[Composition of the carbohydrate component and fatty acids of the chief gangliosides of the brains of cartilaginous fish].

Ganglioside composition has been studied in the brain of 5 Elasmobranch fishes (3 sharks: Carcharhinus longimanus, Carcharhinus sp., Squalus acanthias and 2 rays: Dasyatis pastinaca, Raja clavata). For the identification of ganglioside fractions, molar ratio of glucose, galactose, NANA and sphingosine as well as the presence of hexosamine were determined in the main gangliosides from the brain of the shark C. longimanus. The data obtained indicate that the majority of brain gangliosides in Elasmobranchs contain a reduced carbohydrate chain as compared to the main gangliosides from mammalian brain. Thus in C. longimanus and Carcharhinus sp. GD3, disialoganglioside containing only two hexose residues in its molecule, constitutes approximately 30 per cent of ganglioside sialic acid. Considerable amounts of GD2, GM3 and GM2 were found in Elasmobranch brain as well. Investigation of fatty acid composition of gangliosides from the brain of C. longimanus revealed the predominance of stearic acid (C18:0) in all the fractions studied.