Major bases: C18 and C2o sphingosines. Minor amounts of dihydroanalogues. Fatty acids: large amounts of 18:0 (86-95% in brain). Occurrence: mainly in grey matter of brain but also in spleen, erythrocytes, liver kidney. Modern analytical techniques have shown them to be present in a much wider range of tissues than previously realized. Main gangliosides of human brain are GgntI, 2a, 2b, 3a. Gangliosides appear to be confined to the animal kingdom. In man, cattle, horse, main ganglioside outside brain is GLact1-N-glycolyl-neuraminic acid is chief sialic acid in erythrocyte and spleen gangliosides of horse and cattle.
Physical properties: insoluble in non-polar solvents; form micelles in aqueous solution.
Abbreviations in column 2 are the same as in Table 6.7. NAN A = N-acetylneuraminic acid (sialic acid). Wiegandt abbreviations: G = ganglioside. Subscript denotes sialic-free oligosaccharide. Arabic numeral gives number of sialic residues. T = basic tetraose; Tr = triose; Lact = lactose. Trisaccharides and disaccharides that can be derived from the basic tetraose are distinguished by I, II, etc., I describing the sugar that originated from the non-reducing end of the tetrasaccharide; a, b refer to positional isomers with respect to sialic residues.
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