ABSTRACT
The affinity of thrombin for fibrin led early investigators to question the enzymatic action of thrombin on fibrinogen. Buchanan was able to isolate a clot-promoting material from fibrin formed on the dilution of blood with water. Abildgaard also reported that neither dextran nor ficoll affected the rate of the appearance of N-terminal glycine during the action of thrombin on fibrinogen, showing that these components have a direct effect on thrombin. Thrombin bound to fibrin equilibrated with thrombin solution in a slow process. These investigators also reported that thrombin bound to fibrin was partially protected from inactivation by antithrombin and that thrombin activity could be obtained from the fibrin clot by treatment with plasmin, which was also partially protected from inactivation by anti-thrombin. One consequence of the binding of thrombin by fibrin is the “inactivation” of thrombin by removing it from the bulk solution.
