Heparan sulfate glycosaminoglycan disaccharides

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.

A glycosaminoglycan is a heteropolysaccharide consisting of repeating disaccharide sequences, where each disaccharide contains a hexosamine and a hexuronic acid chondroitin sulfate, dermatan sulfate, heparin, and heparan sulfate). However, in keratan sulfate, the hexuronic acid moiety is replaced by a hexose [8, 28]. These... 

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