Coagulation factor XII (F12)

Factor XII is a serum glycoprotein that participates in the initiation of blood coagulation, fibrinolysis, and the creation of bradykinin and angiotensin. Prekallikrein is cleaved by factor XII to form kallikrein, which then cleaves factor XII initially to alpha-factor XIIa and then trypsin cleaves it to beta- factor XIIa.

Alpha-factor XIIa activates factor XI to factor XIa. .