Antithrombin, Antithrombin III, AT 3, AT III, AT3, AT3D, ATIII, Heparin cofactor I, Serpin C1, Serpin family C member 1, SERPINC1, THPH7,
Most important serine protease inhibitor in plasma that regulates the blood coagulation cascade. AT-III inhibits thrombin as well as factors IXa, Xa and XIa. Its inhibitory activity is greatly enhanced in the presence of heparin.