Hyaluronic acid glycosaminoglycan disaccharides

The PhEur 2005 describes sodium hyaluronate as the sodium salt of hyaluronic acid, a glycosaminoglycan consisting of D-glucuronic acid and N-acetyl-o-glucosamine disaccharide imits. 

At least seven types of glycosaminoglycans exist, which differ in the monosaccharides present in their repeating disaccharide units—chondroitin sulfate, dermatan sulfate, heparin, heparin sulfate, hyaluronic acid, and keratan sulfates I and II. Except for hyaluronic acid, the glycosaminoglycans are linked to proteins, usually attached covalently to serine or threonine residues (Fig. 49.9). Keratan sulfate I is attached to asparagine. 

Starting with the simplest of the glycosaminoglycan structures, hyaluronic acid has a disaccharide repeating structure (I) composed of the... 

Young human placenta contains more glycosaminoglycan than term placenta (L9). Although there are similar quantities of hyaluronic acid and chondroitin 4- and 6-sulfates, the younger placenta contains a greater proportion of chondroitin. The chondroitin sulfates of the early tissue also contain a higher proportion of unsulfated disaccharide units, and the dermatan sulfate of the young tissue is more susceptible to hyaluroni-dase (EC 3.2.1.35) than term tissue. 

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