Zymogen precursor of the plasma serine protease kallikrein. Human Prekallikrein is a single chain gamma globulin glycoprotein that participates in the early phase of contact activation, kinin formation and fibrinolysis. Prekallikrein purity is >95percent by SDS-PAGE and shows no reduction upon incubation with 2-mercaptoethanol. Prepared from plasma found negative by FDA accepted methods for Anti-HIV1/2, Anti-HTLV I & II, HBsAg, Anti-HCV, Syphilis, HBC Ab, HIV-1 p24 Ag or HIV-1 RNA, HCV RNA and HBV RNA. Donors are screened for CJD (Creutzfeldt-Jakob Disease).