Heparin glycosaminoglycan disaccharides

Chai, W., Rosankiewicz, J. R., and Lawson, A. M. (1995). TLC-LSIM of neoglycolipids of glycosaminoglycan disaccharides and of oxymercuration cleavage products of heparin fragments that contain unsaturated uronic acid. Carbohydr. Res. 269 111-124. 

Figure 2. Structures of the glycosaminoglycans and their linkage regions to protein. Two disaccharide repeating units are shown to emphasize the microheterogeneity that exists in some cases. Heparan sulfate and heparin show many structural similarities. However, heparan sulfate contains more GlcNAc(a-1 — 4)GlcUA repeating units fewer glucosamine residues are N-sulfated, and few iduronic acid residues are sulfated at C2.

Figure 5 Biosynthesis and structure of glycosaminoglycans. Synthesis u GlcAT-l. The repeating disaccharides of heparin/HS, CS, and DS are shown.

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. 

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