All of the following are anti coagulants .. except

Ref Robbins 7/e p125-126;129-130;9/e p121-118 Von Willebrand Factor's primary function is binding to other proteins, in paicular factor VIII, and it is impoant in platelet adhesion to wound sites. It is not an enzyme and, thus, has no catalytic activity. VWF binds to a number of cells and molecules. The most impoant ones are: Factor VIII is bound to VWF while inactive in circulation; factor VIII degrades rapidly when not bound to VWF. Factor VIII is released from VWF by the action of thrombin. In the absence of VWF, factor VIII has a half-life of 1-2 hours; when carried by intact VWF, factor VIII has a half-life of 8-12 hours. VWF binds to collagen, e.g., when collagen is exposed beneath endothelial cells due to damage occurring to the blood vessel. Endothelium also releases VWF which forms additional links between the platelets' glycoprotein Ib/IX/V and the collagen fibrils