Heparin HS chains

Heparin has been used clinically for decades to prevent and treat thromboembolic disease and is isolated on an industrial scale from animal tissues, in particular pig intestinal mucosa. The conesponding physiological blood anticoagulant is presumably not heparin, but an HS species that is located on the surface of vascular endothelial cells. Both heparin and HS contain a specific pentasaccharide sequence that binds and activates the plasma proteinase inhibitor AT. This pentasaccharide sequence (4) is present only in a subfraction of heparin and HS preparations. It displays a characteristic structural feature, namely a 3-0-sulfated GlcN residue, that is only rarely seen in other portions of heparin/HS chains. 

Many proteins bind to motifs in DS, heparin, and HS chains that feature IdoA residues [2, 52], Unfortunately, L-idose and IdoA are very expensive sugars, prompting chemists who wish to target IdoA-containing sequences to use cheaper alternatives for building block preparation [53], Abundant D-glucose-based compounds are often... 

Recent studies on heparin/HS biosynthesis have been focused on the isolation and molecular cloning of the various enzymes that catalyze this process. Such enzymes include the glycosyltransferase(s) responsible for generating the initial polysaccharide chain, as well as a variety of enzymes involved in subsequent mod-... 

The HS chains of serglycin are highly sulfated and rich in iduronic acid and, when processed by commercial means, yield the pharmaceutical product heparin. There is no qualitative difference between the HS chains of serglycin, sometimes referred to as heparin chains, and the HS chains on other HSPGs rather the structures represent a continuum, with the serglycin HS chain likely reflecting the lack of unmodified domains [35]. These differences presumably result from distinct isoforms of the biosynthetic enzymes. 

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