The separation of active and inactive forms of heparin.

Heparin has been fractionated into two distinct forms. The isolation of these species was accomplished by sucrose density gradient centrifugation of heparin mixed with antithrombin-heparin cofactor. Approximately $\text{1}\text{3}$ of this mucopolysaccharide was bound to antithrombin-heparin cofactor and had potent anticoagulant activity. This component was clearly separated from the remaining $\text{2}\text{3}$ of the heparin which could not form a stable complex with antithrombin-heparin cofactor and had minimal anticoagulant activity.