The Significance of Plasma Inhibitor(s) in the Control of Fibrinolytic (Plasmin) Activity in Blood

Summary

A single one minute wash with three volumes of iso-amyl alcohol will remove all effective antithrombin and antiplasmin activity from plasma. On centrifugation, a clear inhibitor-free plasma with prothrombin activity and with no measurable loss of plasminogen or plasmin is obtained. Studies were carried out on both dog and human plasma. When iso-amyl alcohol treated plasma is stored either at room temperature or at 4° C, the plasminogen in it spontaneously converts to plasmin. The rate at which it does this is proportional to the amount of activator present in the original plasma. When stored at -20° C, this plasmin is stable indefinitely and provides an excellent source of plasmin for routine studies. Experiments in which urokinase was added to plasma samples and the mixture allowed to incubate for varying periods of time from 10 minutes to 15 hours before inhibitor was removed, showed that very little plasmin is destroyed by inhibitor. The plasmin-inhibitor complex is largely reversible. Zone electrophoresis studies indicate that iso-amyl alcohol removes alpha globulins, lipoproteins and some glycoproteins.

• References

• 1 Ambeus C. M, and Markus G. 1960; Plasmin-antiplasmin complex as a reservoir of fibrinolytic enzyme. American Journal of Physiology 199: 491.
• 2 Ganrot P. O. 1967; Studies on serum protease inhibitors with special reference to α₂-Macro-globulin. Acta University of Lund II. No 2: 5.
• 3 Heimbuegee N. 1967. On the proteinase inhibitors of human plasma with expecial reference to antithrombin. A. G. Behringwerke; Marburg/Lahn, Germany: 353-361.
• 4 Johnson A. J, Tse A. O, and Newman J. 1964. Preparation of fibrinogen deficient in plasminogen and determination of clottable protein. In: Blood Coagulation, Hemorrhage and Thrombosis. Tocantins L. M, and Kazal L. A. (eds) Grune and Stratton; New York: 462.
• 5 Kohn J. 1961; Lipoprotein staining method for zone electrophoresis. Nature 189: 312.
• 6 Koiu E, and Gronwall A. 1952; Staining of protein-bound carbohydrate after electrophoresis of serum on filter paper. Scandinavian Journal of Clinical and Laboratory Investigations 4: 244.
• 7 Macfarlane R. G, and Pilling J. 1946; Observation on fibrinolysis. Plasminogen, plasmin and antiplasmin content of human blood. Lancet 2: 562.
• 8 Monkhouse F. C, and Milojevic S. 1965; The inactivation of antithrombin by ether, evidence against the existence of antithrombin IV. Canadian Journal of Physiology and Pharmacology 43: 819.
• 9 Monkhouse F. C, and Milojevic S. 1967; Studies on the relation between plasma antithrombin and heparin-cofactor. Canadian Journal of Physiology and Pharmacology 46: 347.
• 10 Monkhouse F. C, Milojevic S, and Schmitt A. 1971; The physiological importance of antithrombin. Thrombosis et Diathesis Haemorrhagica. Suppl 46: 201.
• 11 Norman P. S. 1958; Studies of the plasmin system II. Inhibition of plasmin by serum or plasma. Journal of Experimental Medicine 108: 53.
• 12 Ratnoff O. D, Lepow I. H, and Pillemer H. 1954; The multiplicity of plasmin inhibitors in human serum, demonstrated by the effect of primary amino compounds. Bulletin of the Johns Hopkins Hospital 94: 169.
• 13 Rimon A, Shamash Y, and Shapiro B. 1966; The plasmin inhibitors of human plasma. Journal of Biological Chemistry 241: 5102.