The chemistry of gangliosides: A review

Gangliosides are lipids which are found primarily in gray matter of the brain, with lesser amounts in white matter and in some tissues outside the central nervous system. At least ten different gangliosides have been isolated from brain, four of which are major components accounting for over 90% of the mixture. Three of these and possibly the fourth possess a common asialo unit consisting of ceramide, glucose, galactose, and N‐acetylgalactosamine in the molar ratios 1蝘1蝘2蝘1. Structural work emanating from the laboratories of Kuhn, Klenk, Svennerholm, and others has shown the major monosialoganglioside to beG A L ( 1 → 3 ) G A L N a c ( 1 → 4 ) G A L ( 1 → 4 ) G L U ( 1 → 1 ) C E R A M I D EN A N AThe two major disialo species contain this unit plus an additional NANA attached to terminal galactose in one case, and to the first NANA in the other. The major trisialo may also be related to these, though its structure is not yet settled. The minor gangliosides generally contain fewer carbohydrate units. One of these has been found to resemble the major ganglioside of Tay‐Sachs disease, which is a monosialo species lacking the terminal galactose of the major normal brain types. A number of neurological disorders, including other sphingolipidoses, have characteristic alterations in both pattern and level of brain gangliosides.