Isolation and characterization of two isomers of brain tetrasialogangliosides

Two isomers of tetrasialogangliosides were isolated and purified to homogeneity from human, bovine, chicken, and cod fish brains by employing DEAE-Sephadex and Iatrobeads column chromatographies. The tetrasialogangliosides of human, bovine, and chicken brains appeared to be identical because they had identical mobilities on thin layer plates developed with six different solvent systems. The tetrasialoganglioside of cod fish brain moved slower on thin layer plates than the tetrasialoganglioside from the other species. The ganglioside preparations were subjected to mild acid hydrolysis, neuraminidase treatment, and periodate oxidation followed by borohydride reduction. The structures of the two isomers were differentiated from each other by controlled mild acid hydrolysis in both aqueous and organic solvents. The structure IV3(NeuAc)2,II3(NeuAc)2-GgOse4ceramide is assigned to the tetrasialoganglioside of human, bovine, and chicken brains; and the structure IV3NeuAc,II2(NeuAc)3-GgOse4ceramide is assigned to that of cod fish brain. The possible pathways for the synthesis of the two tetrasialogangliosides are discussed.