Heparin structure.
Heparins used in therapy are largely constituted by sequences of the trisulfated disaccharide L-iduronic acid-2-sulfate----D-glucosamine-N,6-disulfate. These regular sequences are interrupted by undersulfated (occasionally, oversulfated) sequences containing D-glucuronic acid and N-acetylated D-glucosamine. Different heparin sequences are binding domains for heparin cofactors and plasma proteins. The active site for antithrombin is a specific pentasaccharide sequence containing 3-O-sulfated D-glucosamine. Heparin cofactor-II binds, less specifically, mostly to the regular sequences. The conformational flexibility of iduronic acid residues contributes to the binding versatility and to the 'biological reactivity' of heparin.
Casu
B
B
Istituto di Chimica e Biochimica G. Ronzoni, Milano, Italia.
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D006493:Heparin / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure
D006493:Heparin