Ganglioside GD1b (d18:0/18:1(11Z)) is a ganglioside. A ganglioside is a compound composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (AKA n-acetylneuraminic acid, NANA) linked on the sugar chain. The 60+ known gangliosides differ mainly in the position and number of NANA residues. It is a component of the cell plasma membrane that modulates cell signal transduction events. It appears that they concentrate in lipid rafts. They have recently been found to be highly important in immunology. Natural and semisynthetic gangliosides are considered possible therapeutics for neurodegenerative disorders. Gangliosides are more complex glycosphingolipids in which oligosaccharide chains containing N-acetylneuraminic acid (NeuNAc) are attached to a ceramide. NeuNAc, an acetylated derivative of the carbohydrate sialic acid, makes the head groups of Gangliosides anionic. NB: the M in GM2 stands for monosialo, i.e., one NeuNAc residue. GM2 is the second monosialo ganglioside characterized, thus the subscript 2. Their structural diversity results from variation in the composition and sequence of the sugar residues. In all Gangliosides, the ceramide is linked through its C-1 to a beta-glucosyl residue, which, in turn, is bound to a beta-galactosyl residue. (Wikipedia) Particularly, Ganglioside GD1b (d18:0/18:1(11Z)) is a GD1b ganglioside, a glycosphingolipid (ceramide and oligosaccharide) or oligoglycosylceramide with one or more sialic acids (i.e. n-acetylneuraminic acid) linked on the sugar chain. It is a component the cell plasma membrane which modulates cell signal transduction events. Gangliosides have been found to be highly important in immunology. Ganglioside GD3 carries a net-negative charge at pH 7.0 and is acidic. Gangliosides can amount to 6% of the weight of lipids from brain, but they are found at low levels in all animal tissues. Gangliosides are glycosphingolipids. There are four types of glycosphingolipids, the cerebrosides, sulfatides, globosides and gangliosides. Gangliosides are very similar to globosides except that they also contain N-acetyl neuraminic acid (NANA) in varying amounts. The specific names for the gangliosides provide information about their structure. The letter G refers to ganglioside, and the subscripts M, D, T and Q indicate that the molecule contains mono-, di-, tri and quatra-sialic acid. The numbered subscripts 1, 2 and 3 refer to the carbohydrate sequence that is attached to the ceramide. In particular, 1 stands for GalGalNAcGalGlc-ceramide, 2 stands for GalNAcGalGlc-ceramide and 3 stands for GalGlc-ceramide. Deficiencies in lysosomal enzymes that degrade the carbohydrate portions of various gangliosides are responsible for a number of lysosomal storage diseases such as Tay-Sachs disease, Sandhoff disease, and GM1 gangliosidosis. The carbohydrate portion of the ganglioside GM1 is the site of attachment of cholera toxin, the protein secreted by Vibrio cholerae.