FATTY-ACID AND LONG-CHAIN BASE COMPOSITION OF GANGLIOSIDES ISOLATED FROM ADULT HUMAN-BRAIN

A series of major and minor ganglioside species were isolated from a single human adult brain and analyzed for their lipophilic composition. Hematosides, GM3 and GD3, each showing double bands on TLC, were separated into the upper band and lower band fractions to be analyzed for the heterogeneity of their ceramide moieties. The upper band fractions of GM3 were found to contain relatively high amounts of longer-chain fatty acids (C20-C26), whereas the lower band fractions contained high amounts of shorter-chain fatty acids (C16-C18). Compared to other gangliosides which contain hexosamine, the 2 hematosides contained a smaller proportion of stearic acid. The proportion of 4-eicosasphingenine increased with increasing sialic acid content in gangliosides. In the biosynthesis of various gangliosides, N-acetylhexosamine is preferentially transferred to hematosides rich in stearic acid and sialic acid residues are preferentially transferred to 4-eicosasphingenine-containing species.