High-Performance Liquid Chromatography of Gangliosides

Gangliosides are normal components of the plasma membrane of vertebrate cells [1] and are particularly abundant in the nervous system. Their concen¬ tration at the level of the cortex gray matter is about one-tenth that of total phospholipids [2]. They are asymmetrically located in the outer lipid layer of the membrane [3] and exhibit strong amphiphilic properties [4]. Gangli¬ osides are glycosphingolipids constituted by a hydrophylic sialic acid-con¬ taining oligosaccharide and a hydrophobic ceramide portion, connected by a glycosidic linkage. The oligosaccharide portion protrudes from the outer membrane surface, and the ceramide moiety is inserted into the lipid core of the membrane. Gangliosides occur in nature in a large number of different species. The number and chemical features of sialic acid, and the number, type, and sequence of the individual sugars of the neutral oligosaccharide core are the basis for a wide variety of chemical structures. Moreover, a ganglioside with a homogeneous oligosaccharide portion can be a mixture of several molecular species differing in their ceramide composition (fatty acid of different hydrocarbon chain length, with or without double bonds or hydroxyl groups; long chain bases of different chain length, with or without double bonds).