Coagulation inhibitor elicited by thrombin.

A protein fraction present in bovine prothrombin complex, or in prothrombin-free preparations obtained from serum, is converted by thrombin into an anticoagulant that strongly interferes with the intrinsic pathway of blood coagulation and with thrombin formation, initiated also by the extrinsic mechanism. If one assumes that a similar phenomenon takes place in vivo, the association between thrombosis and hemorrhage may be better understood.