Anticoagulant action of TAMe and AFIF

¹ Department of Physiology and Pharmacology, University of Alberta, Edmonton, Canada

The effect of addition of the anticoagulant fraction of incubated fibrinogen (AFIF) or tosylarginine methylester (TAMe) into mixtures of fibrinogen and thrombin was studied. It was found that although TAMe was able to inhibit coagulation when added prior or shortly after thrombin, it acted as procoagulant when added later. These procoagulant properties seemed to depend on the concentration and time of addition of TAMe. The amount of fibrinogen clotted increased with the time interval between the addition of thrombin and that of TAMe. AFIF acted exclusively as anticoagulant, being effective when added during the first two-thirds to five-sixths of the expected thrombin time. Whenever TAMe was added to mixtures of fibrinogen, AFIF, and thrombin, its procoagulant effect was delayed or altogether abolished depending on the time of addition. When, however, TAMe was added to mixtures of fibrinogen and thrombin together with AFIF its procoagulant action appeared unimpaired. Although TAMe delayed only the beginning, AFIF seemed to delay both the beginning and general course of polymerization.