Isolation and characterization of a novel ganglioside, monosialosyl pentahexaosyl ceramide from human brain.

A novel monosialosyl ganglioside was isolated from human brain in a yield of 2.1 nmol of the lipid-bound sialic acid per g of wet weight (0.09% of total lipid-bound sialic acid). The ganglioside was resistant to the action of Vibrio cholerae neuraminidase. By treatment with N-acetylhexosaminidase, methylation analysis, CrO3 oxidation, and partial acid hydrolysis, the structure of this ganglioside was determined to be; GalNAc(beta, 1-4)Gal(beta, 1-3)GalNAc(beta, 1-4)Gal(beta, 1-4)Glc(beta, 1-1)ceramide. (formula: see text). The treatment of the ganglioside with 1 N formic acid at 80 degrees C for 2 h produced mainly gangliotetraosyl ceramide, suggesting that the terminal N-acetylgalactosamine was more labile on formic acid treatment than galactose at nonreducing terminal.