TAFI, thrombin-activatable fibrinolytic inhibitor, (also known as carboxypeptidase U and plasma pro-carboxypeptidase B) is a 60kDa molecular weight glycoprotein (proenzyme form) found in human plasma that modulates fibrinolysis.
This proenzyme is converted to an active form of molecular ratio 35kDa, TAFIa, after proteolytic cleavage by the thrombin / thrombomodulin complex. TAFIa possesses carboxypeptidase activity with a preference for cleavage of lysine and arginine residues from the end of proteins.