Highly active heparin species with multiple binding sites for antithrombin

Abstract

Porcine heparin has been fractionated by Sephadex G-100 gel filtration and affinity chromatography into mucopolysaccharide species with approximate molecular sizes of 20,000 daltons, and 7000 daltons, respectively. The larger component has a specific anticoagulant activity of 738 USP units/mg and contains two binding regions for antithrombin. The smaller component has a specific anticoagulant activity of 363 USP units/mg and possesses only a single interaction site for the inhibitor. These results provide the first demonstration that heparin molecules may bear multiple binding sites for antithrombin.