Structure for Hyaluronic Acid

THE mucopolysaccharide hyaluronic acid exists naturally as a hydrated gel. It is the constituent of synovial fluid which acts as a lubricant; it also occurs in the vitreous humour where its function is probably to maintain the precise shape of the eye. Chemically it is a regular, unbranched polymer with a repeating unit of the type (-N-G-)_n where N is N-acetylglucosamine and G is glucuronic acid. The glycosidic linkages N to G and G to N are 1e, 4e and le, 3e respectively (Fig. 1). Our arguments are based on the postulate that both glucopyranose rings are in the C1 chain conformation.