Structure. Disialogangliosides (GD) belong to the group of gangliosides within the sphingolipids. Their structure consists of a ceramide backbone linked to an oligosaccharide. Two of the sugar molecules are sialic acids. The total number of sugar molecules is part of the name of GD subclasses: GD1 contains six sugars, GD2 five, and GD3 four. The ceramide backbone of disialogangliosides contains two hydrocarbon chains: a long-chain base which is linked to a fatty acid via an amide bond. The fatty acid and the long-chain base can be of variable length, hydroxylated, and contain double bonds.
Function. Disialogangliosides are mostly related to the central nervous system. GD1 gangliosides belong to the major gangliosides of the mammal brain, but some species also posses anti-inflammatory properties. In cancers, specifically melanomas and neuroblastomas, GD2 gangliosides are found at high concentrations. Thus, they are considered tumor-associated antigens. GD3 gangliosides are fundamental in neurogenesis and essential for stem cell self-renewal in the brain. Yet, GD3 levels are elevated in melanomas and neuroblastomas, too.
