Coagulation studies on the electrophoretic fractions of AFIF

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

Anticoagulant fraction of incubated fibrinogen (AFIF), obtained from human fibrinogen by simple incubation or from bovine fibrinogen (prepared by the method of Laki) after addition of streptokinase-activated human fibrinolysin and incubation for several days, was subjected to continuous flow paper electrophoresis in 0.02 m, pH 8.6 Veronal buffer, at 800 v and about 40 ma. Both kinds of AFIF separated into two components: a major one having the same electrophoretic mobility as the intact fibrinogen and a second more electronegative amounting up to 21% of the first. The latter migrated with a mobility intermediate between that of albumin and -globulins or between the mobilities of -and ß-globulin fractions of human plasma, depending on the origin of the preparation human or bovine, respectively. Further studies showed that if the incubation of human fibrinogen was interrupted before the sample became completely unclottable by thrombin, the AFIF obtained showed only the first component on electrophoresis. Both fractions of human AFIF were found able to inhibit the clotting of bovine fibrinogen by thrombin to the same extent as the original sample, however, only the second component inhibited the rate of formation of plasma thromboplastin when added to a thromboplastin generating system.