Human Factor XII is a single chain glycoprotein with a molecular weight of about 80,000. Once activated, principally from the action of kallikrein, Factor XII is converted into an active serine protease (Factor α-Xlla) that functions in the in vivo initiation of blood coagulation, fibrinolysis, and kinin formation. Human Factor XII has been purified by ion exchange chromatography. MW: 80.00 kDa. Purity ≥95%