Prekallikrein is the glycosylated single chain zymogen precursor of the plasma serine protease kallikrein. Plasma prekallikrein circulates with kininogen and is activated by Factor XIIa in the intrinsic coagulation pathway. Kallikrein activates plasminogen in fibrinolysis and cleaves kininogen in the bradykinin system of vasodilation. Prekallikrein deficiency is rare and causes increased activated partial thromboplastin time. Elevated plasma prekallikrein is associated with diabetes and cardiovascular disease.
