Thrombin Activatable Fibrinolysis Inhibitor (TAFI)

TAFI, Thrombin Activatable Fibrinolytic Inhibitor, (also known as carboxypeptidase U and plasma carboxypeptidase B) is a 60,000 D molecular ratio glycoprotein (proenzyme form) present in rabbit plasma1 that modulates fibrinolysis in vivo. This proenzyme is converted to a 35,000 D molecular ratio active form, TAFIa, following proteolytic cleavage by the thrombin/ thrombomodulin complex. TAFIa possesses carboxypeptidase activity with a preference for cleaving lysine and arginine residues from the c-terminus of proteins. Modulation of fibrinolysis occurs when TAFIa cleaves C-terminal arginine and lysine residues of partially degraded fibrin.2,4,5 The removal of the c-terminus arginine and lysine residues from fibrin inhibits the continued degradation of fibrin by tPA activated plasmin.3