Molecular Basis for the Susceptibility of Fibrin-bound Thrombin to Inactivation by Heparin Cofactor II in the Presence of Dermatan Sulfate but Not Heparin*

Although fibrin-bound thrombin is resistant to inactivation by heparin.antithrombin and heparin.heparin cofactor II complexes, indirect studies in plasma systems suggest that the dermatan sulfate.heparin cofactor II complex can inhibit fibrin-bound thrombin. Herein we demonstrate that fibrin monomer produces a 240-fold decrease in the heparin-catalyzed rate of thrombin inhibition by heparin cofactor II but reduces the dermatan sulfate-catalyzed …