04-09-2011, 10:31 AM
Heparin binds to Antithrombin III (ATIII) and dramatically accelerates its enzymatic activity. As a serine protease inhibitor, ATIII-heparin can inactivate the serine proteases of the intrinsic pathway, XIIIa, XIa, IXa, and Xa - but what is its primary anti-coagulative activity?
1-ATIII stimulates the release of plasminogen activators from tissues
2-Activated ATIII dissolves the cross-linking of fibrin by proteolysis
3-ATIII catalyses the binding of thrombin to thrombomodulin, allowing Protein C to be activated
4-One molecule of ATIII inactivates one molecule of thrombin; heparin is catalytic
5-Plasmin is cleaved from plasminogen by ATIII
1-ATIII stimulates the release of plasminogen activators from tissues
2-Activated ATIII dissolves the cross-linking of fibrin by proteolysis
3-ATIII catalyses the binding of thrombin to thrombomodulin, allowing Protein C to be activated
4-One molecule of ATIII inactivates one molecule of thrombin; heparin is catalytic
5-Plasmin is cleaved from plasminogen by ATIII