AAFR, substrate for carboxypeptidase B type enzymes. Enzymic removal of the anisylazoformyl (Aaf) moiety is followed by a decrease in substrate absorption at 350 nm (λmax ≈ 350 nm, ε ≈ 19000 M⁻¹ cm⁻¹). The kcat/Km value for hydrolysis by porcine carboxypeptidase B at 25 °C, pH 7.9 (0.05 M Tris buffer) was 1.0 x 10⁶ s⁻¹ M⁻¹.
AAFR has been used to measure the TAFI (thrombin activatable fibrinolysis inhibitor, carboxypeptidase U) activation by thrombin and thrombin-thrombomodulin.