ABSTRACT
Antithrombin is a serine protease inhibitor (serpin) that inhibits a number of plasma proteases. In particular, antithrombin functions as one of the major natural anticoagulants by irreversibly inhibiting a number of the enzymes formed during activation of the coagulation cascade in vivo (1). Antithrombin can form serpin-protease inhibitor complexes with activated factor (F) XII (FXIIa), FXIa, FIXa, FXa, and thrombin (1-3). Within this group of coagulant proteases, antithrombin has the fastest rate of reaction with thrombin, its preferred reactant (4).
