Figure 2.

Structures of disaccharide-repeating units of glycosaminoglycans. (a) Three different disaccharide-repeating units found in heparin. The disaccharide of -IdoA2S-GlcNS6S- is most abundantly present in heparin, where IdoA2S represents 2-O-sulfo-iduronic acid; and GlcNS6S represents 6-O-sulfo-N-sulfoglucosamine. (b) The disaccharide-repeating units of dermatan sulfate and chondroitin sulfate. The disaccharide-repeating units of dermatan and chondroitin sulfates contain galactosamine. Furthermore, the uronic acid and galactosamine residues are linked through α1→3 linkages. (c) The disaccharide-repeating unit of oversulfated glycosaminoglycans, oversulfated chondroitin sulfate (OSCS), an adulterant product of chemically modified chondroitin sulfates found in contaminated heparin products. R₁ = −H or −SO₃Na; R₂ = −H, −Ac or −SO₃Na.