The Structure and the Function of Gangliosides

Gangliosides are found in the brain and other organs, and are composed of sphingosine, fatty acids, hexoses, and sialic acid. Types of gangliosides differ in the fatty acids and the sugar residues. The carbohydrate residue in the quantitatively predominating brain gangliosides is ganglio‐N‐tetraose, a tetrasaccharide. In these gangliosides, this residue combines with one or more molecules of sialic acid. The oligosaccharide part is a carrier of serologic properties. Gangliosides are characteristic lipid components of some neuronal membranes in the central nervous system, and can be localized on the synaptic apparatus of nerve cells in the cerebral cortex. Their site of occurrence and physiological action point to their participation in the transmission of impulses. It was in the brains of the mentally ill that gangliosides were first discoverd, and indeed their pathologic accumulation can possibly be attributed to congenital defect of enzymes involved in their synthesis or metabolism. Gangliosides are produced from their components by acceptor‐specific transferases.