ISOLATION OF FIBRINOPEPTIDES FORMED DURING INTRAVASCULAR COAGULATION IN DOGS

Purified canine fibrinopeptide A was incubated in canine serum in vitro. The trichloroacetic acid‐soluble degradation products were isolated by preparative electrophoresis, and identified by means of amino acid analyses. Desarginino‐fibrinopeptide A and free arginine were found, indicating that C‐terminal arginine is split off from fibrinopeptide A during incubation in serum in vitro. An attempt was made to isolated fibrinopeptides and possible fibrinopeptide degradation products from the blood of thrombin‐treated dogs. A slow intravenous infusion of thrombin was given to dogs, until the blood became non‐clottable. Non‐protein material of the “plasma” was subjected to gel filtration, ion‐exchange chromatography and preparative electrophoresis. Two fractions, which could be related to the fibrinopeptides, were identified. The electrophoretic mobility of the fractions and of their tryptic digests, as well as the amino acid analyses, indicated that one fraction consisted of fibrinopeptide A and the other of desarginino‐fibrinopeptide A. © 1969 Scandinavian Physiological Society