Monosialogangliosides of rabbit skeletal muscle. Characterization of N-acetylneuraminosyl lacto-N-noroctaosyl ceramide.

Rabbit skeletal muscle contained 28.4 nanomol/g wet weight of lipid-bound sialic acid, and 73.4% of the total lipid-bound sialic acid was recovered in a monosialoganglioside fraction. Monosialoganglioside components were isolated and the structures were determined by exoglycosidase treatment and permethylation analysis. The major monosialoganglioside was GM3 (73.2% of monosialogangliosides), and gangliosides of the lacto-series with at least three repeating units of lactosamine, Gal(beta, 1-4)GlcNAc(beta, 1-3), were identified. A newly found ganglioside was N-acetylneuraminosyl lacto-N-noroctaosyl ceramide, NeuAc(alpha, 2-3)Gal(beta, 1-4)GlcNAc (beta, 1-3)Gal(beta, 1-4)GlcNAc(beta, 1-3)Gal(beta, 1-4)GlcNAc(beta, 1-3)Gal(beta, 1-4)Glc(beta, 1-1)ceramide. The amounts of lacto-series gangliosides in the monosialoganglioside fraction were as follows: sialosyl lacto-N-neotetraosyl ceramide (9.8%), sialosyl lacto-N-norhexaosyl ceramide (11.9%) and sialosyl lacto-N-noroctaosyl ceramide (5.1%). N-Glycolylneuraminic acid was found in sialosyl lacto-N-neotetraosyl ceramide and sialosyl lacto-N-norhexaosyl ceramide but the amount was less than 0.2%. The mobilities of lacto-series gangliosides were compared with those of ganglio-series gangliosides. Fatty acid and long chain base compositions were also determined.