NCIt definition : The potassium salt form of heparin, a sulfur-rich glycosaminoglycan with anticoagulant
activity. Heparin binds to antithrombin III to form a heparin-antithrombin III complex.
The complex binds to and inactivates thrombin (factor IIa) and other activated clotting
factors, such as factors IXa, Xa, XIa, and XIIa. The inactivation of thrombin prevents
the polymerization of fibrinogen to fibrin and the subsequent formation of blood clots.;