Effect of Fibrinolysin on the Coagulability of Fibrinogen^[*]

Summary

Streptokinase or glycerol activated human fibrinolysin was added to human plasma and the enzyme action was stopped by the addition of epsilon amino-caproic acid at different time intervals. The clottable fibrinogen content of the mixtures was determined by diluting the plasma with either physiological saline or distilled water, both containing thrombin or thrombin plus calcium chloride. It was found that before the addition of fibrinolysin the values in distilled water containing calcium chloride were higher than the respective values in plain saline or in saline containing calcium chloride. The drop in clottable fibrinogen after the addition of fibrinolysin was more pronounced when the determinations were performed in plain distilled water. Thus, a crossover between the values obtained in plain distilled water and those in saline gradually occurred, the values in distilled water without calcium chloride becoming the lowest. This is at variance with the results obtained in the presence of added AFIF or fibrinolysed fibrinogen where the values in distilled water were always higher than the ones obtained in saline both in the presence and in the absence of calcium chloride. Since the reversal of coagulability of fibrinogen in physiological saline versus distilled water was reproduced only when we mixed partially lysed human fibrinogen with completely lysed human plasma, the conclusion was drawn that three prerequisites are necessary for this phenomenon to occur: a) the fibrinogen must have been acted upon by fibrinolysin; b) the fibrinogen must be of human origin; c) a substance produced by the action of fibrinolysin on a plasmatic factor other than fibrinogen or, possibly, an intact plasmatic factor, must be present.

^* Supported by grants from the Medical Research Council of Canada and the Alberta Heart Foundation. Presented in part at the fourth annual meeting of the Canadian Federation of Biological Societies [Proceedings 4: 65 (1961)].

^** Research Associate, Medical Research Council of Canada.

• References

• 1 Triantaphyllopoulos D. C. Preliminary report on the anticoagulant properties of incubated fibrinogen. Proceedings of the Western Group, Division of Medical Research, National Research, Council of Canada, January 1957 1957; 11: 21
• 2 Triantaphyllopoulos D. C. Anticoagulant effect of incubated fibrinogen. Canad. J. Biochem 1958; 36: 250
• 3 Triantaphyllopoulos D. C. Effects of intravenous injections of the anticoagulant fraction of incubated fibrinogen. Canad. J. biochem. Physiol 1960; 38: 909
• 4 Triantaphyllopoulos D. C. Nature of the thrombin-inhibiting effect of incubated fibrinogen. Amer. J. Physiol 1959; 197: 575
• 5 Niwiarowski S, Kowalski E. Un nouvel anticoagulant derive du fibrinogene Rev. Hémat 1958; 13: 320
• 6 Triantaphyllopoulos D. C. AFIF inhibitor from fibrinogen. Transaction of the Wiesbaden Conference on the Coagulation Balance. Thromb. Diath. haem. (In press.)
• 7 Sgouris J. T, Inman J. K, McCall K. B, Hyndman L. A, erson H. D. The preparation of human fibrinolysin (plasmin). Vox Sang. (Basel) 1960; 5: 357
• 8 Laki K. The polymerization of proteins: the action of thrombin on fibrinogen. Arch. Biochem 1951; 32: 317
• 9 Quick A. J. Hemorrhagic Diseases. Lea x0026; Febiger; Philadelphia: 1957
• 10 Alkjaersig N, Fletcher A. P, Sherry S. E-aminocaproic acid: an inhibitor of plasminogen activation. J. biol. Chem 1959; 234: 832
• 11 Celander D. A, Naschke M. D, Guest M. M. The effect of epsilon aminocaproic acid on fibrinolysin and on activators of Profibrinolysin. Tex. Rep. Biol. Med 1961; 19: 50
• 12 Hussey C. V. Quoted by Quick. A. J.: Hemorrhagic Diseases. Lea x0026; Febiger; Philadelphia: 436 1957