C1-inhibitor (C1INH) functions as a regulator of the activation of the classical complement pathway and of the contact activation system of kinin generation and coagulation. Its primary biologically relevant target proteinases are C1r, C1s, coagulation factors , Xenopus/Amphibian,Ia and , Xenopus/Amphibian,IIa, and plasma kallikrein. C1-inhibitor consists of one polypeptide chain and has a molecular mass of 104 kDa. Serum concentration has been determined to 180 ug/ml. This antibody is specific for human C1INH.