Thrombin is an active enzyme in the earliest steps of the blood clot formation, generated from its circulating inactive precursor prothrombin. Thrombin is a glycoprotein formed by two peptides chains of 36 and 259 amino acids linked by disulfure bonds. Three important sites have been identified on the surface of the enzyme: The catalytic site that confers to the molecule its serine protease activity, the exosite one responsible for the binding of the substrate (fibrinogen or thrombin receptor) and the exosite two responsible for the binding of antithrombin III and inactivation of thrombin. The molecular mass of thrombin is ~37 kDa.
Activation peptide fragment 1; Activation peptide fragment 2; Coagulation factor II; coagulation factor II (thrombin); Coagulation factor II (Thrombin) receptor-like 1; prepro-coagulation factor II; Prothombin; Prothrombin; prothrombin B-chain; serine protease; Thrombin heavy chain; Thrombin light chain