidine levels, the lower the estimated glomerular filtration rate. This could make N-acetyl-1-methylhistidine a biomarker for chronic kidney disease (PMID: 24625756).
N-Acetyl-D-Glucosamine (N-acetlyglucosamine) is a monosaccharide derivative of glucose. Chemically it is an amide between glucosamine and acetic acid. A single N-acetlyglucosamine moiety linked to serine or threonine residues on nuclear and cytoplasmic proteins -O-GlcNAc, is an ubiquitous post-translational protein modification. O-GlcNAc modified proteins are involved in sensing the nutrient status of the surrounding cellular environment and adjusting the activity of cellular proteins accordingly. O-GlcNAc regulates cellular responses to hormones such as insulin, initiates a protective response to stress, modulates a cell's capacity to grow and divide, and regulates gene transcription. In humans, it exists in skin, cartilage and blood vessel as a component of hyaluronic acid, and bone tissue, cornea and aorta as a component of keratan sulfate. (PMID 16237703).
N-Acetyl-1-methylhistidine belongs to the class of organic compounds known as histidine and derivatives. Histidine and derivatives are compounds containing histidine or a derivative thereof resulting from a reaction of histidine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. N-Acetyl-1-methylhistidine is an acetylated derivative of 1-methylhistidine and a very strong basic compound (based on its pKa). It has been found to be associated with chronic kidney disease: the higher the N-acetyl-1-methylhistidine levels, the lower the estimated glomerular filtration rate. This could make N-acetyl-1-methylhistidine a biomarker for chronic kidney disease (PMID: 24625756).
N-acetylglucosamine 6-sulfate is a physiological intermediate during the degradation of keratan sulfate and it is usually hydrolyzed intralysosomally by N-acetylglucosamine-6-sulfate sulfatase. (PMID 3161730).
N-Acetyllactosamine, also known as galb1-4glcnacb or lacnac, belongs to the class of organic compounds known as acylaminosugars. These are organic compounds containing a sugar linked to a chain through N-acyl group. N-Acetyllactosamine exists in all living organisms, ranging from bacteria to humans.
N2-Acetylornithine, also known as N(alpha)-acetylornithine, belongs to the class of organic compounds known as N-acyl-L-alpha-amino acids. These are N-acylated alpha-amino acids which have the L-configuration of the alpha-carbon atom. N-Acetylornithine is a minor component of the deproteinized blood plasma of human blood. Human blood plasma contains a variable amount of acetylornithine, averaging 1.1 +/- 0.4 umol/L (range 0.8-0.2 umol/L). Urine contains a very small amount of acetylornithine, approximately 1 nmol/mg creatinine (1 umol/day) (PMID:508804).
Ureidopropionic acid, also known as 3-ureidopropanoate or N-carbamoyl-beta-alanine, belongs to the class of organic compounds known as ureas. Ureas are compounds containing two amine groups joined by a carbonyl (C=O) functional group. Ureidopropionic acid is an intermediate in the metabolism of uracil. More specifically, it is a breakdown product of dihydrouracil and is produced by the enzyme dihydropyrimidase. It is further decomposed into beta-alanine via the enzyme beta-ureidopropionase. Ureidopropionic acid is essentially a urea derivative of beta-alanine. High levels of ureidopropionic acid are found in individuals with beta-ureidopropionase (UP) deficiency (PMID: 11675655). Enzyme deficiencies in pyrimidine metabolism are associated with a risk for severe toxicity against the antineoplastic agent 5-fluorouracil. Ureidopropionic acid has been detected, but not quantified in, several different foods, such as gram beans, broccoli, climbing beans, oriental wheat, and mandarin orange (clementine, tangerine). This could make ureidopropionic acid a potential biomarker for the consumption of these foods.
N-formyl-L-methionine is a L-methionine derivative in which one of the hydrogens attached to the nitrogen is replaced by a formyl group. It has a role as a metabolite. It is a proteinogenic amino acid, a N-formyl amino acid and a L-methionine derivative. It is a conjugate acid of a N-formyl-L-methioninate. N-Formyl-L-methionine belongs to the class of organic compounds known as methionine and derivatives. Methionine and derivatives are compounds containing methionine or a derivative thereof resulting from reaction of methionine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. N-Formyl-L-methionine is effective in the initiation of protein synthesis. The initiating methionine residue enters the ribosome as N-formylmethionyl-tRNA. This process occurs in Escherichia coli and other bacteria as well as in the mitochondria of eukaryotic cells.
N-formyl-L-methionine is a L-methionine derivative in which one of the hydrogens attached to the nitrogen is replaced by a formyl group. It has a role as a metabolite. It is a proteinogenic amino acid, a N-formyl amino acid and a L-methionine derivative. It is a conjugate acid of a N-formyl-L-methioninate. N-Formyl-L-methionine belongs to the class of organic compounds known as methionine and derivatives. Methionine and derivatives are compounds containing methionine or a derivative thereof resulting from reaction of methionine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. N-Formyl-L-methionine is effective in the initiation of protein synthesis. The initiating methionine residue enters the ribosome as N-formylmethionyl-tRNA. This process occurs in Escherichia coli and other bacteria as well as in the mitochondria of eukaryotic cells.
N-Methyl-D-aspartic acid is an amino acid derivative acting as a specific agonist at the NMDA receptor, and therefore mimics the action of the neurotransmitter glutamate on that receptor. In contrast to glutamate, NMDA binds to and regulates the above receptor only, but not other glutamate receptors. NMDA is a water-soluble endogenous metabolite that plays an important role in the neuroendocrine system of species across Animalia (PMID:18096065). It was first synthesized in the 1960s (PMID:14056452). NMDA is an excitotoxin; this trait has applications in behavioural neuroscience research. The body of work utilizing this technique falls under the term "lesion studies." Researchers apply NMDA to specific regions of an (animal) subject's brain or spinal cord and subsequently test for the behaviour of interest, such as operant behaviour. If the behaviour is compromised, it suggests that the destroyed tissue was part of a brain region that made an important contribution to the normal expression of that behaviour. Examples of antagonists of the NMDA receptor are ketamine, amantadine, dextromethorphan (DXM), riluzole, and memantine. They are commonly referred to as NMDA receptor antagonists (PMID:28877137).
N-Methyl-L-proline, also known as N-methyl-L-proline, (2S)-1-methylpyrrolidine-2-carboxylic acid, hydric acid, or monomethyl proline, is classified as a proline or a proline derivative. It is not naturally produced by humans and can only be obtained from the diet. In particular, it is a metabolically inert cell protectant found in many plants and is used by plants to protect against extremes in osmolarity and growth temperatures. N-Methyl-L-proline is found in the fruit juices of yellow orange, blood orange, lemon, mandarin, and bitter orange (PMID: 21838291).
N-Methyl-L-proline, also known as N-methyl-L-proline, (2S)-1-methylpyrrolidine-2-carboxylic acid, hydric acid, or monomethyl proline, is classified as a proline or a proline derivative. It is not naturally produced by humans and can only be obtained from the diet. In particular, it is a metabolically inert cell protectant found in many plants and is used by plants to protect against extremes in osmolarity and growth temperatures. N-Methyl-L-proline is found in the fruit juices of yellow orange, blood orange, lemon, mandarin, and bitter orange (PMID: 21838291).
Phenylacetylglycine is an acyl glycine. Acyl glycines are normally minor metabolites of fatty acids. However, the excretion of certain acyl glycines is increased in several inborn errors of metabolism. In certain cases the measurement of these metabolites in body fluids can be used to diagnose disorders associated with mitochondrial fatty acid beta-oxidation. Acyl glycines are produced through the action of glycine N-acyltransferase (EC 2.3.1.13) which is an enzyme that catalyzes the chemical reaction:. acyl-CoA + glycine < -- > CoA + N-acylglycine. Phenylacetylglycine or PAG is a glycine conjugate of phenylacetic acid. Phenylacetic acid may arise from exposure to styrene (plastic) or through the consumption of fruits and vegetables. Phenylacetic acid is used in some perfumes, possessing a honey-like odour in low concentrations, and is also used in penicillin G production. PAG is a putative biomarker of phospholipidosis. Urinary PAG is elevated in animals exhibiting abnormal phospholipid accumulation in many tissues and may thus be useful as a surrogate biomarker for phospholipidosis. (PMID: 15764292) The presence of phenylacetylglycine in urine has been confirmed for dogs, rats and mice. However, the presence of this compound in human urine is controversial. GC-MS studies have not found this compound (PMID: 7492634) while NMR studies claimed to have identified it (PMID: 21167146). It appears that phenylacetylglycine may sometimes be mistaken for phenylacetylglutamine via NMR.
1-Methyladenosine, also known as M1A, belongs to the class of organic compounds known as purine nucleosides. Purine nucleosides are compounds comprising a purine base attached to a ribosyl or deoxyribosyl moiety. Precise m6A mapping by m6A-CLIP/IP (briefly m6A-CLIP) revealed that a majority of m6A locates in the last exon of mRNAs in multiple tissues/cultured cells of mouse and human, and the m6A enrichment around stop codons is a coincidence that many stop codons locate round the start of last exons where m6A is truly enriched. The methylation of adenosine is directed by a large m6A methyltransferase complex containing METTL3 as the SAM-binding sub-unit. Insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1-3) are reported as a novel class of m6A readers.
1-Methyladenosine, also known as M1A, belongs to the class of organic compounds known as purine nucleosides. Purine nucleosides are compounds comprising a purine base attached to a ribosyl or deoxyribosyl moiety. Precise m6A mapping by m6A-CLIP/IP (briefly m6A-CLIP) revealed that a majority of m6A locates in the last exon of mRNAs in multiple tissues/cultured cells of mouse and human, and the m6A enrichment around stop codons is a coincidence that many stop codons locate round the start of last exons where m6A is truly enriched. The methylation of adenosine is directed by a large m6A methyltransferase complex containing METTL3 as the SAM-binding sub-unit. Insulin-like growth factor-2 mRNA-binding proteins 1, 2, and 3 (IGF2BP1-3) are reported as a novel class of m6A readers.
N2-Fructopyranosylarginine is found in tea. N2-Fructopyranosylarginine is a constituent of Korean red ginseng.
6-Methyladenine is a methylated adenine residue. The formation of internal 6-methyladenine (m6A) residues in eucaryotic messenger RNA (mRNA) is a postsynthetic modification in which S-adenosyl-L-methionine (SAM) serves as the methyl donor. 6-Methyladenine residues have also been localized to heterogeneous nuclear RNA (HnRNA), and for the most part these residues are conserved during mRNA processing. Although the biological significance of internal adenine methylation in eucaryotic mRNA remains unclear, a great deal of research has indicated that this modification may be required for mRNA transport to the cytoplasm, the selection of splice sites or other RNA processing reactions. The presence of m6A residues increases the in vitro translation efficiency of dihydrofolate reductase; an inhibition of m6A residues in dihydrofolate reductase transcripts significantly alters their rate of translation. m6A is found in many human fluids: oviductal fluid, blood plasma and urine (PMID:1551452, 8925412, 10481270, 16083005, 16684535, 3506820, 3728186).
N6,N6,N6-Trimethyl-L-lysine is a methylated derivative of the amino acid lysine. It is a component of histone proteins, a precursor of carnitine and a coenzyme of fatty acid oxidation. N6,N6,N6-Trimethyl-L-lysine residues are found in a number of proteins and are generated by the action of S-adenosyl-L-methionine on exposed lysine residues. When trimethyllysine is released from cognate proteins via proteolysis, it serves as a precursor for carnitine biosynthesis. Mitochondrial 6-N-trimethyllysine dioxygenase converts 6-N-trimethyllysine to 3-hydroxy-6-N-trimethyllysine as the first step for carnitine biosynthesis. Because the subsequent carnitine biosynthesis enzymes are cytosolic, 3-hydroxy-6-N-trimethyllysine must be transported out of the mitochondria by a putative mitochondrial 6-N-trimethyllysine/3-hydroxy-6-N-trimethyllysine transporter system. Plasma -N-trimethyllysine concentrations are significantly lower in systemic carnitine deficiency patients compared to normal individuals, but no significant difference in urinary -N-trimethyllysine excretion is seen between the two groups.
N6,N6,N6-Trimethyl-L-lysine is a methylated derivative of the amino acid lysine. It is a component of histone proteins, a precursor of carnitine and a coenzyme of fatty acid oxidation. N6,N6,N6-Trimethyl-L-lysine residues are found in a number of proteins and are generated by the action of S-adenosyl-L-methionine on exposed lysine residues. When trimethyllysine is released from cognate proteins via proteolysis, it serves as a precursor for carnitine biosynthesis. Mitochondrial 6-N-trimethyllysine dioxygenase converts 6-N-trimethyllysine to 3-hydroxy-6-N-trimethyllysine as the first step for carnitine biosynthesis. Because the subsequent carnitine biosynthesis enzymes are cytosolic, 3-hydroxy-6-N-trimethyllysine must be transported out of the mitochondria by a putative mitochondrial 6-N-trimethyllysine/3-hydroxy-6-N-trimethyllysine transporter system. Plasma -N-trimethyllysine concentrations are significantly lower in systemic carnitine deficiency patients compared to normal individuals, but no significant difference in urinary -N-trimethyllysine excretion is seen between the two groups.
NAD (or nicotinamide adenine dinucleotide) is used extensively in glycolysis and the citric acid cycle of cellular respiration. The reducing potential stored in NADH can be either converted into ATP through the electron transport chain or used for anabolic metabolism. ATP "energy" is necessary for an organism to live. Green plants obtain ATP through photosynthesis, while other organisms obtain it via cellular respiration (Wikipedia). NAD is a coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by a pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH) (Dorland, 27th ed).
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen) respectively. NADH is the reduced form of NAD+, and NAD+ is the oxidized form of NADH. NAD (or nicotinamide adenine dinucleotide) is used extensively in glycolysis and the citric acid cycle of cellular respiration. The reducing potential stored in NADH can be either converted into ATP through the electron transport chain or used for anabolic metabolism. ATP "energy" is necessary for an organism to live. Green plants obtain ATP through photosynthesis, while other organisms obtain it via cellular respiration. NAD is a coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by a pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). NADP is formed through the addition of a phosphate group to the 2' position of the adenosyl nucleotide through an ester linkage.
Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an adenine nucleobase and the other nicotinamide. NAD exists in two forms: an oxidized and reduced form, abbreviated as NAD+ and NADH (H for hydrogen) respectively. NADH is the reduced form of NAD+, and NAD+ is the oxidized form of NADH. NAD (or nicotinamide adenine dinucleotide) is used extensively in glycolysis and the citric acid cycle of cellular respiration. The reducing potential stored in NADH can be either converted into ATP through the electron transport chain or used for anabolic metabolism. ATP "energy" is necessary for an organism to live. Green plants obtain ATP through photosynthesis, while other organisms obtain it via cellular respiration. NAD is a coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by a pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). NADP is formed through the addition of a phosphate group to the 2' position of the adenosyl nucleotide through an ester linkage.
N(6)-Methyllysine is a naturally occurring amino acid found in human biofluids. N-monomethyl-lysine is generated by metabolic transmethylation of endogenous lysine. Lysine methylation displays the highest degree of complexity among known covalent histone modifications, with each site of methylation regulating the association of different effector molecules. The versatility of lysine methylation marks is perhaps best exemplified by modifications implicated in transcriptional regulation as well as being required for double-strand break repair in several organisms. Identification of the numerous biological functions encoded by histone lysine methylation is a major area of research interest, as these mechanisms are intimately associated with cellular senescence, genomic instability, and leukemogenesis. While multiple sites of lysine methylation have been linked with gene activation, each modification is distributed to unique positions across the active gene. (PMID: 17030614, 1122639, 15756599, 3111294).
N(6)-Methyllysine is a naturally occurring amino acid found in human biofluids. N-monomethyl-lysine is generated by metabolic transmethylation of endogenous lysine. Lysine methylation displays the highest degree of complexity among known covalent histone modifications, with each site of methylation regulating the association of different effector molecules. The versatility of lysine methylation marks is perhaps best exemplified by modifications implicated in transcriptional regulation as well as being required for double-strand break repair in several organisms. Identification of the numerous biological functions encoded by histone lysine methylation is a major area of research interest, as these mechanisms are intimately associated with cellular senescence, genomic instability, and leukemogenesis. While multiple sites of lysine methylation have been linked with gene activation, each modification is distributed to unique positions across the active gene. (PMID: 17030614, 1122639, 15756599, 3111294).
Niacinamide, also known as nicotinamide (NAM), is a form of vitamin B3 found in food and used as a dietary supplement and medication. Niacinamide belongs to the class of organic compounds known as nicotinamides. These are heterocyclic aromatic compounds containing a pyridine ring substituted at position 3 by a carboxamide group. Its primary significance is in the prevention and/or cure of blacktongue and pellagra. The structure of nicotinamide consists of a pyridine ring to which a primary amide group is attached in the meta position. It is an amide of nicotinic acid. As an aromatic compound, it undergoes electrophilic substitution reactions and transformations of its two functional groups. Niacinamide and phosphoribosyl pyrophosphate can be converted into nicotinic acid mononucleotide and phosphate by the enzyme nicotinamide phosphoribosyltransferase. In humans, niacinamide is involved in the metabolic disorder called the nad+ signalling pathway (cancer). Niacinamide is an odorless tasting compound. Outside of the human body, niacinamide is found, on average, in the highest concentration within a few different foods, such as common sages, cow milk, and cocoa beans and in a lower concentration in common pea. Niacinamide has also been detected, but not quantified in several different foods, such as yardlong beans, roselles, apples, oyster mushrooms, and swiss chards. Niacinamide occurs in trace amounts mainly in meat, fish, nuts, and mushrooms, as well as to a lesser extent in some vegetables. It is commonly added to cereals and other foods. Many multivitamins contain 20–30 mg of vitamin B3 and it is also available in higher doses. Most animals cannot manufacture this compound in amounts sufficient to prevent nutritional deficiency and it therefore must be supplemented through dietary intake.
Niacinamide, also known as nicotinamide (NAM), is a form of vitamin B3 found in food and used as a dietary supplement and medication. Niacinamide belongs to the class of organic compounds known as nicotinamides. These are heterocyclic aromatic compounds containing a pyridine ring substituted at position 3 by a carboxamide group. Its primary significance is in the prevention and/or cure of blacktongue and pellagra. The structure of nicotinamide consists of a pyridine ring to which a primary amide group is attached in the meta position. It is an amide of nicotinic acid. As an aromatic compound, it undergoes electrophilic substitution reactions and transformations of its two functional groups. Niacinamide and phosphoribosyl pyrophosphate can be converted into nicotinic acid mononucleotide and phosphate by the enzyme nicotinamide phosphoribosyltransferase. In humans, niacinamide is involved in the metabolic disorder called the nad+ signalling pathway (cancer). Niacinamide is an odorless tasting compound. Outside of the human body, niacinamide is found, on average, in the highest concentration within a few different foods, such as common sages, cow milk, and cocoa beans and in a lower concentration in common pea. Niacinamide has also been detected, but not quantified in several different foods, such as yardlong beans, roselles, apples, oyster mushrooms, and swiss chards. Niacinamide occurs in trace amounts mainly in meat, fish, nuts, and mushrooms, as well as to a lesser extent in some vegetables. It is commonly added to cereals and other foods. Many multivitamins contain 20–30 mg of vitamin B3 and it is also available in higher doses. Most animals cannot manufacture this compound in amounts sufficient to prevent nutritional deficiency and it therefore must be supplemented through dietary intake.
Nicotinamide N-oxide is recognized as an in vivo metabolite of nicotinamide which is a precurser of nicotinamide-adenine dinucleotide (NAD+) in animals. The enzyme that catalyses the reduction of nicotinamide N-oxide to nicotinamide in liver is xanthine oxidase.
Nicotinic acid, also known as niacin or vitamin B3, is a water-soluble vitamin whose derivatives such as NADH, NAD, NAD+, and NADP play essential roles in energy metabolism in the living cell and DNA repair. The designation vitamin B3 also includes the amide form, nicotinamide or niacinamide. Severe lack of niacin causes the deficiency disease pellagra, whereas a mild deficiency slows down the metabolism decreasing cold tolerance. The recommended daily allowance of niacin is 2-12 mg a day for children, 14 mg a day for women, 16 mg a day for men, and 18 mg a day for pregnant or breast-feeding women. It is found in various animal and plant tissues and has pellagra-curative, vasodilating, and antilipemic properties. The liver can synthesize niacin from the essential amino acid tryptophan, but the synthesis is extremely slow and requires vitamin B6; 60 mg of tryptophan are required to make one milligram of niacin. Bacteria in the gut may also perform the conversion but are inefficient.
Nicotinic acid, also known as niacin or vitamin B3, is a water-soluble vitamin whose derivatives such as NADH, NAD, NAD+, and NADP play essential roles in energy metabolism in the living cell and DNA repair. The designation vitamin B3 also includes the amide form, nicotinamide or niacinamide. Severe lack of niacin causes the deficiency disease pellagra, whereas a mild deficiency slows down the metabolism decreasing cold tolerance. The recommended daily allowance of niacin is 2-12 mg a day for children, 14 mg a day for women, 16 mg a day for men, and 18 mg a day for pregnant or breast-feeding women. It is found in various animal and plant tissues and has pellagra-curative, vasodilating, and antilipemic properties. The liver can synthesize niacin from the essential amino acid tryptophan, but the synthesis is extremely slow and requires vitamin B6; 60 mg of tryptophan are required to make one milligram of niacin. Bacteria in the gut may also perform the conversion but are inefficient.
Nicotinamide ribotide (NMN) (CAS: 1094-61-7) is an important intermediate metabolite in the nicotinate and nicotinamide metabolism pathway. Mammals predominantly use nicotinamide rather than nicotinic acid as a precursor for NAD biosynthesis. Instead of the deamidation into nicotinic acid, nicotinamide is directly converted into NMN by nicotinamide phosphoribosyltransferase (NAMPT, EC 2.4.2.12). The enzyme nicotinamide mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1), which is a member of the nucleotidyltransferase alpha/beta-phosphodiesterase superfamily, catalyzes the reaction NMN + ATP <=> nicotinamide adenine dinucleotide (NAD) + PPi, representing the final step in the biosynthesis of NAD. NAD is a molecule that plays a fundamental role as a cofactor in cellular redox reactions. Thus NMN is an important metabolite for the maintenance of normal NAD biosynthesis. Circulating NMN levels may play an important role in regulating cell function in physiological and pathophysiological conditions (PMID: 15078171, 17983582).
Norepinephrine is the precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers and of the diffuse projection system in the brain arising from the locus ceruleus. It is also found in plants and is used pharmacologically as a sympathomimetic. Norepinephrine is elevated in the urine of people who consume bananas. Norepinephrine is also a microbial metabolite; urinary noradrenaline is produced by Escherichia, Bacillus, and Saccharomyces (PMID: 24621061). Norepinephrine is found in alcoholic beverages, banana peels and pulp (Musa paradisiaca), red plum fruit (Prunus domestica), orange pulp (Citrus sinensis), potato tubers (Solanum tuberosum), and whole purslane (Portulaca oleracea). P. oleracea is the richest of these sources. Norepinephrine has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
beta-Carboline, also known as norharmane, is an organic amine and is the prototype of a class of compounds known as beta-carbolines. beta-Carbolines are compounds containing a 9H-pyrido[3,4-b]indole moiety. beta-Carboline is a very strong basic compound (based on its pKa). beta-Carboline alkaloids are widely distributed in plants and animals and many are inverse agonists of the GABA-A receptor complex (PMID: 17334612). Other biological activities demonstrated by these compounds include intercalation; inhibition of CDK, topoisomerase, and monoamine oxidase; and interaction with 5-hydroxy serotonin receptors. These compounds have also exhibited sedative, anxiolytic, hypnotic, anticonvulsant, antitumor, antiviral, antiparasitic, and antimicrobial activities (PMID: 17305548).
L-Norleucine, also known as L-aminohexanoate or caprine, belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. Thus, L-norleucine is considered to be a fatty acid lipid molecule. An unnatural amino acid that is used experimentally to study protein structure and function. L-Norleucine is a very hydrophobic molecule, practically insoluble in water, and relatively neutral. L-Norleucine exists in all eukaryotes, ranging from yeast to humans. Outside of the human body, L-Norleucine has been detected, but not quantified in cow milk. This could make L-norleucine a potential biomarker for the consumption of these foods. It binds reversibly to the kringle domain of plasminogen and blocks the binding of plasminogen to fibrin and its activation to plasmin.
N-Acetylhistamine is a 4-(beta-Acetylaminoethyl)imidazole that is an intermediate in Histidine metabolism. It is generated from Histamine via the enzyme Transferases (EC 2.3.1.-). Histamine is an amine derived by enzymatic decarboxylation of histidine. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and also a centrally acting neurotransmitter.
O-Acetylserine is an α-amino acid with the chemical formula HO2CCH(NH2)CH2OC(O)CH3. It is an intermediate in the biosynthesis of the common amino acid cysteine in bacteria and plants. O-Acetylserine is biosynthesized by acetylation of the serine by the enzyme serine transacetylase. The enzyme O-acetylserine (thiol)-lyase, using sulfide sources, converts this ester into cysteine, releasing acetate. O-Acetylserine belongs to the class of organic compounds known as l-alpha-amino acids. These are alpha amino acids which have the L-configuration of the alpha-carbon atom. O-Acetylserine (OASS) is an acylated amino acid derivative. O-Acetylserine exists in all living species, ranging from bacteria to humans. Outside of the human body, O-Acetylserine has been detected, but not quantified in several different foods, such as okra, vaccinium (blueberry, cranberry, huckleberry), rapes, sparkleberries, and lingonberries. This could make O-acetylserine a potential biomarker for the consumption of these foods.
Salicyluric acid is an aryl glycine conjugate formed by the body to eliminate excess salicylates, including aspirin. Aspirin is rapidly hydrolysed to salicylic acid which is further metabolized to various compounds, including salicyluric acid (SU) as well as various acyl and phenolic glucuronides, and hydroxylated metabolites. SU is the major metabolite of SA excreted in urine and it is present in the urine of people who have not taken salicylate drugs, although it has no anti-inflammatory effects in humans or in animals. More salicyluric acid (SU) is excreted in the urine of vegetarians than in non-vegetarians, primarily because fruits and vegetables are important sources of dietary salicylates. However, significantly less (10-15X) SU is excreted by vegetarians than individuals taking low-dose aspirin (PMID: 12944546). The induction of the salicyluric acid formation is one of the saturable pathways of salicylate elimination. The formation of the methyl ester of salicyluric acid is observed during the quantitation of salicyluric acid and other salicylate metabolites in urine by high-pressure liquid chromatography. This methyl ester formation causes artificially low values for salicyluric acid and high values for salicylic acid. (PMID: 6101164, 6857178). Salicyluric acid has been found to be a microbial metabolite.
Phosphothreonine is a phosphoamino acid. It is the phosphorylated ester of threonine. There are three amino acids that are typically phosphorylated in eukaryotes: serine, threonine, and tyrosine. Threonine residues in endogenous proteins undergo phosphorylation through the action of a threonine kinase. Small amounts of free phosphothreonine can be detected in urine [PMID: 7693088].
p-Octopamine is an amine in traces quantities in plasma and cerebrospinal fluid in humans with septic encephalopathy (PMID 15932098).
D-Ornithine is an amino acid produced in the urea cycle by the splitting off of urea from arginine. Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen. D-Ornithine has been identified in the human placenta (PMID: 32033212).
D-Ornithine is an amino acid produced in the urea cycle by the splitting off of urea from arginine. Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen. D-Ornithine has been identified in the human placenta (PMID: 32033212).
D-Ornithine is an amino acid produced in the urea cycle by the splitting off of urea from arginine. Ornithine is one of the products of the action of the enzyme arginase on L-arginine, creating urea. Therefore, ornithine is a central part of the urea cycle, which allows for the disposal of excess nitrogen. D-Ornithine has been identified in the human placenta (PMID: 32033212).
Orotidine is a nucleoside formed by attaching orotic acid to a ribose ring via a beta-N1-glycosidic bond. It is a water-soluble solid.  Orotidine is found in bacteria, fungi, plants, and animals.  In humans, orotidine occurs as its 5'-phosphate (orotidylic acid), which is an intermediate in the biosynthesis of pyrimidine nucleosides (cytidine and uridine) that are found in nucleic acids (as the nucleotides containing the bases cytosine and uracil). Orotidine itself is not a component of nucleic acid.  Orotidine monophosphate (OMP) is converted to uridine monophosphate by OMP decarboxylase, which is inhibited by mononucleotide precursors.  Large amounts of orotidine are excreted in the urine of cancer patients treated with 6-azauridine, which is one such inhibitor, indicating that the subject has increased DNA synthesis due to cancer.  Orotidine was first isolated from a mutant strain of the fungus Neurospora by A. Michael Michelson, William Drell, and Herschel K. Mitchell (PMID: 14853953).
Orotidine is a nucleoside formed by attaching orotic acid to a ribose ring via a beta-N1-glycosidic bond. It is a water-soluble solid.  Orotidine is found in bacteria, fungi, plants, and animals.  In humans, orotidine occurs as its 5'-phosphate (orotidylic acid), which is an intermediate in the biosynthesis of pyrimidine nucleosides (cytidine and uridine) that are found in nucleic acids (as the nucleotides containing the bases cytosine and uracil). Orotidine itself is not a component of nucleic acid.  Orotidine monophosphate (OMP) is converted to uridine monophosphate by OMP decarboxylase, which is inhibited by mononucleotide precursors.  Large amounts of orotidine are excreted in the urine of cancer patients treated with 6-azauridine, which is one such inhibitor, indicating that the subject has increased DNA synthesis due to cancer.  Orotidine was first isolated from a mutant strain of the fungus Neurospora by A. Michael Michelson, William Drell, and Herschel K. Mitchell (PMID: 14853953).
Orotidine is a nucleoside formed by attaching orotic acid to a ribose ring via a beta-N1-glycosidic bond. It is a water-soluble solid.  Orotidine is found in bacteria, fungi, plants, and animals.  In humans, orotidine occurs as its 5'-phosphate (orotidylic acid), which is an intermediate in the biosynthesis of pyrimidine nucleosides (cytidine and uridine) that are found in nucleic acids (as the nucleotides containing the bases cytosine and uracil). Orotidine itself is not a component of nucleic acid.  Orotidine monophosphate (OMP) is converted to uridine monophosphate by OMP decarboxylase, which is inhibited by mononucleotide precursors.  Large amounts of orotidine are excreted in the urine of cancer patients treated with 6-azauridine, which is one such inhibitor, indicating that the subject has increased DNA synthesis due to cancer.  Orotidine was first isolated from a mutant strain of the fungus Neurospora by A. Michael Michelson, William Drell, and Herschel K. Mitchell (PMID: 14853953).
Oxalic acid is a strong dicarboxylic acid occurring in many plants and vegetables. It is produced in the body by metabolism of glyoxylic acid or ascorbic acid. It is not metabolized but excreted in the urine. It is used as an analytical reagent and general reducing agent (Pubchem). Oxalic acid (IUPAC name: ethanedioic acid, formula H2C2O4) is a dicarboxylic acid with structure (HOOC)-(COOH). Because of the joining of two carboxyl groups, this is one of the strongest organic acids. It is also a reducing agent. The anions of oxalic acid as well as its salts and esters are known as oxalates (Wikipedia). Bodily oxalic acid may also be synthesized via the metabolism of either glyoxylic acid or unused ascorbic acid (vitamin C), which is a serious health consideration for long term megadosers of vitamin C supplements. 80% of kidney stones are formed from calcium oxalate. Some Aspergillus species produce oxalic acid, which reacts with blood or tissue calcium to precipitate calcium oxalate. There is some preliminary evidence that the administration of probiotics can affect oxalic acid excretion rates (and presumably oxalic acid levels as well) (Wikipedia). Oxalic acid is found to be associated with fumarase deficiency and primary hyperoxaluria I, which are inborn errors of metabolism. Oxalic acid is a marker for yeast overgrowth from Aspergillus, Penicillum and/or Candida. Can also be elevated due to exposures from vitamin C or ethylene glycol poisoning. Oxalate is elevated in the urine of children with autism. (PMID: 21911305). Oxalic acid has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
Oxalic acid is a strong dicarboxylic acid occurring in many plants and vegetables. It is produced in the body by metabolism of glyoxylic acid or ascorbic acid. It is not metabolized but excreted in the urine. It is used as an analytical reagent and general reducing agent (Pubchem). Oxalic acid (IUPAC name: ethanedioic acid, formula H2C2O4) is a dicarboxylic acid with structure (HOOC)-(COOH). Because of the joining of two carboxyl groups, this is one of the strongest organic acids. It is also a reducing agent. The anions of oxalic acid as well as its salts and esters are known as oxalates (Wikipedia). Bodily oxalic acid may also be synthesized via the metabolism of either glyoxylic acid or unused ascorbic acid (vitamin C), which is a serious health consideration for long term megadosers of vitamin C supplements. 80% of kidney stones are formed from calcium oxalate. Some Aspergillus species produce oxalic acid, which reacts with blood or tissue calcium to precipitate calcium oxalate. There is some preliminary evidence that the administration of probiotics can affect oxalic acid excretion rates (and presumably oxalic acid levels as well) (Wikipedia). Oxalic acid is found to be associated with fumarase deficiency and primary hyperoxaluria I, which are inborn errors of metabolism. Oxalic acid is a marker for yeast overgrowth from Aspergillus, Penicillum and/or Candida. Can also be elevated due to exposures from vitamin C or ethylene glycol poisoning. Oxalate is elevated in the urine of children with autism. (PMID: 21911305). Oxalic acid has also been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
1,3-Dihydro-(2H)-indol-2-one, also known as 2-oxindole or 2-indolinone, belongs to the class of organic compounds known as indolines. Indolines are compounds containing an indole moiety, which consists of pyrrolidine ring fused to benzene to form 2,3-dihydroindole.
8-oxo-dgdp is part of the Purine metabolism pathway. It is a substrate for: ADP-sugar pyrophosphatase.
8-Oxo-dGMP is a metabolite of 8-oxo-dGTP. 8-Oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate (8-oxo-dGTP) is a potent mutagenic substrate for DNA synthesis. 8-Oxo-dGTP is rapidly degraded to 8-oxo-dGMP by cellular 8-oxo-dGTPase activity. 8-Oxo-dGMP is further degraded to 8-oxo-deoxyguanosine by a nucleotidase. 8-Oxo-dGMP is the most preferred substrate of this nucleotidase enzyme (PMID: 7819228). The human MutT homologue (hMTH1), an 8-oxo-dGTPase, prevents misincorporation of 8-oxo-dGTP into DNA by hydrolyzing it to 8-oxo-dGMP. hMTH1 mRNA is overexpressed in human renal cell carcinomas and breast tumors. Likewise, elevated levels of hMTH1 protein have also been detected in brain tumors. (PMID: 12757855).
8-Oxo-dGTP is considered a potentially dangerous intermediate which promotes AT-to-CG transversions in nucleoside phosphate metabolic pathways (PMID: 9822604). Nudix (nucleoside diphosphate linked moiety X) proteins act as homeostatic checkpoints at important stages in nucleoside phosphate metabolic pathways, guarding against elevated levels of potentially dangerous intermediates (e.g. 8-Oxo-dGTP). NUDT3 (Nudix-type motif 3) is an example of a MutT, or Nudix, protein family member. (Wikipedia). Misincorporation of oxidized nucleoside triphosphates into DNA/RNA during replication and transcription can cause mutations that may result in carcinogenesis or neurodegeneration. The protein encoded by this gene is an enzyme that hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP, 8-oxo-dATP, 2-hydroxy-dATP, and 2-hydroxy rATP, to monophosphates, thereby preventing misincorporation. The encoded protein is localized mainly in the cytoplasm, with some in the mitochondria, suggesting that it is involved in the sanitization of nucleotide pools both for nuclear and mitochondrial genomes. Several alternatively spliced transcript variants, some of which encode distinct isoforms, have been identified. Additional variants have been observed, but their full-length natures have not been determined. (Wikipedia).
8-Oxo-dGTP is considered a potentially dangerous intermediate which promotes AT-to-CG transversions in nucleoside phosphate metabolic pathways (PMID: 9822604). Nudix (nucleoside diphosphate linked moiety X) proteins act as homeostatic checkpoints at important stages in nucleoside phosphate metabolic pathways, guarding against elevated levels of potentially dangerous intermediates (e.g. 8-Oxo-dGTP). NUDT3 (Nudix-type motif 3) is an example of a MutT, or Nudix, protein family member. (Wikipedia). Misincorporation of oxidized nucleoside triphosphates into DNA/RNA during replication and transcription can cause mutations that may result in carcinogenesis or neurodegeneration. The protein encoded by this gene is an enzyme that hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP, 8-oxo-dATP, 2-hydroxy-dATP, and 2-hydroxy rATP, to monophosphates, thereby preventing misincorporation. The encoded protein is localized mainly in the cytoplasm, with some in the mitochondria, suggesting that it is involved in the sanitization of nucleotide pools both for nuclear and mitochondrial genomes. Several alternatively spliced transcript variants, some of which encode distinct isoforms, have been identified. Additional variants have been observed, but their full-length natures have not been determined. (Wikipedia).
4-Hydroxycinnamic acid, also known as p-Coumaric acid, is a coumaric acid in which the hydroxy substituent is located at C-4 of the phenyl ring. It has a role as a plant metabolite. It is a conjugate acid of a 4-coumarate. p-coumaric acid is an organic compound that is a hydroxy derivative of cinnamic acid. There are three isomers of coumaric acid: o-coumaric acid, m-coumaric acid, and p-coumaric acid, that differ by the position of the hydroxy substitution of the phenyl group. p-Coumaric acid is the most abundant isomer of the three in nature. p-Coumaric acid exists in two forms trans-p-coumaric acid and cis-p-coumaric acid. It is a crystalline solid that is slightly soluble in water, but very soluble in ethanol and diethyl ether. 4-Hydroxycinnamic acid belongs to the class of organic compounds known as hydroxycinnamic acids. Hydroxycinnamic acids are compounds containing an cinnamic acid where the benzene ring is hydroxylated. 4-Hydroxycinnamic acid exists in all living species, ranging from bacteria to humans. Outside of the human body, 4-Hydroxycinnamic acid is found, on average, in the highest concentration within a few different foods, such as pepper (Capsicum frutescens), pineapples, and sunflowers and in a lower concentration in spinachs, kiwis, and sweet oranges. 4-Hydroxycinnamic acid has also been detected, but not quantified in several different foods, such as wild rices, soursops, garden onions, hyssops, and avocado.
Pantothenic acid, also called vitamin B5, is a water-soluble vitamin required to sustain life. Pantothenic acid is needed to form coenzyme-A (CoA), and is thus critical in the metabolism and synthesis of carbohydrates, proteins, and fats. Its name is derived from the Greek pantothen meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food, with high amounts in whole grain cereals, legumes, eggs, meat, and royal jelly. Pantothenic acid is classified as a member of the secondary alcohols. Secondary alcohols are compounds containing a secondary alcohol functional group, with the general structure HOC(R)(R') (R,R'=alkyl, aryl). Pantothenic acid is considered to be soluble (in water) and acidic.
Pantothenic acid, also called vitamin B5, is a water-soluble vitamin required to sustain life. Pantothenic acid is needed to form coenzyme-A (CoA), and is thus critical in the metabolism and synthesis of carbohydrates, proteins, and fats. Its name is derived from the Greek pantothen meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food, with high amounts in whole grain cereals, legumes, eggs, meat, and royal jelly. Pantothenic acid is classified as a member of the secondary alcohols. Secondary alcohols are compounds containing a secondary alcohol functional group, with the general structure HOC(R)(R') (R,R'=alkyl, aryl). Pantothenic acid is considered to be soluble (in water) and acidic.
Pantothenic acid, also called vitamin B5, is a water-soluble vitamin required to sustain life. Pantothenic acid is needed to form coenzyme-A (CoA), and is thus critical in the metabolism and synthesis of carbohydrates, proteins, and fats. Its name is derived from the Greek pantothen meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food, with high amounts in whole grain cereals, legumes, eggs, meat, and royal jelly. Pantothenic acid is classified as a member of the secondary alcohols. Secondary alcohols are compounds containing a secondary alcohol functional group, with the general structure HOC(R)(R') (R,R'=alkyl, aryl). Pantothenic acid is considered to be soluble (in water) and acidic.
Paracetamol sulfate, also known as paracetamol sulfuric acid or 4-acetaminophen sulfate, is classified as a phenylsulfate. Phenylsulfates are compounds containing a sulfuric acid group conjugated to a phenyl group. Paracetamol sulfate is considered a slightly soluble (in water), acidic compound. Paracetamol sulfate is a metabolite of paracetamol, a common drug used for the relief of pain as an antipyretic. After paracetamol is absorbed from the gastrointestinal tract, it forms paracetamol sulfate by conjugation with sulfuric acid. Paracetamol sulfate can be found in both plasma and urine (PMID: 15127815).
PC(14:0/18:1(11Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(14:0/18:1(11Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of vaccenic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the vaccenic acid moiety is derived from butter fat and animal fat. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/18:1(11Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/18:1(11Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of vaccenic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the vaccenic acid moiety is derived from butter fat and animal fat. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/18:4(6Z,9Z,12Z,15Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/18:4(6Z,9Z,12Z,15Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of stearidonic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the stearidonic acid moiety is derived from seed oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/18:4(6Z,9Z,12Z,15Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/18:4(6Z,9Z,12Z,15Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of stearidonic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the stearidonic acid moiety is derived from seed oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(14:0/20:2(11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(14:0/20:2(11Z,14Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of eicosadienoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the eicosadienoic acid moiety is derived from fish oils and liver. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(14:0/20:4(5Z,8Z,11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(14:0/20:4(5Z,8Z,11Z,14Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of arachidonic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the arachidonic acid moiety is derived from animal fats and eggs. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/20:2(11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/20:2(11Z,14Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of eicosadienoic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the eicosadienoic acid moiety is derived from fish oils and liver. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/20:4(5Z,8Z,11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/20:4(5Z,8Z,11Z,14Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of arachidonic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the arachidonic acid moiety is derived from animal fats and eggs. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/20:4(5Z,8Z,11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/20:4(5Z,8Z,11Z,14Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of arachidonic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the arachidonic acid moiety is derived from animal fats and eggs. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/20:4(5Z,8Z,11Z,14Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/20:4(5Z,8Z,11Z,14Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of arachidonic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the arachidonic acid moiety is derived from animal fats and eggs. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(18:1(9Z)/18:1(9Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(18:1(9Z)/18:1(9Z)), in particular, consists of two chains of oleic acid at the C-1 and C-2 positions. The oleic acid moieties are derived from vegetable oils, especially olive and canola oil. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. Dioleoylphosphatidylcholine is found in human platelets and red blood cells, in mitochondria from skeletal muscle, lung, umbilical artery and vein endothelial cells (PMID: 15351277, 7138900, 2351875, 4046747, 2755318).While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(14:0/22:4(7Z,10Z,13Z,16Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(14:0/22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of adrenic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the adrenic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(14:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(14:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(15:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(15:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of pentadecanoic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The pentadecanoic acid moiety is derived from dairy products and milk fat, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(16:0/22:4(7Z,10Z,13Z,16Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(16:0/22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of adrenic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the adrenic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(16:0/22:4(7Z,10Z,13Z,16Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(16:0/22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of adrenic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the adrenic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of stearic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The stearic acid moiety is derived from animal fats, coco butter and sesame oil, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(18:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of stearic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The stearic acid moiety is derived from animal fats, coco butter and sesame oil, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PC(16:1(9Z)/18:3(6Z,9Z,12Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(16:1(9Z)/18:3(6Z,9Z,12Z)), in particular, consists of one chain of palmitoleic acid at the C-1 position and one chain of g-linolenic acid at the C-2 position. The palmitoleic acid moiety is derived from animal fats and vegetable oils, while the g-linolenic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
Chenodeoxycholoyl-CoA is bile acid Coenzyme A ester. In humans, bile acids conjugated with glycine and taurine are the major solutes in bile, and unconjugated bile acids are almost nondetectable in normal bile. Conjugated bile acids are less toxic and are more efficient promoters of intestinal absorption of dietary lipid than unconjugated bile acids. The synthesis of bile acid and amino acid conjugates in human liver is the result of two independent enzymatic reactions with a bile acid coenzyme A thioester intermediate formation of bile acid-CoA esters, considered the rate-limiting step in bile acid amidation and catalyzed by an ATP-dependent microsomal enzyme, bile acid-CoA synthetase (EC 6.2.1.7). In the second reaction, the thioester bond is cleaved, and an amide bond is formed between the bile acid and the amino acids glycine or taurine. The bile acid-CoA:amino acid N-acyltransferase (EC 2.3.1.65) catalyzes this reaction in the cytosol prior to secretion into bile. In human liver the formation of bile acid-CoA thioesters is localized both to the microsomal fraction catalysed by an ATP-dependent synthetase and to the peroxisomal fraction catalysed by the thiolase in the last step of the beta-oxidative cleavage of the 5beta-cholestanoyl side chain. The highest specific amidation activity of both chenodeoxycholoyl-CoA is always found in the most peroxisome-rich subcellular fractions. (PMID: 2722825, 10817395, 11673457, 10884298).
Chenodeoxycholoyl-CoA is bile acid Coenzyme A ester. In humans, bile acids conjugated with glycine and taurine are the major solutes in bile, and unconjugated bile acids are almost nondetectable in normal bile. Conjugated bile acids are less toxic and are more efficient promoters of intestinal absorption of dietary lipid than unconjugated bile acids. The synthesis of bile acid and amino acid conjugates in human liver is the result of two independent enzymatic reactions with a bile acid coenzyme A thioester intermediate formation of bile acid-CoA esters, considered the rate-limiting step in bile acid amidation and catalyzed by an ATP-dependent microsomal enzyme, bile acid-CoA synthetase (EC 6.2.1.7). In the second reaction, the thioester bond is cleaved, and an amide bond is formed between the bile acid and the amino acids glycine or taurine. The bile acid-CoA:amino acid N-acyltransferase (EC 2.3.1.65) catalyzes this reaction in the cytosol prior to secretion into bile. In human liver the formation of bile acid-CoA thioesters is localized both to the microsomal fraction catalysed by an ATP-dependent synthetase and to the peroxisomal fraction catalysed by the thiolase in the last step of the beta-oxidative cleavage of the 5beta-cholestanoyl side chain. The highest specific amidation activity of both chenodeoxycholoyl-CoA is always found in the most peroxisome-rich subcellular fractions. (PMID: 2722825, 10817395, 11673457, 10884298).
PC(O-22:1(13Z)/20:4(8Z,11Z,14Z,17Z)) is a phosphatidylcholine (PC or GPCho). It is a glycerophospholipid in which a phosphorylcholine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphocholines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PC(O-22:1(13Z)/20:4(8Z,11Z,14Z,17Z)), in particular, consists of one chain of Erucyl alcohol at the C-1 position and one chain of eicosatetraenoic acid at the C-2 position. The Erucyl alcohol moiety is derived from Rapeseed oil, while the eicosatetraenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling. While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PCs can be synthesized via three different routes. In one route, choline is activated first by phosphorylation and then by coupling to CDP prior to attachment to phosphatidic acid. PCs can also synthesized by the addition of choline to CDP-activated 1,2-diacylglycerol. A third route to PC synthesis involves the conversion of either PS or PE to PC.
PE(14:0/20:1(11Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:0/20:1(11Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of eicosenoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the eicosenoic acid moiety is derived from vegetable oils and cod oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(14:0/20:2(11Z,14Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:0/20:2(11Z,14Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of eicosadienoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the eicosadienoic acid moiety is derived from fish oils and liver. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(14:0/22:2(13Z,16Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:0/22:2(13Z,16Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of docosadienoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the docosadienoic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(14:1(9Z)/22:2(13Z,16Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:1(9Z)/22:2(13Z,16Z)), in particular, consists of one chain of myristoleic acid at the C-1 position and one chain of docosadienoic acid at the C-2 position. The myristoleic acid moiety is derived from milk fats, while the docosadienoic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(14:0/22:4(7Z,10Z,13Z,16Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:0/22:4(7Z,10Z,13Z,16Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of adrenic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the adrenic acid moiety is derived from animal fats. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(14:0/22:5(4Z,7Z,10Z,13Z,16Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(14:0/22:5(4Z,7Z,10Z,13Z,16Z)), in particular, consists of one chain of myristic acid at the C-1 position and one chain of docosapentaenoic acid at the C-2 position. The myristic acid moiety is derived from nutmeg and butter, while the docosapentaenoic acid moiety is derived from animal fats and brain. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(16:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of docosahexaenoic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the docosahexaenoic acid moiety is derived from fish oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(18:1(11Z)/18:1(9Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(18:1(11Z)/18:1(9Z)), in particular, consists of one chain of vaccenic acid at the C-1 position and one chain of oleic acid at the C-2 position. The vaccenic acid moiety is derived from butter fat and animal fat, while the oleic acid moiety is derived from vegetable oils, especially olive and canola oil. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(18:1(9Z)/18:4(6Z,9Z,12Z,15Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(18:1(9Z)/18:4(6Z,9Z,12Z,15Z)), in particular, consists of one chain of oleic acid at the C-1 position and one chain of stearidonic acid at the C-2 position. The oleic acid moiety is derived from vegetable oils, especially olive and canola oil, while the stearidonic acid moiety is derived from seed oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(18:1(9Z)/20:3(5Z,8Z,11Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(18:1(9Z)/20:3(5Z,8Z,11Z)), in particular, consists of one chain of oleic acid at the C-1 position and one chain of mead acid at the C-2 position. The oleic acid moiety is derived from vegetable oils, especially olive and canola oil, while the mead acid moiety is derived from fish oils, liver and kidney. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
Hydroxyclomipramine is a metabolite of clomipramine. Clomipramine (trademarked as Anafranil) is a tricyclic antidepressant (TCA). It was developed in the 1960s by the Swiss drug manufacturer Geigy (now known as Novartis) and has been in clinical use worldwide ever since. (Wikipedia)
Hydroxyclomipramine is a metabolite of clomipramine. Clomipramine (trademarked as Anafranil) is a tricyclic antidepressant (TCA). It was developed in the 1960s by the Swiss drug manufacturer Geigy (now known as Novartis) and has been in clinical use worldwide ever since. (Wikipedia)
PE(20:4(5Z,8Z,11Z,14Z)/18:2(9Z,12Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(20:4(5Z,8Z,11Z,14Z)/18:2(9Z,12Z)), in particular, consists of one chain of arachidonic acid at the C-1 position and one chain of linoleic acid at the C-2 position. The arachidonic acid moiety is derived from animal fats and eggs, while the linoleic acid moiety is derived from seed oils. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(20:3(5Z,8Z,11Z)/20:3(5Z,8Z,11Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(20:3(5Z,8Z,11Z)/20:3(5Z,8Z,11Z)), in particular, consists of two chains of mead acid at the C-1 and C-2 positions. The mead acid moieties are derived from fish oils, liver and kidney. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
PE(20:3(5Z,8Z,11Z)/20:3(5Z,8Z,11Z)) is a phosphatidylethanolamine (PE or GPEtn). It is a glycerophospholipid in which a phosphorylethanolamine moiety occupies a glycerol substitution site. As is the case with diacylglycerols, glycerophosphoethanolamines can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 16, 18 and 20 carbons are the most common. PE(20:3(5Z,8Z,11Z)/20:3(5Z,8Z,11Z)), in particular, consists of two chains of mead acid at the C-1 and C-2 positions. The mead acid moieties are derived from fish oils, liver and kidney. Phospholipids, are ubiquitous in nature and are key components of the lipid bilayer of cells, as well as being involved in metabolism and signaling.While most phospholipids have a saturated fatty acid on C-1 and an unsaturated fatty acid on C-2 of the glycerol backbone, the fatty acid distribution at the C-1 and C-2 positions of glycerol within phospholipids is continually in flux, owing to phospholipid degradation and the continuous phospholipid remodeling that occurs while these molecules are in membranes. PEs are neutral zwitterions at physiological pH. They mostly have palmitic or stearic acid on carbon 1 and a long chain unsaturated fatty acid (e.g. 18:2, 20:4 and 22:6) on carbon 2. PE synthesis can occur via two pathways. The first requires that ethanolamine be activated by phosphorylation and then coupled to CDP. The ethanolamine is then transferred from CDP-ethanolamine to phosphatidic acid to yield PE. The second involves the decarboxylation of PS.
Pelargonidin, also known as pelargonidin chloride (CAS: 134-04-3) is an anthocyanin. Anthocyanins are water-soluble glycosides and acylglycosides of anthocyanidins, which are polyhydroxy and polymethoxyl derivatives of a 2-phenylbenzopyrylium (flavylium) cation. They are widely distributed in foods of plant origin, especially in fruits and vegetables with dark red and blue colours. Numerous epidemiologic and clinical trials show that fruits and vegetables, many of which are rich in anthocyanins, may be related to the decreased incidence of many chronic and degenerative diseases, including heart disease, cancer, and aging. Antioxidant mechanisms were suggested as potential means of disease prevention. Anthocyanins are strong antioxidants in vitro. In most cases, fruits and vegetables with high anthocyanin content were shown to have higher antioxidant capacity than other fruits and vegetables. Whether anthocyanins are effective antioxidants in vivo remains an open question primarily because of the relatively low apparent absorption of anthocyanins compared with other phenolic compounds (PMID: 15465754). BioTransformer predicts that pelargonidin is a product of 5-[(6-{[(2-carboxyacetyl)oxy]methyl}-3,4,5-trihydroxyoxan-2-yl)oxy]-3,7-dihydroxy-2-(4-hydroxyphenyl)-1λ⁴-chromen-1-ylium metabolism via a glycoside-hydrolysis reaction occurring in human gut microbiota and catalyzed by an EC.3.2.1.X enzyme (PMID: 30612223).
Phenol, is a toxic, colourless crystalline solid with a sweet tarry odor that resembles a hospital smell. It is commonly used as an antiseptic and disinfectant. It is active against a wide range of micro-organisms including some fungi and viruses, but is only slowly effective against spores. It has been used to disinfect skin and to relieve itching. Phenol is also used in the preparation of cosmetics including sunscreens, hair dyes, and skin lightening preparations. It is also used in the production of drugs (it is the starting material in the industrial production of aspirin), weedkillers, and synthetic resins. Phenol can be found in areas with high levels of motor traffic, therefore, people living in crowded urban areas are frequently exposed to traffic-derived phenol vapor. The average (mean +/- SD) phenol concentration in urine among normal individuals living in urban areas is 7.4 +/- 2.2 mg/g of creatinine. Exposure of the skin to concentrated phenol solutions causes chemical burns which may be severe; in laboratories where it is used, it is usually recommended that polyethylene glycol solution is kept available for washing off splashes. Notwithstanding the effects of concentrated solutions, it is also used in cosmetic surgery as an exfoliant, to remove layers of dead skin (Wikipedia). In some bacteria phenol can be directly synthesized from tyrosine via the enzyme tyrosine phenol-lyase [EC:4.1.99.2]. It can be produced by Escherichia and Pseudomonas. Phenol has been identified as a uremic toxin according to the European Uremic Toxin Working Group (PMID: 22626821).
Phosphoenolpyruvate (PEP) is an important chemical compound in biochemistry. It has a high energy phosphate bond, and is involved in glycolysis and gluconeogenesis. In glycolysis, PEP is formed by the action of the enzyme enolase on 2-phosphoglycerate. Metabolism of PEP to pyruvate by pyruvate kinase (PK) generates 1 molecule of adenosine triphosphate (ATP) via substrate-level phosphorylation. ATP is one of the major currencies of chemical energy within cells. In gluconeogenesis, PEP is formed from the decarboxylation of oxaloacetate and hydrolysis of 1 guanosine triphosphate molecule. This reaction is catalyzed by the enzyme phosphoenolpyruvate carboxykinase (PEPCK). This reaction is a rate-limiting step in gluconeogenesis. (wikipedia).
O-Phosphoethanolamine, also known as PEA, phosphorylethanolamine, colamine phosphoric acid or ethanolamine O-phosphate, belongs to the class of organic compounds known as phosphoethanolamines. Phosphoethanolamines are compounds containing a phosphate linked to the second carbon of an ethanolamine. O-Phosphoethanolamine is used in the biosynthesis of two different types of phospholipids: glycerophospholipids and sphingolipids. O-Phosphoethanolamine exists in all living species, ranging from bacteria to plants to humans. Within humans, O-phosphoethanolamine participates in a number of enzymatic reactions. In particular, cytidine triphosphate and O-phosphoethanolamine can be converted into CDP-ethanolamine; which is mediated by the enzyme ethanolamine-phosphate cytidylyltransferase. In addition, O-phosphoethanolamine can be biosynthesized from ethanolamine; which is catalyzed by the enzyme choline/ethanolamine kinase. In humans, O-phosphoethanolamine is involved in phosphatidylcholine biosynthesis. O-phosphoethanolamine is also a product of the metabolism of sphingolipids. In particular, sphinglipids are metabolized in vivo to phosphorylethanolamine and a fatty aldehyde, generally palmitaldehyde. Both metabolites are ultimately converted to glycerophospholipids. The lipids are first phosphorylated by a kinase and then cleaved by the pyridoxal-dependent sphinganine-1-phosphate aldolase. Elevated urine levels of O-Phosphoethanolamine or PEA can be used to help in the diagnosis of Hypophosphatasia (HPP). Reference ranges for urinary PEA vary according to age and somewhat by diet, and follow a circadian rhythm. Outside of the human body, O-phosphoethanolamine has been detected, but not quantified in, several different foods, such as oxheart cabbages, anises, shiitakes, abalones, and teffs.
Picolinic acid is a metabolite of the tryptophan catabolism. Picolinic acid is produced under inflammatory conditions and a costimulus with interferon-gamma (IFNgamma) of macrophage (Mphi) effector functions, is a selective inducer of the Mphi inflammatory protein-1alpha (MIP-1alpha) and -1beta (MIPs), two chemokines/cytokines involved in the elicitation of the inflammatory reactions and in the development of the Th1 responses. IFNgamma and picolinic acid have reciprocal effects on the production of MIPs chemokines and the expression of their receptor. The concerted action of IFNgamma and picolinic acid on MIP-1alpha/beta chemokine/receptor system is likely to be of pathophysiological significance and to represent an important regulatory mechanism for leukocyte recruitment and distribution into damaged tissues during inflammatory responses. Picolinic acid has an effect on the production of L-arginine-derived reactive nitrogen intermediates in macrophages, by augmenting IFN-gamma-induced NO2- production, and acts synergistically with IFN-gamma in activating macrophages. Children with acrodermatitis enteropathica (AE) are treated with oral zinc dipicolinate (zinc-PA). The concentration of picolinic acid in the plasma of asymptomatic children with AE was significantly less than that of normal children. However, oral treatment with PA alone is ineffective. The results support the hypothesis that the genetic defect in AE is in the tryptophan pathway, although the role of PA in zinc metabolism remains to be defined. (PMID:15206716, 8473748, 1701787, 6694049).
PIP(16:0/22:2(13Z,16Z)) is a phosphatidylinositol phosphate. Phosphatidylinositol phosphates are acidic (anionic) phospholipids that consist of a phosphatidic acid backbone, linked via the phosphate group to a phosphorylated inositol (hexahydroxycyclohexane). Phosphatidylinositol phosphates are generated from phosphatidylinositols, which are phosphorylated by a number of different kinases that place the phosphate moiety on positions 4 and 5 of the inositol ring, although position 3 can also be phosphorylated. Phosphatidylinositols phosphates can have many different combinations of fatty acids of varying lengths and saturation attached at the C-1 and C-2 positions. Fatty acids containing 18 and 20 carbons are the most common. PIP(16:0/22:2(13Z,16Z)), in particular, consists of one chain of palmitic acid at the C-1 position and one chain of docosadienoic acid at the C-2 position. The palmitic acid moiety is derived from fish oils, milk fats, vegetable oils and animal fats, while the docosadienoic acid moiety is derived from animal fats. The most important phosphatidylinositol phosphate in both quantitative and biological terms is phosphatidylinositol 4-phosphate. Phosphatidylinositol and the phosphatidylinositol phosphates are the main source of diacylglycerols that serve as signaling molecules, via the action of phospholipase C enzymes. Phosphatidylinositols phosphates are usually present at low levels only in tissues, typically at about 1 to 3% of the concentration of phosphatidylinositol.
Pipecolic acid is a metabolite of lysine found in human physiological fluids such as urine, plasma and CSF. However, it is uncertain if pipecolic acid originates directly from food intake or from mammalian or intestinal bacterial enzyme metabolism. Recent studies suggest that plasma pipecolic acid, particularly the D-isomer, originates mainly from the catabolism of dietary lysine by intestinal bacteria rather than by direct food intake. In classic Zellweger syndrome (a cerebro-hepato-renal genetic disorder, OMIM 214100) pipecolic acid accumulate in the plasma of the patients. It is known that plasma pipecolic acid levels are also elevated in patients with chronic liver diseases. Pipecolic acid is moderately elevated in patients with pyridoxine-dependent seizures and might therefore be a possible biochemical marker for selecting candidates for pyridoxine therapy (Plecko et al 2000). Pipecolic acid was also elevated in CSF in these vitamin B6-responsive patients (PMID 12705501). Pipecolic acid is found to be associated with adrenoleukodystrophy, infantile Refsum disease, and peroxisomal biogenesis defect, which are also inborn errors of metabolism. Pipecolic acid is a biomarker for the consumption of dried and cooked beans.
Pipecolic acid is a metabolite of lysine found in human physiological fluids such as urine, plasma and CSF. However, it is uncertain if pipecolic acid originates directly from food intake or from mammalian or intestinal bacterial enzyme metabolism. Recent studies suggest that plasma pipecolic acid, particularly the D-isomer, originates mainly from the catabolism of dietary lysine by intestinal bacteria rather than by direct food intake. In classic Zellweger syndrome (a cerebro-hepato-renal genetic disorder, OMIM 214100) pipecolic acid accumulate in the plasma of the patients. It is known that plasma pipecolic acid levels are also elevated in patients with chronic liver diseases. Pipecolic acid is moderately elevated in patients with pyridoxine-dependent seizures and might therefore be a possible biochemical marker for selecting candidates for pyridoxine therapy (Plecko et al 2000). Pipecolic acid was also elevated in CSF in these vitamin B6-responsive patients (PMID 12705501). Pipecolic acid is found to be associated with adrenoleukodystrophy, infantile Refsum disease, and peroxisomal biogenesis defect, which are also inborn errors of metabolism. Pipecolic acid is a biomarker for the consumption of dried and cooked beans.
Pipecolic acid is a metabolite of lysine found in human physiological fluids such as urine, plasma and CSF. However, it is uncertain if pipecolic acid originates directly from food intake or from mammalian or intestinal bacterial enzyme metabolism. Recent studies suggest that plasma pipecolic acid, particularly the D-isomer, originates mainly from the catabolism of dietary lysine by intestinal bacteria rather than by direct food intake. In classic Zellweger syndrome (a cerebro-hepato-renal genetic disorder, OMIM 214100) pipecolic acid accumulate in the plasma of the patients. It is known that plasma pipecolic acid levels are also elevated in patients with chronic liver diseases. Pipecolic acid is moderately elevated in patients with pyridoxine-dependent seizures and might therefore be a possible biochemical marker for selecting candidates for pyridoxine therapy (Plecko et al 2000). Pipecolic acid was also elevated in CSF in these vitamin B6-responsive patients (PMID 12705501). Pipecolic acid is found to be associated with adrenoleukodystrophy, infantile Refsum disease, and peroxisomal biogenesis defect, which are also inborn errors of metabolism. Pipecolic acid is a biomarker for the consumption of dried and cooked beans.
Cysteinyl-Proline is a dipeptide composed of cysteine and proline. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. This dipeptide has not yet been identified in human tissues or biofluids and so it is classified as an 'Expected' metabolite.
Prolylhydroxyproline is a dipeptide. Prolylhydroxyproline is a marker of bone collagen degradation, showing high sensitivity for the diagnosis of osteoporosis. Prolylhydroxyproline has been suggested as a possible alternative to hydroxyproline determination in bone resorption studies. Prolylhydroxyproline is one of the iminodipeptides present in the urine of patients with prolidase deficiency. Prolidase (X-Pro dipeptidase EC 3.4.13.9) splits iminodipeptides containing C-terminal proline or hydroxyproline (X-Pro or X-Hyp) to X+Pro or X+Hyp. Prolidase deficiency is a rare autosomal recessive disease characterized by chronic ulcerative dermatitis and mental retardation. These patients excrete large amounts of iminodipeptides containing C-terminal proline in the urine due to hereditary prolidase deficiency (PMID: 12636053, 11863289, 2387877, 1874885, 9586797).
Prolylhydroxyproline is a dipeptide. Prolylhydroxyproline is a marker of bone collagen degradation, showing high sensitivity for the diagnosis of osteoporosis. Prolylhydroxyproline has been suggested as a possible alternative to hydroxyproline determination in bone resorption studies. Prolylhydroxyproline is one of the iminodipeptides present in the urine of patients with prolidase deficiency. Prolidase (X-Pro dipeptidase EC 3.4.13.9) splits iminodipeptides containing C-terminal proline or hydroxyproline (X-Pro or X-Hyp) to X+Pro or X+Hyp. Prolidase deficiency is a rare autosomal recessive disease characterized by chronic ulcerative dermatitis and mental retardation. These patients excrete large amounts of iminodipeptides containing C-terminal proline in the urine due to hereditary prolidase deficiency (PMID: 12636053, 11863289, 2387877, 1874885, 9586797).
Prolylhydroxyproline is a dipeptide. Prolylhydroxyproline is a marker of bone collagen degradation, showing high sensitivity for the diagnosis of osteoporosis. Prolylhydroxyproline has been suggested as a possible alternative to hydroxyproline determination in bone resorption studies. Prolylhydroxyproline is one of the iminodipeptides present in the urine of patients with prolidase deficiency. Prolidase (X-Pro dipeptidase EC 3.4.13.9) splits iminodipeptides containing C-terminal proline or hydroxyproline (X-Pro or X-Hyp) to X+Pro or X+Hyp. Prolidase deficiency is a rare autosomal recessive disease characterized by chronic ulcerative dermatitis and mental retardation. These patients excrete large amounts of iminodipeptides containing C-terminal proline in the urine due to hereditary prolidase deficiency (PMID: 12636053, 11863289, 2387877, 1874885, 9586797).
D-proline is an isomer of the naturally occurring amino acid, L-Proline. D-amino acids have been found in relatively high abundance in human plasma and saliva (PMID: 16480744). These amino acids may be of bacterial origin, but there is also evidence that they are endogenously produced through amino acid racemase activity (PMID: 1426150).
Proline betaine is an osmoprotective compound found in urine. It is thought to serve an osmoprotective role for the kidney. Proline betaine is a glycine betaine analogue found in many citrus foods. Elevated levels of proline betaine in human urine are found after the consumption of citrus fruits and juices (PMID: 18060588). Proline betaine is a biomarker for the consumption of citrus fruits.
Proline betaine is an osmoprotective compound found in urine. It is thought to serve an osmoprotective role for the kidney. Proline betaine is a glycine betaine analogue found in many citrus foods. Elevated levels of proline betaine in human urine are found after the consumption of citrus fruits and juices (PMID: 18060588). Proline betaine is a biomarker for the consumption of citrus fruits.
Prolylphenylalanine is a dipeptide composed of proline and phenylalanine. It is an incomplete breakdown product of protein digestion or protein catabolism. Some dipeptides are known to have physiological or cell-signaling effects although most are simply short-lived intermediates on their way to specific amino acid degradation pathways following further proteolysis. It is found in urine (PMID: 3782411).
Polyacrylic acid, sodium salt is used as a food additive [EAFUS] ("EAFUS: Everything Added to Food in the United States. [http://www.eafus.com/]")
Pseudouridine, also known as psi-uridine or 5-ribosyluracil, belongs to the class of organic compounds known as nucleoside and nucleotide analogues. These are analogues of nucleosides and nucleotides, such as phosphonated nucleosides, C-glycosylated nucleoside bases, analogues where the sugar unit is a pyranose, and carbocyclic nucleosides.  Pseudouridine specifically has its uracil attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond to the ribofuranose.  It is the most prevalent of the over one hundred different modified nucleosides found in RNA (PMID: 17113994).  Pseudouridine is a solid that is soluble in water.  Pseudouridine exists in all living species, ranging from bacteria to humans, and is in all classes of RNA except mRNA.  It is formed by enzymes called pseudouridine synthases, which post-transcriptionally isomerize specific uridine residues in RNA.
Pseudouridine, also known as psi-uridine or 5-ribosyluracil, belongs to the class of organic compounds known as nucleoside and nucleotide analogues. These are analogues of nucleosides and nucleotides, such as phosphonated nucleosides, C-glycosylated nucleoside bases, analogues where the sugar unit is a pyranose, and carbocyclic nucleosides.  Pseudouridine specifically has its uracil attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond to the ribofuranose.  It is the most prevalent of the over one hundred different modified nucleosides found in RNA (PMID: 17113994).  Pseudouridine is a solid that is soluble in water.  Pseudouridine exists in all living species, ranging from bacteria to humans, and is in all classes of RNA except mRNA.  It is formed by enzymes called pseudouridine synthases, which post-transcriptionally isomerize specific uridine residues in RNA.
Purine, also known as purine base or 1H-purine, belongs to the class of organic compounds known as purines and purine derivatives. These are aromatic heterocyclic compounds containing a purine moiety, which is formed a pyrimidine-ring ring fused to an imidazole ring. Two of the bases in nucleic acids, adenine and guanine, are purines. Purines from food (or from tissue turnover) are metabolised by several enzymes, including xanthine oxidase, into uric acid. Purine exists in all living species, ranging from bacteria to humans. High levels of uric acid can predispose to gout when the acid crystalises in joints; this phenomenon only happens in humans and some animal species (e.g. dogs) that lack an intrinsic uricase enzyme that can further degrade uric acid. In humans, purine is involved in thioguanine action pathway. Outside of the human body, purine is found, on average, in the highest concentration within cocoa beans. Purine has also been detected, but not quantified in several different foods, such as rapinis, plains prickly pears, blackcurrants, radish, and parsley. This could make purine a potential biomarker for the consumption of these foods. Purine is a heterocyclic aromatic organic compound, consisting of a pyrimidine ring fused to an imidazole ring.
Pyridoxal is a pyridinecarbaldehyde that is pyridine-4-carbaldehyde bearing methyl, hydroxy and hydroxymethyl substituents at positions 2, 3 and 5 respectively. Pyridoxal, also known as pyridoxaldehyde, belongs to the class of organic compounds known as pyridoxals and derivatives. Pyridoxals and derivatives are compounds containing a pyridoxal moiety, which consists of a pyridine ring substituted at positions 2, 3, 4, and 5 by a methyl group, a hydroxyl group, a carbaldehyde group, and a hydroxymethyl group, respectively. Pyridoxal is one form of vitamin B6. Pyridoxal exists in all living species, ranging from bacteria to humans. In humans, pyridoxal is involved in glycine and serine metabolism. Pyridoxal has been detected, but not quantified in several different foods, such as sourdoughs, lichee, arctic blackberries, watercress, and cottonseeds. Some medically relevant bacteria, such as those in the genera Granulicatella and Abiotrophia, require pyridoxal for growth. This nutritional requirement can lead to the culture phenomenon of satellite growth. In in vitro culture, these pyridoxal-dependent bacteria may only grow in areas surrounding colonies of bacteria from other genera ("satellitism") that are capable of producing pyridoxal. Pridoxal has a role as a cofactor, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite.
Pyridoxal is a pyridinecarbaldehyde that is pyridine-4-carbaldehyde bearing methyl, hydroxy and hydroxymethyl substituents at positions 2, 3 and 5 respectively. Pyridoxal, also known as pyridoxaldehyde, belongs to the class of organic compounds known as pyridoxals and derivatives. Pyridoxals and derivatives are compounds containing a pyridoxal moiety, which consists of a pyridine ring substituted at positions 2, 3, 4, and 5 by a methyl group, a hydroxyl group, a carbaldehyde group, and a hydroxymethyl group, respectively. Pyridoxal is one form of vitamin B6. Pyridoxal exists in all living species, ranging from bacteria to humans. In humans, pyridoxal is involved in glycine and serine metabolism. Pyridoxal has been detected, but not quantified in several different foods, such as sourdoughs, lichee, arctic blackberries, watercress, and cottonseeds. Some medically relevant bacteria, such as those in the genera Granulicatella and Abiotrophia, require pyridoxal for growth. This nutritional requirement can lead to the culture phenomenon of satellite growth. In in vitro culture, these pyridoxal-dependent bacteria may only grow in areas surrounding colonies of bacteria from other genera ("satellitism") that are capable of producing pyridoxal. Pridoxal has a role as a cofactor, a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite.
Pyridoxamine 5'-phosphate belongs to the class of organic compounds known as pyridoxamine 5'-phosphates. These are heterocyclic aromatic compounds containing a pyridoxamine that carries a phosphate group at the 5'-position. Vitamin B6 is a water-soluble compound that was discovered in 1930s during nutrition studies on rats. The vitamin was named pyridoxine to indicate its structural homology to pyridine. Later it was shown that vitamin B6 could exist in two other, slightly different, chemical forms, termed pyridoxal and pyridoxamine. All three forms of vitamin B6 are precursors of an activated compound known as pyridoxal 5-phosphate (PLP), which plays a vital role as the cofactor of a large number of essential enzymes in the human body. Vitamin B6 is a water-soluble vitamin. The three major forms of vitamin B6 are pyridoxine (also known as pyridoxol), pyridoxal, and pyridoxamine, which are all converted in the liver to pyridoxal 5-phosphate (PLP) a cofactor in many reactions of amino acid metabolism. PLP also is necessary for the enzymatic reaction governing the release of glucose from glycogen.
Pyridoxine, also known vitamin B6, is commonly found in food and is used as a dietary supplement. Pyridoxine is an essential nutrient, meaning the body cannot synthesize it, and it must be obtained from the diet. Sources in the diet include fruit, vegetables, and grain. Although pyridoxine and vitamin B6 are still frequently used as synonyms, especially by medical researchers, this practice is sometimes misleading (PMID: 2192605). Technically, pyridoxine is one of the compounds that can be called vitamin B6 or it is a member of the family of B6 vitamins. Healthy human blood levels of pyridoxine are 2.1 - 21.7 ng/mL. Pyridoxine is readily converted to pyridoxal phosphate which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids and aminolevulinic acid. Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. Therefore pyridoxine is required by the body to make amino acids, carbohydrates, and lipids. It is linked to cancer immunity and helps fight the formation of homocysteine. It has been suggested that pyridoxine might help children with learning difficulties, and may also prevent dandruff, eczema, and psoriasis. In addition, pyridoxine can help balance hormonal changes in women and aid in immune system. Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth (Wikipedia). Deficiency of pyridoxine, though rare because of widespread distribution in foods, leads to the development of peripheral neuritis in adults and affects the central nervous system in children (DOSE - 3rd edition). As a supplement pyridoxine is used to treat and prevent pyridoxine deficiency, sideroblastic anaemia, pyridoxine-dependent epilepsy, certain metabolic disorders, problems from isoniazid, and certain types of mushroom poisoning. Pyridoxine in combination with doxylamine is used as a treatment for morning sickness in pregnant women.
Pyridoxine, also known vitamin B6, is commonly found in food and is used as a dietary supplement. Pyridoxine is an essential nutrient, meaning the body cannot synthesize it, and it must be obtained from the diet. Sources in the diet include fruit, vegetables, and grain. Although pyridoxine and vitamin B6 are still frequently used as synonyms, especially by medical researchers, this practice is sometimes misleading (PMID: 2192605). Technically, pyridoxine is one of the compounds that can be called vitamin B6 or it is a member of the family of B6 vitamins. Healthy human blood levels of pyridoxine are 2.1 - 21.7 ng/mL. Pyridoxine is readily converted to pyridoxal phosphate which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids and aminolevulinic acid. Pyridoxine assists in the balancing of sodium and potassium as well as promoting red blood cell production. Therefore pyridoxine is required by the body to make amino acids, carbohydrates, and lipids. It is linked to cancer immunity and helps fight the formation of homocysteine. It has been suggested that pyridoxine might help children with learning difficulties, and may also prevent dandruff, eczema, and psoriasis. In addition, pyridoxine can help balance hormonal changes in women and aid in immune system. Lack of pyridoxine may cause anemia, nerve damage, seizures, skin problems, and sores in the mouth (Wikipedia). Deficiency of pyridoxine, though rare because of widespread distribution in foods, leads to the development of peripheral neuritis in adults and affects the central nervous system in children (DOSE - 3rd edition). As a supplement pyridoxine is used to treat and prevent pyridoxine deficiency, sideroblastic anaemia, pyridoxine-dependent epilepsy, certain metabolic disorders, problems from isoniazid, and certain types of mushroom poisoning. Pyridoxine in combination with doxylamine is used as a treatment for morning sickness in pregnant women.
Pyridoxine is one of the compounds that can be called vitamin B6, along with pyridoxal and pyridoxamine. It differs from pyridoxamine by the substituent at the '4' position. It is often used as 'pyridoxine hydrochloride'.
Pyrimidine is a heterocyclic aromatic organic compound similar to benzene and pyridine, containing two nitrogen atoms at positions 1 and 3 of the six-member ring. Pyrimidines are heterocyclic, six-membered, nitrogen-containing carbon ring structures, with uracil, cytosine and thymine being the basal structures of ribose-containing nucleosides (uridine, cytidine and thymidine respectively), or deoxyribose-containing deoxynucleosides, and their corresponding ribonucleotides or deoxyribonucleotides. Pyrimidines serve essential functions in human metabolism as ribonucleotide bases in RNA (uracil and cytosine), and as deoxyribonucleotide bases in DNA (cytosine and thymine), and are linked by phosphodiester bridges to purine nucleotides in double-stranded DNA, in both the nucleus and the mitochondria. Pyrimidine activated sugars are also involved in polysaccharide and phospholipid synthesis, glucuronidation in detoxification processes, glycosylation of proteins and lipids and in the recently identified novel endothelium-derived vasoactive dinucleotides. Pyrimidines are synthesized de novo from simple precursors. Synthesis occurs in six steps, with cellular compartmentalization of specific steps in the cytosol or mitochondria, enabling changes in metabolic rate with need. Pyrimidine synthesis differs from purine synthesis, in that the single pyrimidine ring is assembled first and is then linked to ribose phosphate to form UMP. The enzymes that catalyse UMP synthesis, CAD [carbamoylphosphate synthetase II (CPSII), aspartate transcarbamoylase (ATCasea) and dihydroorotase (DHOase)], dihydroorotate dehydrogenase (DHODH) and uridine monophosphate synthase (UMPS), are encoded by only three genes - CAD, DHODH and UMPS (chromosomal locations 2p21, 16q22 and 3q13, respectively). (PMID:16098809).
Pyrrole-2-carboxylic acid was synthesized over a century ago, but its history as a compound of biological origin is rather recent. It was first identified as a degradation product of sialic acids, then as a derivative of the oxidation of the D-hydroxyproline isomers by mammalian D-amino acid oxidase. The latter relationship results from the lability of the direct oxidation product, A'-pyrroline-4-hydroxy-2-carboxylic acid, which loses water spontaneously to form the pyrrole. A similar reaction is catalyzed by the more specific allohydroxy-D-proline oxidase of Pseudomonas. In whole animal observations, pyrrole-2-carboxylate (PCA) ' was identified in rat or human urine after administration of the D-isomers of hydroxyproline, a finding ascribable to the action of D-amino acid oxidase. (PMID:4430715). Urinary excretion of N-(pyrrole-2-carboxyl) glycine has been reported in a 5-year-old affected with type II hyperprolinemia; The child has mild developmental delay, recurrent seizures of the grand mal type and EEG alterations. The urinary excretion of the conjugate is stressed, since it appears that only one previous report in the literature described this compound in the urine of two patients affected by this disturbance (PMID 2383933).
Pyruvaldehyde is an organic compound used often as a reagent in organic synthesis, as a flavoring agent, and in tanning. It has been demonstrated as an intermediate in the metabolism of acetone and its derivatives in isolated cell preparations, in various culture media, and in vivo in certain animals.
Synthetic dimer was found to react rapidly with pyruvate to form the expected oxime. 1H NMR spectrum of the purified oxime is superimposable with that arising when the dimer and pyruvate are mixed and the spectrum taken immediately thereafter. Then the mass spectrum of the reaction product of cycloserine dimer and methylpyruvate is totally consistent with the formation of a stable oxime derivative. Furthermore, when cycloserine is incubated with pyruvate the oxime derived from the dimer is found.(PMID: 2495795).
Pyruvic acid or pyruvate is a simple alpha-keto acid. It is a three-carbon molecule containing a carboxylic acid group and a ketone functional group. Pyruvate is the simplest alpha-keto acid and according to official nomenclature by IUPAC, it is called alpha-keto propanoic acid. Like other keto acids, pyruvic acid can tautomerize from its ketone form to its enol form, containing a double bond and an alcohol. Pyruvate is found in all living organisms ranging from bacteria to plants to humans. It is intermediate compound in the metabolism of carbohydrates, proteins, and fats. Pyruvate is a key intermediate in several metabolic pathways throughout the cell. In particular, pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA. Pyruvic acid supplies energy to cells through the citric acid cycle (TCA or Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking (lactic acid). In glycolysis, phosphoenolpyruvate (PEP) is converted to pyruvate by pyruvate kinase. This reaction is strongly exergonic and irreversible. In gluconeogenesis, it takes two enzymes, pyruvate carboxylase and PEP carboxykinase, to catalyze the reverse transformation of pyruvate to PEP. Pyruvic acid is also a metabolite of Corynebacterium (PMID: 27872963).
Pyruvic acid or pyruvate is a simple alpha-keto acid. It is a three-carbon molecule containing a carboxylic acid group and a ketone functional group. Pyruvate is the simplest alpha-keto acid and according to official nomenclature by IUPAC, it is called alpha-keto propanoic acid. Like other keto acids, pyruvic acid can tautomerize from its ketone form to its enol form, containing a double bond and an alcohol. Pyruvate is found in all living organisms ranging from bacteria to plants to humans. It is intermediate compound in the metabolism of carbohydrates, proteins, and fats. Pyruvate is a key intermediate in several metabolic pathways throughout the cell. In particular, pyruvic acid can be made from glucose through glycolysis, converted back to carbohydrates (such as glucose) via gluconeogenesis, or to fatty acids through a reaction with acetyl-CoA. Pyruvic acid supplies energy to cells through the citric acid cycle (TCA or Krebs cycle) when oxygen is present (aerobic respiration), and alternatively ferments to produce lactate when oxygen is lacking (lactic acid). In glycolysis, phosphoenolpyruvate (PEP) is converted to pyruvate by pyruvate kinase. This reaction is strongly exergonic and irreversible. In gluconeogenesis, it takes two enzymes, pyruvate carboxylase and PEP carboxykinase, to catalyze the reverse transformation of pyruvate to PEP. Pyruvic acid is also a metabolite of Corynebacterium (PMID: 27872963).
Quinic acid, also known as quinate, belongs to the class of organic compounds known as quinic acids and derivatives. Quinic acids and derivatives are compounds containing a quinic acid moiety (or a derivative thereof), which is a cyclitol made up of a cyclohexane ring that bears four hydroxyl groups at positions 1,3, 4, and 5, as well as a carboxylic acid at position 1. Quinic acid is a sugar acid. It is also a cyclitol, or cyclic polyol. More specifically, quinic acid is a crystalline acid obtained from cinchona bark, coffee beans, tobacco leaves, carrot leaves, apples, peaches, pears, plums, vegetables, etc. Quinic acid can also be made synthetically by hydrolysis of chlorogenic acid. Quinic acid is implicated in the perceived acidity of coffee.
Quinic acid, also known as quinate, belongs to the class of organic compounds known as quinic acids and derivatives. Quinic acids and derivatives are compounds containing a quinic acid moiety (or a derivative thereof), which is a cyclitol made up of a cyclohexane ring that bears four hydroxyl groups at positions 1,3, 4, and 5, as well as a carboxylic acid at position 1. Quinic acid is a sugar acid. It is also a cyclitol, or cyclic polyol. More specifically, quinic acid is a crystalline acid obtained from cinchona bark, coffee beans, tobacco leaves, carrot leaves, apples, peaches, pears, plums, vegetables, etc. Quinic acid can also be made synthetically by hydrolysis of chlorogenic acid. Quinic acid is implicated in the perceived acidity of coffee.
Resveratrol is a polyphenolic phytoalexin. It is also classified as a stilbenoid, a derivate of stilbene, and is produced in plants with the help of the enzyme stilbene synthase. The levels of resveratrol found in food vary greatly. Red wine contains between 0.2 and 5.8 mg/L depending on the grape variety, while white wine has much less. The reason for this difference is that red wine is fermented with grape skins, allowing the wine to absorb the resveratrol, whereas white wine is fermented after the skin has been removed. Resveratrol is also sold as a nutritional supplement. A number of beneficial health effects, such as anti-cancer, antiviral, neuroprotective, anti-aging, anti-inflammatory, and life-prolonging effects have been reported for resveratrol. The fact that resveratrol is found in the skin of red grapes and as a constituent of red wine may explain the "French paradox". This paradox is based on the observation that the incidence of coronary heart disease is relatively low in southern France despite high dietary intake of saturated fats. Resveratrol is thought to achieve these cardioprotective effects by a number of different routes: (1) inhibition of vascular cell adhesion molecule expression; (2) inhibition of vascular smooth muscle cell proliferation; (3) stimulation of endothelial nitric oxide synthase (eNOS) activity; (4) inhibition of platelet aggregation; and (5) inhibition of LDL peroxidation (PMID: 17875315, 14676260, 9678525). Resveratrol is a biomarker for the consumption of grapes and raisins.
S-Adenosylmethionine (CAS: 29908-03-0), also known as SAM or AdoMet, is a physiologic methyl radical donor involved in enzymatic transmethylation reactions and present in all living organisms. It possesses anti-inflammatory activity and has been used in the treatment of chronic liver disease (From Merck, 11th ed). S-Adenosylmethionine is a natural substance present in the cells of the body. It plays a crucial biochemical role by donating a one-carbon methyl group in a process called transmethylation. S-Adenosylmethionine, formed from the reaction of L-methionine and adenosine triphosphate catalyzed by the enzyme S-adenosylmethionine synthetase, is the methyl-group donor in the biosynthesis of both DNA and RNA nucleic acids, phospholipids, proteins, epinephrine, melatonin, creatine, and other molecules.
(S)C(S)S-S-Methylcysteine sulfoxide is found in brassicas. (S)C(S)S-S-Methylcysteine sulfoxide is a constituent of onion (Allium cepa), other Allium species and Brassica species. Potential nutriceutical
Salicylamide is the common name for the substance o-hydroxybenzamide, or amide of salicyl. Salicylamide is a non-prescription drug with analgesic and antipyretic properties. Its medicinal uses are similar to those of aspirin. Salicylamide is used in combination with both aspirin and caffeine in the over-the-counter pain remedies
Salicylic acid is a monohydroxybenzoic acid that is benzoic acid with a hydroxy group at the ortho position. It is obtained from the bark of the white willow and wintergreen leaves. It has a role as an antiinfective agent, an antifungal agent, a keratolytic drug, an EC 1.11.1.11 (L-ascorbate peroxidase) inhibitor, a plant metabolite, an algal metabolite and a plant hormone. It is a conjugate acid of a salicylate. It is a colorless solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone. The name is from Latin salix for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates. Salicylic acid modulates COX1 enzymatic activity to decrease the formation of pro-inflammatory prostaglandins. Salicylate may competitively inhibit prostaglandin formation. Salicylate's antirheumatic (nonsteroidal anti-inflammatory) actions are a result of its analgesic and anti-inflammatory mechanisms. Salicylic acid works by causing the cells of the epidermis to slough off more readily, preventing pores from clogging up, and allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) competitively with nicotinamide adenosine dinucleotide and noncompetitively with UDPG. It also competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor. The wound-healing retardation action of salicylates is probably due mainly to its inhibitory action on mucopolysaccharide synthesis. Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana, it can be synthesized via a phenylalanine-independent pathway.
Salicylic acid is a monohydroxybenzoic acid that is benzoic acid with a hydroxy group at the ortho position. It is obtained from the bark of the white willow and wintergreen leaves. It has a role as an antiinfective agent, an antifungal agent, a keratolytic drug, an EC 1.11.1.11 (L-ascorbate peroxidase) inhibitor, a plant metabolite, an algal metabolite and a plant hormone. It is a conjugate acid of a salicylate. It is a colorless solid, it is a precursor to and a metabolite of aspirin (acetylsalicylic acid). It is a plant hormone. The name is from Latin salix for willow tree. It is an ingredient in some anti-acne products. Salts and esters of salicylic acid are known as salicylates. Salicylic acid modulates COX1 enzymatic activity to decrease the formation of pro-inflammatory prostaglandins. Salicylate may competitively inhibit prostaglandin formation. Salicylate's antirheumatic (nonsteroidal anti-inflammatory) actions are a result of its analgesic and anti-inflammatory mechanisms. Salicylic acid works by causing the cells of the epidermis to slough off more readily, preventing pores from clogging up, and allowing room for new cell growth. Salicylic acid inhibits the oxidation of uridine-5-diphosphoglucose (UDPG) competitively with nicotinamide adenosine dinucleotide and noncompetitively with UDPG. It also competitively inhibits the transferring of glucuronyl group of uridine-5-phosphoglucuronic acid to the phenolic acceptor. The wound-healing retardation action of salicylates is probably due mainly to its inhibitory action on mucopolysaccharide synthesis. Salicylic acid is biosynthesized from the amino acid phenylalanine. In Arabidopsis thaliana, it can be synthesized via a phenylalanine-independent pathway.
Sarcosine is the N-methyl derivative of glycine. Sarcosine is metabolized to glycine by the enzyme sarcosine dehydrogenase, while glycine-N-methyl transferase generates sarcosine from glycine. Sarcosine is a natural amino acid found in muscles and other body tissues. In the laboratory it may be synthesized from chloroacetic acid and methylamine. Sarcosine is naturally found in the metabolism of choline to glycine. Sarcosine is sweet to the taste and dissolves in water. It is used in manufacturing biodegradable surfactants and toothpastes as well as in other applications. Sarcosine is ubiquitous in biological materials and is present in such foods as egg yolks, turkey, ham, vegetables, legumes, etc. Sarcosine is formed from dietary intake of choline and from the metabolism of methionine, and is rapidly degraded to glycine. Sarcosine has no known toxicity, as evidenced by the lack of phenotypic manifestations of sarcosinemia, an inborn error of sarcosine metabolism. Sarcosinemia can result from severe folate deficiency because of the folate requirement for the conversion of sarcosine to glycine (Wikipedia). Sarcosine has recently been identified as a biomarker for invasive prostate cancer. It was found to be greatly increased during prostate cancer progression to metastasis and could be detected in urine. Sarcosine levels were also increased in invasive prostate cancer cell lines relative to benign prostate epithelial cells (PMID: 19212411).
Selenomethionine (CAS: 1464-42-2) is an amino acid containing selenium that cannot be synthesized by higher animals but can be obtained from plant material. Selenomethionine is the major seleno-compound in cereal grains (wheat grain, maize, and rice), soybeans, and enriched yeast. Seleno-compounds present in plants may have a profound effect on the health of animals and human subjects. It is now known that the total Se content cannot be used as an indication of its efficacy, but knowledge of individual selenocompounds is necessary to fully assess the significance. Thus, speciation of the seleno-compounds has moved to the forefront. Since animals and man are dependent upon plants for their nutritional requirements, this makes the types of seleno-compounds in plants even more critical. Se enters the food chain through incorporation into plant proteins, mostly as selenocysteine and selenomethionine at normal Se levels. There are two possible pathways for the catabolism of selenomethionine. One is the transsulfuration pathway via selenocystathionine to produce selenocysteine, which in turn is degraded into H2Se by the enzyme beta-lyase. The other pathway is the transamination-decarboxylation pathway. It was estimated that 90% of methionine is metabolized through this pathway and thus could be also the major route for selenomethionine catabolism (PMID:14748935).
Sphingomyelin (d18:0/16:1(9Z)) or SM(d18:0/16:1(9Z)) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath which surrounds some nerve cell axons. It usually consists of phosphorylcholine and ceramide. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SPH has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2 - an enzyme that breaks down sphingomyelin into ceramide has been found to localise exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme Sphingomyelinase, which causes the accumulation of Sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.
Sphingomyelin (d18:0/18:1(11Z)) or SM(d18:0/18:1(11Z)) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath which surrounds some nerve cell axons. It usually consists of phosphorylcholine and ceramide. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SPH has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2 - an enzyme that breaks down sphingomyelin into ceramide has been found to localise exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme Sphingomyelinase, which causes the accumulation of Sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.
Sphingomyelin (d18:1/22:1(13Z)) or SM(d18:1/22:1(13Z)) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath which surrounds some nerve cell axons. It usually consists of phosphorylcholine and ceramide. SM(d18:1/22:1(13Z)) consists of a sphingosine backbone and an erucic acid chain. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SM has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition, it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2, an enzyme that breaks down sphingomyelin into ceramide, has been found to localize exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme sphingomyelinase, which causes the accumulation of sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.
Sphingomyelin (d18:1/24:1(15Z)) or SM(d18:1/24:1(15Z)) is a type of sphingolipid found in animal cell membranes, especially in the membranous myelin sheath which surrounds some nerve cell axons. It usually consists of phosphorylcholine and ceramide. SM(d18:1/24:1(15Z)) consists of a sphingosine backbone and a nervonic acid chain. In humans, sphingomyelin is the only membrane phospholipid not derived from glycerol. Like all sphingolipids, SM has a ceramide core (sphingosine bonded to a fatty acid via an amide linkage). In addition, it contains one polar head group, which is either phosphocholine or phosphoethanolamine. The plasma membrane of cells is highly enriched in sphingomyelin and is considered largely to be found in the exoplasmic leaflet of the cell membrane. However, there is some evidence that there may also be a sphingomyelin pool in the inner leaflet of the membrane. Moreover, neutral sphingomyelinase-2, an enzyme that breaks down sphingomyelin into ceramide, has been found to localize exclusively to the inner leaflet further suggesting that there may be sphingomyelin present there. Sphingomyelin can accumulate in a rare hereditary disease called Niemann-Pick Disease, types A and B. Niemann-Pick disease is a genetically-inherited disease caused by a deficiency in the enzyme sphingomyelinase, which causes the accumulation of sphingomyelin in spleen, liver, lungs, bone marrow, and the brain, causing irreversible neurological damage. SMs play a role in signal transduction. Sphingomyelins are synthesized by the transfer of phosphorylcholine from phosphatidylcholine to a ceramide in a reaction catalyzed by sphingomyelin synthase.
Glycerylphosphorylethanolamine is a membrane breakdown product resulting from the cleavage of the lipid group from glycerophosphoethanlomine fatty acids (i.e. phosphatidylethanolamine). It acts as a growth stimulant for hepatocytes.
Glycerylphosphorylethanolamine is a membrane breakdown product resulting from the cleavage of the lipid group from glycerophosphoethanlomine fatty acids (i.e. phosphatidylethanolamine). It acts as a growth stimulant for hepatocytes.
Glycerol 3-phosphate is a chemical intermediate in the glycolysis metabolic pathway. It is commonly confused with the similarly named glycerate 3-phosphate or glyceraldehyde 3-phosphate. Glycerol 3-phosphate is produced from glycerol, the triose sugar backbone of triglycerides and glycerophospholipids, by the enzyme glycerol kinase. Glycerol 3-phospate may then be converted by dehydrogenation to dihydroxyacetone phosphate (DHAP) by the enzyme glycerol-3-phosphate dehydrogenase. DHAP can then be rearranged into glyceraldehyde 3-phosphate (GA3P) by triose phosphate isomerase (TIM), and feed into glycolysis. The glycerol 3-phosphate shuttle is used to rapidly regenerate NAD+ in the brain and skeletal muscle cells of mammals (wikipedia).
Sorbitol is a polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications. Ascorbic acid fermentation; in solution form for moisture-conditioning of cosmetic creams and lotions, toothpaste, tobacco, gelatin; bodying agent for paper, textiles, and liquid pharmaceuticals; softener for candy; sugar crystallization inhibitor; surfactants; urethane resins and rigid foams; plasticizer, stabilizer for vinyl resins; food additive (sweetener, humectant, emulsifier, thickener, anticaking agent); dietary supplement. (Hawley's Condensed Chemical Dictionary) Biological Source: Occurs widely in plants ranging from algae to the higher orders. Fruits of the plant family Rosaceae, which include apples, pears, cherries, apricots, contain appreciable amounts. Rich sources are the fruits of the Sorbus and Crataegus species Use/Importance: Used for manufacturing of sorbose, propylene glycol, ascorbic acid, resins, plasticizers and as antifreeze mixtures with glycerol or glycol. Tablet diluent, sweetening agent and humectant, other food uses. Sorbitol is used in photometric determination of Ru(VI) and Ru(VIII); in acid-base titration of borate (Dictionary of Organic Compounds).
Sphinganine belongs to the class of organic compounds known as 1,2-aminoalcohols. These are organic compounds containing an alkyl chain with an amine group bound to the C1 atom and an alcohol group bound to the C2 atom. Thus, sphinganine is considered to be a sphingoid base lipid molecule. Sphinganine is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Sphinganine exists in all living species, ranging from bacteria to humans. Within humans, sphinganine participates in a number of enzymatic reactions. In particular, sphinganine can be converted into 3-dehydrosphinganine through its interaction with the enzyme 3-ketodihydrosphingosine reductase. In addition, sphinganine can be converted into sphinganine 1-phosphate; which is catalyzed by the enzyme sphingosine kinase 2. Outside of the human body, sphinganine has been detected, but not quantified in, several different foods, such as Mexican oregano, jostaberries, winter squash, angelica, and epazotes. This could make sphinganine a potential biomarker for the consumption of these foods. Sphinganine blocks postlysosomal cholesterol transport by inhibiting low-density lipoprotein-induced esterification of cholesterol and causing unesterified cholesterol to accumulate in perinuclear vesicles. It has been suggested that endogenous sphinganine may inhibit cholesterol transport in Niemann-Pick Type C (NPC) disease (PMID: 1817037).
Sphinganine belongs to the class of organic compounds known as 1,2-aminoalcohols. These are organic compounds containing an alkyl chain with an amine group bound to the C1 atom and an alcohol group bound to the C2 atom. Thus, sphinganine is considered to be a sphingoid base lipid molecule. Sphinganine is a very hydrophobic molecule, practically insoluble (in water), and relatively neutral. Sphinganine exists in all living species, ranging from bacteria to humans. Within humans, sphinganine participates in a number of enzymatic reactions. In particular, sphinganine can be converted into 3-dehydrosphinganine through its interaction with the enzyme 3-ketodihydrosphingosine reductase. In addition, sphinganine can be converted into sphinganine 1-phosphate; which is catalyzed by the enzyme sphingosine kinase 2. Outside of the human body, sphinganine has been detected, but not quantified in, several different foods, such as Mexican oregano, jostaberries, winter squash, angelica, and epazotes. This could make sphinganine a potential biomarker for the consumption of these foods. Sphinganine blocks postlysosomal cholesterol transport by inhibiting low-density lipoprotein-induced esterification of cholesterol and causing unesterified cholesterol to accumulate in perinuclear vesicles. It has been suggested that endogenous sphinganine may inhibit cholesterol transport in Niemann-Pick Type C (NPC) disease (PMID: 1817037).
Sucrose is a nonreducing disaccharide composed of glucose and fructose linked via their anomeric carbons. It is obtained commercially from sugarcane (Saccharum officinarum), sugar beet (Beta vulgaris), and other plants and used extensively as a food and a sweetener. Sucrose is derived by crushing and extracting sugarcane with water or by extracting sugar beet with water, evaporating, and purifying with lime, carbon, and various liquids. Sucrose is also obtainable from sorghum. Sucrose occurs in low percentages in honey and maple syrup. Sucrose is used as a sweetener in foods and soft drinks, in the manufacture of syrups, in invert sugar, confectionery, preserves and jams, demulcent, pharmaceutical products, and caramel. Sucrose is also a chemical intermediate for detergents, emulsifying agents, and other sucrose derivatives. Sucrose is widespread in the seeds, leaves, fruits, flowers, and roots of plants, where it functions as an energy store for metabolism and as a carbon source for biosynthesis. The annual world production of sucrose is in excess of 90 million tons mainly from the juice of sugar cane (20%) and sugar beet (17%). In addition to its use as a sweetener, sucrose is used in food products as a preservative, antioxidant, moisture control agent, stabilizer, and thickening agent. BioTransformer predicts that sucrose is a product of 6-O-sinapoyl sucrose metabolism via a hydrolysis-of-carboxylic-acid-ester-pattern1 reaction occurring in human gut microbiota and catalyzed by the liver carboxylesterase 1 (P23141) enzyme (PMID: 30612223).
Sulfolithocholylglycine is an acyl glycine and a bile acid-glycine conjugate. It is a secondary bile acid produced by the action of enzymes existing in the microbial flora of the colonic environment. In hepatocytes, both primary and secondary bile acids undergo amino acid conjugation at the C-24 carboxylic acid on the side chain, and almost all bile acids in the bile duct, therefore, exist in a glycine conjugated form (PMID: 16949895). Sulfolithocholylglycine is a sulfated bile acid which has a greater renal clearance rate than lithocholylglycine.
The sulfate ion is a polyatomic anion with the empirical formula SO42- and a molecular mass of 96.06 daltons; it consists of one central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The sulfate ion carries a negative two charge and is the conjugate base of the hydrogen sulfate ion, HSO4-, which is the conjugate base of H2SO4, sulfuric acid. In inorganic chemistry, a sulfate (IUPAC-recommended spelling; also sulphate in British English) is a salt of sulfuric acid. Sulfate aerosols can act as cloud condensation nuclei and this leads to greater numbers of smaller droplets of water. Lots of smaller droplets can diffuse light more efficiently than just a few larger droplets.
Symmetric dimethylarginine, also known as N,n'-dimethylarginine or SDMA, is a L-arginine derivative having two methyl groups at the N(omega)- and N'(omega)-positions It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor. It is a member of guanidines, a non-proteinogenic L-alpha-amino acid, a L-arginine derivative and a dimethylarginine. It is a tautomer of a N(omega),N'(omega)-dimethyl-L-arginine zwitterion. It belongs to the class of organic compounds known as arginine and derivatives. Arginine and derivatives are compounds containing arginine or a derivative thereof resulting from reaction of arginine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. Symmetric dimethylarginine is a drug. Outside of the human body, symmetric dimethylarginine has been detected, but not quantified in pulses. Symmetric dimethylarginine (SDMA) is an endogenously produced inhibitor of nitric oxide synthase (EC-Number 1.14.13.39). However, elevated levels of Symmetric dimethylarginine occur in patients with vascular disease, especially suffering end-stage renal disease.
Symmetric dimethylarginine, also known as N,n'-dimethylarginine or SDMA, is a L-arginine derivative having two methyl groups at the N(omega)- and N'(omega)-positions It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor. It is a member of guanidines, a non-proteinogenic L-alpha-amino acid, a L-arginine derivative and a dimethylarginine. It is a tautomer of a N(omega),N'(omega)-dimethyl-L-arginine zwitterion. It belongs to the class of organic compounds known as arginine and derivatives. Arginine and derivatives are compounds containing arginine or a derivative thereof resulting from reaction of arginine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. Symmetric dimethylarginine is a drug. Outside of the human body, symmetric dimethylarginine has been detected, but not quantified in pulses. Symmetric dimethylarginine (SDMA) is an endogenously produced inhibitor of nitric oxide synthase (EC-Number 1.14.13.39). However, elevated levels of Symmetric dimethylarginine occur in patients with vascular disease, especially suffering end-stage renal disease.
Symmetric dimethylarginine, also known as N,n'-dimethylarginine or SDMA, is a L-arginine derivative having two methyl groups at the N(omega)- and N'(omega)-positions It has a role as an EC 1.14.13.39 (nitric oxide synthase) inhibitor. It is a member of guanidines, a non-proteinogenic L-alpha-amino acid, a L-arginine derivative and a dimethylarginine. It is a tautomer of a N(omega),N'(omega)-dimethyl-L-arginine zwitterion. It belongs to the class of organic compounds known as arginine and derivatives. Arginine and derivatives are compounds containing arginine or a derivative thereof resulting from reaction of arginine at the amino group or the carboxy group, or from the replacement of any hydrogen of glycine by a heteroatom. Symmetric dimethylarginine is a drug. Outside of the human body, symmetric dimethylarginine has been detected, but not quantified in pulses. Symmetric dimethylarginine (SDMA) is an endogenously produced inhibitor of nitric oxide synthase (EC-Number 1.14.13.39). However, elevated levels of Symmetric dimethylarginine occur in patients with vascular disease, especially suffering end-stage renal disease.
Threonic acid, also known as threonate, belongs to the class of organic compounds known as sugar acids and derivatives. Sugar acids and derivatives are compounds containing a saccharide unit which bears a carboxylic acid group. Threonic acid is a sugar acid derived from threose. The L-isomer is a metabolite of ascorbic acid (vitamin C). One study suggested that because L-threonate inhibits DKK1 expression in vitro, it may have potential in the treatment of androgenic alopecia (PMID:21034532). Threonic acid is probably derived from glycated proteins or from degradation of ascorbic acid. It is a normal component in aqueous humour and blood (PMID:10420182). Threonic acid is a substrate of L-threonate 3-dehydrogenase (EC 1.1.1.129) in the ascorbate and aldarate metabolism pathway (KEGG). It has been found to be a microbial metabolite (PMID:20615997).
5-Thymidylic acid (conjugate base thymidylate), also known as thymidine monophosphate (TMP), deoxythymidine monophosphate (dTMP), or deoxythymidylic acid (conjugate base deoxythymidylate), is a nucleotide that is used as a monomer in DNA. It is an ester of phosphoric acid with the nucleoside thymidine. dTMP consists of a phosphate group, the pentose sugar deoxyribose, and the nucleobase thymine. Unlike the other deoxyribonucleotides, thymidine monophosphate often does not contain the "deoxy" prefix in its name; nevertheless, its symbol often includes a "d" ("dTMP"). 5-Thymidylic acid belongs to the class of organic compounds known as pyrimidine 2'-deoxyribonucleoside monophosphates. These are pyrimidine nucleotides with a monophosphate group linked to the ribose moiety lacking a hydroxyl group at position 2. The neutral species of 5-Thymidylic acid (2'-deoxythymidine 5'-monophosphate). 5-Thymidylic acid exists in all living species, ranging from bacteria to humans. Within humans, 5-thymidylic acid participates in a number of enzymatic reactions. In particular, 5-thymidylic acid and dihydrofolic acid can be biosynthesized from dUMP and 5,10-methylene-THF by the enzyme thymidylate synthase. In addition, 5-thymidylic acid can be converted into dTDP; which is catalyzed by the enzyme thymidylate synthase. In humans, 5-thymidylic acid is involved in pyrimidine metabolism. Outside of the human body, 5-Thymidylic acid has been detected, but not quantified in several different foods, such as common buckwheats, corn salad, garden cress, squashberries, and star fruits.
L-Targinine is found in pulses. L-Targinine is isolated from broad bean seed L-Targinine has been identified in the human placenta (PMID: 32033212).
4-Hydroxyproline (hydroxyproline or Hyp) is a major component of the protein collagen. Hydroxyproline is produced by hydroxylation of the amino acid proline and is, therefore, a post-translationally modified, non-essential amino acid. Hydroxyproline and proline play key roles in collagen stability. In particular, they permit the sharp twisting of the collagen helix. Hydroxyproline is found in few proteins other than collagen. The only other mammalian protein which includes hydroxyproline is elastin. For this reason, hydroxyproline content has been used as an indicator to determine collagen and/or gelatin amount in tissue or biological samples. Increased serum and urine levels of hydroxyproline have been found in Paget's disease (PMID: 436278). Hydroxyproline (Hyp) content in biological fluids is used as a parameter of collagen catabolism, especially bone resorption or tissue degradation. Bedridden and elderly individuals show significantly elevated serum levels of hydroxyproline in comparison to normal, active individuals (PMID: 10706420). Elevated levels of urinary hydroxyproline are also indicative of muscle damage (PMID: 21988268). Increased reactive oxygen species (ROS) are also known to accelerate collagen degradation. Hydroxyproline levels increase in cases of depression and stress (PMID: 21483218). 4-Hydroxyproline is found to be associated with Alzheimer's disease, and also hydroxyprolinemia and iminoglycinuria which are both inborn errors of metabolism. 4-Hydroxyproline is also involved in metabolic disorders such as hyperprolinemia type I, hyperornithinemia with gyrate atrophy (HOGA), L-arginine:glycine amidinotransferase deficiency, creatine deficiency, and guanidinoacetate methyltransferase deficiency. A deficiency in ascorbic acid can result in impaired hydroxyproline formation (PubChem). trans-4-Hydroxy-L-proline is a biomarker for the consumption of processed meat.
Trigonelline, also known as caffearin or gynesine, belongs to the class of organic compounds known as alkaloids and derivatives. These are naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids. In addition to carbon, hydrogen and nitrogen, alkaloids may also contain oxygen, sulfur and more rarely other elements such as chlorine, bromine, and phosphorus. It is also found in coffee, where it may help to prevent dental caries by preventing the bacteria Streptococcus mutans from adhering to teeth. Trigonelline is an alkaloid with chemical formula C7H7NO2 and CAS number 535-83-1. Trigonelline is a product of the metabolism of niacin (vitamin B3) which is excreted in the urine. High amounts of trigonelline have been found in arabica coffee, fenugreeks, and common peas. Another foods such as yellow bell peppers, orange bellpeppers and muskmelons also contain trigonelline but in lower concentrations. Trigonelline has also been detected but not quantified in several different foods, such as rices, triticales, alfalfa, cereals and cereal products, and ryes. Trigonelline in the urine is a biomarker for the consumption of coffee, legumes and soy products.
(±)-Tryptophan is a dietary supplement, nutrient.Tryptophan is one of the 20 standard amino acids, as well as an essential amino acid in the human diet. Only the L-stereoisomer of tryptophan is used in structural or enzyme proteins, but the D-stereoisomer is occasionally found in naturally produced peptides (for example, the marine venom peptide contryphan). (Wikipedia
Lenticin or hypaphorine is a compound found in lentil extracts.  It can also be detected in blood after an individual has consumed lentils and may therefore serve as a food biomarker. Lenticin is an indole alkaloid that is essentially an N-methylated form of tryptophan.  It is known to be a sleep-inducing compound (PMID: 18571406).  In plants it is an agonist of the plant hormone indole acetic acid.
Lenticin or hypaphorine is a compound found in lentil extracts.  It can also be detected in blood after an individual has consumed lentils and may therefore serve as a food biomarker. Lenticin is an indole alkaloid that is essentially an N-methylated form of tryptophan.  It is known to be a sleep-inducing compound (PMID: 18571406).  In plants it is an agonist of the plant hormone indole acetic acid.
Lenticin or hypaphorine is a compound found in lentil extracts.  It can also be detected in blood after an individual has consumed lentils and may therefore serve as a food biomarker. Lenticin is an indole alkaloid that is essentially an N-methylated form of tryptophan.  It is known to be a sleep-inducing compound (PMID: 18571406).  In plants it is an agonist of the plant hormone indole acetic acid.
Tyramine is a monoamine compound derived from the amino acid tyrosine. Tyramine is metabolized by the enzyme monoamine oxidase. In foods, it is often produced by the decarboxylation of tyrosine during fermentation or decay. Foods containing considerable amounts of tyramine include fish, chocolate, alcoholic beverages, cheese, soy sauce, sauerkraut, and processed meat. A large dietary intake of tyramine can cause an increase in systolic blood pressure of 30 mmHg or more. Tyramine acts as a neurotransmitter via a G protein-coupled receptor with high affinity for tyramine called TA1. The TA1 receptor is found in the brain as well as peripheral tissues including the kidney. An indirect sympathomimetic, Tyramine can also serve as a substrate for adrenergic uptake systems and monoamine oxidase so it prolongs the actions of adrenergic transmitters. It also provokes transmitter release from adrenergic terminals. Tyramine is a biomarker for the consumption of cheese
Uridine diphosphategalactose (UDPgal) is a nucleoside diphosphate sugar which can be epimerized into UDPglucose for entry into the mainstream of carbohydrate metabolism. UDPgal is a pivotal compound in the metabolism of galactose. UDPgal is a product of the galactose-l-phosphate uridyl transferase (EC 2.7.7.10) reaction but may also be made from Glucose-l-P, involving uridine diphosphate galactose-4-epimerase (EC 5.1.3.2). UDPgal is the necessary galactosyl donor of galactose in the metabolism to incorporate it into complex oligosaccharides, glycoproteins and glycolipids (galactosides). Defective galactosylation of complex glycoconjugates exists in tissues from galactosemic patients. There is a tendency for galactosemic red cell UDPgal to be in the low normal range with a high uridine diphosphate glucose to UDP-gal ratio. This may reflect an inability of red cell UDPgal-4'-epimerase to maintain a normal ratio and consequently higher levels of UDPgal. In the more complex white blood cells and cultured fibroblasts, the UDPgal content and the uridine diphosphate glucose to UDPgal ratio of galactosemics are normal. Therefore, defective galactosylation observed in galactosemic fibroblasts must result from a defect in the transfer of galactose from UDPgal to these moieties. (PMID: 2122114, 7671968).
Uridine diphosphate-N-acetylglucosamine (uridine 5'-diphosphate-GlcNAc, or UDP-Glc-NAc) is an acetylated aminosugar nucleotide. UDP-GlcNAc is the donor substrate for modification of nucleocytoplasmic proteins at serine and threonine residues with N-acetylglucosamine (O-GlcNAc). Nutrient sensing in mammals is done through the hexosamine biosynthetic pathway (HSP), which produces uridine 5'-diphospho-N-acetylglucosamine (UDP-Glc-NAc) as its end product. Mammals respond to nutrient excess by activating O-GlcNAcylation (addition of O-linked N-acetylglucosamine). O-GlcNAc addition (and removal) is key to histone remodeling, transcription, proliferation, apoptosis, and proteasomal degradation. This nutrient-responsive signaling pathway also modulates important cellular pathways, including the insulin signaling cascade in. Alterations in O-GlcNAc metabolism are associated with various human diseases including diabetes mellitus and neurodegeneration. (PMID: 16317114) Due to the chemical makeup of UDP-GlcNAc, it is well positioned to serve as a glucose sensor in that it is a high-energy compound that requires and/or responds to glucose, amino acid, fatty acid and nucleotide metabolism for synthesis. Elevated levels of O-GlcNAc have an effect on insulin-stimulated glucose uptake. (PMID: 12678487).
Uridine diphosphate-N-acetylglucosamine (uridine 5'-diphosphate-GlcNAc, or UDP-Glc-NAc) is an acetylated aminosugar nucleotide. UDP-GlcNAc is the donor substrate for modification of nucleocytoplasmic proteins at serine and threonine residues with N-acetylglucosamine (O-GlcNAc). Nutrient sensing in mammals is done through the hexosamine biosynthetic pathway (HSP), which produces uridine 5'-diphospho-N-acetylglucosamine (UDP-Glc-NAc) as its end product. Mammals respond to nutrient excess by activating O-GlcNAcylation (addition of O-linked N-acetylglucosamine). O-GlcNAc addition (and removal) is key to histone remodeling, transcription, proliferation, apoptosis, and proteasomal degradation. This nutrient-responsive signaling pathway also modulates important cellular pathways, including the insulin signaling cascade in. Alterations in O-GlcNAc metabolism are associated with various human diseases including diabetes mellitus and neurodegeneration. (PMID: 16317114) Due to the chemical makeup of UDP-GlcNAc, it is well positioned to serve as a glucose sensor in that it is a high-energy compound that requires and/or responds to glucose, amino acid, fatty acid and nucleotide metabolism for synthesis. Elevated levels of O-GlcNAc have an effect on insulin-stimulated glucose uptake. (PMID: 12678487).
Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
Urocanic acid (CAS: 104-98-3) is a breakdown (deamination) product of histidine. In the liver, urocanic acid is an intermediate in the conversion of histidine to glutamic acid, whereas, in the epidermis, it accumulates and may be both a UV protectant and an immunoregulator. Urocanic acid (UA) exists as a trans isomer (t-UA, approximately 30 mg/cm2) in the uppermost layer of the skin (stratum corneum). t-UA is formed as the cells of the second layer of the skin become metabolically inactive. During this process, proteins and membranes degrade, histidine is released, and histidase (histidine ammonia lyase) catalyzes the deamination of histidine to form t-UA. t-UA accumulates in the epidermis until removal by either the monthly skin renewal cycle or sweat. Upon absorption of UV light, the naturally occurring t-UA isomerizes to its cis form, c-UA. Because DNA lesions (e.g., pyrimidine dimers) in the lower epidermis can result from UV-B absorption, initial research proposed that t-UA acted as a natural sunscreen absorbing UV-B in the stratum corneum before the damaging rays could penetrate into lower epidermal zones. Researchers have found that c-UA also suppresses contact hypersensitivity and delayed hypersensitivity, reduces the Langerhans cell count in the epidermis, prolongs skin-graft survival time, and affects natural killer cell activity. (E)-Urocanic acid is found in mushrooms. It has been isolated from Coprinus atramentarius (common ink cap) and Phallus impudicus (common stinkhorn).
Ursodeoxycholic acid, also known as ursodeoxycholate or acid deoxyursocholic, belongs to the class of organic compounds known as dihydroxy bile acids, alcohols and derivatives. Dihydroxy bile acids, alcohols and derivatives are compounds containing or derived from a bile acid or alcohol, and which bears exactly two carboxylic acid groups. Ursodeoxycholic acid is a very hydrophobic molecule, practically insoluble in water, and relatively neutral.
Verapamil is only found in individuals that have used or taken this drug. Verapamil is a calcium channel blocker that is a class IV anti-arrhythmia agent. [PubChem]Verapamil inhibits voltage-dependent calcium channels. Specifically, its effect on L-type calcium channels in the heart causes a reduction in ionotropy and chronotropy, thuis reducing heart rate and blood pressure. Verapamil's mechanism of effect in cluster headache is thought to be linked to its calcium-channel blocker effect, but which channel subtypes are involved is presently not known. [PubChem] Calcium channel antagonists can be quite toxic. In the management of poisoning, early recognition is critical. Calcium channel antagonists are frequently prescribed, and the potential for serious morbidity and mortality with over dosage is significant. Ingestion of these agents should be suspected in any patient who presents in an overdose situation with unexplained hypotension and conduction abnormalities. The potential for toxicity should be noted in patients with underlying hepatic or renal dysfunction who are receiving therapeutic doses. (PMID 8213877).
Xanthine, also known as 2,6-dioxopurine, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Xanthine is also classified as an oxopurine. An oxopurine in which the purine ring is substituted by oxo groups at positions 2 and 6 and N-9 is protonated. Xanthine exists in all living species, ranging from bacteria to plants to humans. In plants, several stimulants can be derived from xanthine, including caffeine, theophylline, and theobromine. Derivatives of xanthine (known collectively as xanthines) are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in the treatment of asthma or influenza symptoms. Within humans, xanthine participates in a number of enzymatic reactions. In particular, xanthine can be biosynthesized from guanine; which is mediated by the enzyme guanine deaminase. In addition, xanthine and ribose 1-phosphate can be biosynthesized from xanthosine through the action of the enzyme purine nucleoside phosphorylase. In humans and other primates, xanthine can be converted to uric acid by the action of the xanthine oxidase enzyme. People with rare genetic disorders, specifically xanthinuria and Lesch‚ÄìNyhan syndrome, lack sufficient xanthine oxidase and cannot convert xanthine to uric acid. Individuals with xanthinuria have unusually high concentrations of xanthine in their blood and urine, which can lead to health problems such as renal failure and xanthine kidney stones. Individuals with Lesch-Nyhan syndrome have a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). The HGPRT deficiency causes a build-up of uric acid in all body fluids. This results in both high levels of uric acid in the blood and urine, associated with severe gout and kidney problems. Neurological signs include poor muscle control and moderate intellectual disability.
Xanthine, also known as 2,6-dioxopurine, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Xanthine is also classified as an oxopurine. An oxopurine in which the purine ring is substituted by oxo groups at positions 2 and 6 and N-9 is protonated. Xanthine exists in all living species, ranging from bacteria to plants to humans. In plants, several stimulants can be derived from xanthine, including caffeine, theophylline, and theobromine. Derivatives of xanthine (known collectively as xanthines) are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in the treatment of asthma or influenza symptoms. Within humans, xanthine participates in a number of enzymatic reactions. In particular, xanthine can be biosynthesized from guanine; which is mediated by the enzyme guanine deaminase. In addition, xanthine and ribose 1-phosphate can be biosynthesized from xanthosine through the action of the enzyme purine nucleoside phosphorylase. In humans and other primates, xanthine can be converted to uric acid by the action of the xanthine oxidase enzyme. People with rare genetic disorders, specifically xanthinuria and Lesch‚ÄìNyhan syndrome, lack sufficient xanthine oxidase and cannot convert xanthine to uric acid. Individuals with xanthinuria have unusually high concentrations of xanthine in their blood and urine, which can lead to health problems such as renal failure and xanthine kidney stones. Individuals with Lesch-Nyhan syndrome have a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). The HGPRT deficiency causes a build-up of uric acid in all body fluids. This results in both high levels of uric acid in the blood and urine, associated with severe gout and kidney problems. Neurological signs include poor muscle control and moderate intellectual disability.
Xanthine, also known as 2,6-dioxopurine, belongs to the class of organic compounds known as xanthines. These are purine derivatives with a ketone group conjugated at carbons 2 and 6 of the purine moiety. Xanthine is also classified as an oxopurine. An oxopurine in which the purine ring is substituted by oxo groups at positions 2 and 6 and N-9 is protonated. Xanthine exists in all living species, ranging from bacteria to plants to humans. In plants, several stimulants can be derived from xanthine, including caffeine, theophylline, and theobromine. Derivatives of xanthine (known collectively as xanthines) are a group of alkaloids commonly used for their effects as mild stimulants and as bronchodilators, notably in the treatment of asthma or influenza symptoms. Within humans, xanthine participates in a number of enzymatic reactions. In particular, xanthine can be biosynthesized from guanine; which is mediated by the enzyme guanine deaminase. In addition, xanthine and ribose 1-phosphate can be biosynthesized from xanthosine through the action of the enzyme purine nucleoside phosphorylase. In humans and other primates, xanthine can be converted to uric acid by the action of the xanthine oxidase enzyme. People with rare genetic disorders, specifically xanthinuria and Lesch‚ÄìNyhan syndrome, lack sufficient xanthine oxidase and cannot convert xanthine to uric acid. Individuals with xanthinuria have unusually high concentrations of xanthine in their blood and urine, which can lead to health problems such as renal failure and xanthine kidney stones. Individuals with Lesch-Nyhan syndrome have a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). The HGPRT deficiency causes a build-up of uric acid in all body fluids. This results in both high levels of uric acid in the blood and urine, associated with severe gout and kidney problems. Neurological signs include poor muscle control and moderate intellectual disability.
Xanthosine, also known as xanthine riboside, belongs to the class of organic compounds known as purine nucleosides. Purine nucleosides are compounds comprising a purine base attached to a ribosyl or deoxyribosyl moiety. Xanthosine is a nucleoside derived from xanthine and ribose. Xanthosine exists in all living species, ranging from bacteria to plants to humans. In plants xanthosine is the biosynthetic precursor to 7-methylxanthosine which is produced by the action of the enzyme known as 7-methylxanthosine synthase. 7-Methylxanthosine in turn is the precursor to theobromine (the active alkaloid in chocolate), which in turn is the precursor to caffeine, the active alkaloid in coffee and tea. Within humans, xanthosine participates in a number of enzymatic reactions. In particular, xanthosine can be biosynthesized from xanthylic acid; which is catalyzed by the enzyme cytosolic purine 5'-nucleotidase. In addition, xanthosine can be converted into xanthine and ribose 1-phosphate; which is mediated by the enzyme purine nucleoside phosphorylase. Xanthosine monophosphate (XMP) is an intermediate in purine metabolism, formed from IMP (inosine monophosphate).
Xanthurenic acid, also known as xanthurenate or 8-hydroxykynurenic acid, is a member of the class of compounds known as quinoline carboxylic acids. Quinoline carboxylic acids are quinolines in which the quinoline ring system is substituted by a carboxyl group at one or more positions. Xanthurenic acid is slightly soluble (in water). Xanthurenic acid can be found primarily in blood, feces, and urine, as well as in human epidermis tissue. Within the cell, xanthurenic acid is primarily located in the membrane. Xanthurenic acid exists in all eukaryotes, ranging from yeast to humans. In humans, xanthurenic acid is involved in the tryptophan metabolism. Moreover, xanthurenic acid is found to be associated with citrullinemia type I, which is an inborn error of metabolism. Xanthurenic acid is a metabolite from tryptophan catabolism. It is a substrate of the enzyme methyltransferases (EC 2.1.1.-) in pathway tryptophan metabolism (KEGG).
Xanthylic acid is an important metabolic intermediate in the Purine Metabolism, and is a product or substrate of the enzymes Inosine monophosphate dehydrogenase (EC 1.1.1.205), Hypoxanthine phosphoribosyltransferase (EC 2.4.2.8), Xanthine phosphoribosyltransferase (EC 2.4.2.22), 5'-Ribonucleotide phosphohydrolase (EC 3.1.3.5), Ap4A hydrolase (EC 3.6.1.17), Nucleoside-triphosphate diphosphatase (EC 3.6.1.19), Phosphoribosylamine-glycine ligase (EC 6.3.4.1), and glutamine amidotransferase (EC 6.3.5.2). (KEGG) Xanthylic acid can also be used in quantitative measurements of the Inosine monophosphate dehydrogenase enzyme activities in purine metabolism. This measurement is important for optimal thiopurine therapy for children with acute lymphoblastic leukaemia (ALL). (PMID: 16725387).