A vitamin-K dependent zymogen present in the blood, which, upon activation by thrombin and thrombomodulin exerts anticoagulant properties by inactivating factors Va and VIIIa at the rate-limiting steps of thrombin formation.
An anticlotting (glyco) protein that prevents post-operative arterial clot formation when administered intravenously. May be synergistic (in its anticlotting effect) with tissue plasminogen activator (tPA).
A plasma protein that inhibits coagulation factors V and XIII, preventing excessive clotting. Deficiency of this protein or resistance to its effects may lead to deep venous thrombosis and pulmonary embolism.