After activation by thrombin, the mature protein negatively regulates fibrinolysis by removing plasminogen binding sites to fibrin. TAFI (Thrombin Activatable Fibrinolysis Inhibitor) is a single chain glycoprotein synthesized by the liver and circulating at a plasma concentration of 50 nM. Thrombin cleaves the zymogen and releases the 92 amino acids activating peptide containing 4 N-glycosylation sites and the plamsinogen recognition site. TAFI plays an important role in the interaction between the fibrinolytic, anticoagulant and procoagulant systems.