The Biosynthesis of Glycosaminoglycans

The sugar components of acidic glycosaminoglycans have long been known to be derived from glucose without alteration of the sugar ring (Topper & Lipton, 1953). The discovery of the nucleotide sugars by Caputto et al. (1950) and Park (1952) radically transformed the outlook on the biosynthesis of polysaccharides. It became rapidly apparent, not only that nucleotide sugars were the ‘activated’ donors for polysaccharide synthesis, but that a great many interconversions between sugar species were performed at this level of conjugation (Ginsburg, 1964). Here the concern is with the nucleotide sugars associated with glycosaminoglycan synthesis, namely the UDP derivatives of glucuronate, iduronate, xylose, N-acetylglucosamine, N-acetylgalactosamine and galactose, and with their fate up to the polymerization and subsequent export of the finished polymer.