Prekallikrein (PK)

Prekallikrein (PK), also known as Fletcher factor, is a serine protease precursor (zymogen) found in plasma. It is the inactive precursor of plasma kallikrein, an enzyme that plays a central role in the intrinsic pathway of blood coagulation and in the generation of bradykinin, a potent vasoactive peptide. It is activated to kallikrein by activated Factor XII (FXIIa) which is a key step in initiating intrinsic coagulation and inflammatory responses. Its deficiency causes markedly prolonged activated partial thromboplastin time (aPTT) but typically does not result in bleeding symptoms.

Other names

Fletcher factorPlasma prekallikreinKLKB1

N/A (Prekallikrein is a zymogen, not typically directly targeted by drugs. However, its activation to kallikrein is a key step)