A plasma glycoprotein (antithrombin III, serpinC1, 464 aa) that inhibits serine proteases in the blood coagulation cascade (thrombin and factors IXa, Xa, and XIa). Its inhibitory activity is enhanced by heparin. Antithrombin III deficiency is an important risk factor for hereditary thrombophilia, in which there is a tendency to recurrent thrombosis. Antithrombins I, II, and IV were terms used in early studies on coagulation and are obsolete.
Subjects: Medicine and Health.