Biochem/physiol Actions

C1 esterase inhibitor functions as a serine proteinase inhibitor. The concentration of C1 esterase inhibitor protein is reduced to 10-30% of normal in patients with angioedema secondary to C1 esterase inhibitor deficiency (85% of patients with Hereditary Angioedema (HAE)); in 15% of patients with HAE, the concentrations of the inhibitor protein is normal but function is markedly reduced. C1 esterase inhibitor deficiency is a rare condition resulting in facial swelling and abdominal cramping. Usually the condition is hereditary, though it may also occur when the protein is non-functional. C1 esterase inhibitor deficiencies also disturb the fibrinolytic system, the intrinsic coagulation pathway and the complement pathway.

General description

C1 esterase inhibitor is a single chain glycoprotein which inhibits C1, C1r, C1s, plasma kallikrein, factors XIa, XIIa and plasmin of the blood clotting system. It is present in the plasma at 16-33 mg/100mL. It is part of the serpin family.

Physical form

Frozen in 20 mM potassium phosphate, pH 7.0, with 250 mM KCl.