TAFI is supplied in its 60 kDa zymogen form. The N-terminal of TAFI contains four N-linked glycans and a plasminogen recognition sequence. Hydrolysis of the activation peptide by thrombin releases a 36-kDa active proteolytic domain homologous to tissue carboxypeptidase B. Complexation with thrombomodulin increases thrombin activation of TAFI 1250 fold. TAFI exerts it′s inhibition of fibrinolytic activity by binding to plasminogen and by cleaving C-terminal lysine residues of fibrin resulting in the reduction of plasmin and tPA binding sites on fibrin. Experiments in TAFI-deficient mice point to a regulatory role on complement C5a.

Solution containing 20 mM Hepes and 150 mM Sodium chloride. pH 7.4

One unit will hydrolyze 1 micromole of Hippuryl-L-Arginine per minute at pH 7.4 at 25 °C.