Urokinase-Induced Fibrinolysis of ¹²⁵I-Fibrin

Summary

By means of the density-gradient separation of soluble fibrin split products from ¹²⁵I-labeled fibrin in 0.8-ml gradients, a micro-technique for the measurement of urokinase activation of plasminogen was developed. The conditions necessary to maintain first-order activation kinetics were obtained and incorporated into the micro-technique, thus providing a linear micro-assay of 0.1-ml volumes of urokinase in the range of 2.5-50.0 CTA units.

^** Supported by Contract AT-(40-l)-3195 with the U.S. Atomic Energy Commission and by Grants HE-08929 and NB-06233 with the National Institutes of Health, USPHS.

^** This work is taken from a dissertation submitted in partial fulfillment of the Ph.D. degree, Duke University. Present address, Department of Surgery, Duke University Medical Center.

• References

• 1 Alkjaersig N, Fletcher A. P, Sherry S. The mechanism of clot dissolution by plasmin. J. clin. Invest 38: 1086 1959;
• 2 Berg W. Plasminogen and urokinase determination based on the lysis time method. Acta med. scand Suppl. 478 1967;
• 3 Clement W. E, McNicol G. P. The preparation and use of I¹³¹-tagged fibrinogen to demonstrate fibrinolysis. J. clin. Pathol 12: 544 1959;
• 4 de Wit Dudok G. D, Krijnen H. W, den Ottolander G. J. H. The measurement of fibrinolytic activity with ¹³¹I-labeled clots. I. The Methods. Thrombos. Diathes. haemorrh. (Stuttg) 08: 315 1962;
• 5 Eisen H. N, Keston A. S. The immunologic reactivity of bovine serum albumin labeled with trace amounts of radioactive iodine (I¹³¹). J. Immunol 63: 71 1949;
• 6 Fritz R. B, Lassiter S, Day E. D. A quantitative precipitin study of porcine fibrinogen employing paired labels. J. Immunol 98: 1213 1967;
• 7 Kline D. L. Purification and crystallization of plasminogen (profibrinolysin). J. biol. Chem 204: 949 1953;
• 8 Laki K. The polymerization of proteins: The action of thrombin on fibrinogen. Arch. Biochem 32: 317 1951;
• 9 McNicol G. P, Douglas A. S, Bayley C. Experience with streptokinase infusions. Lancet II: 1297 1962;
• 10 Merrills R. J, Shaw J. T. B. Kinetics of fibrin clot lysis. Biochem. J 106: 101 1968;
• 11 Remmert L. F, Cohen P. Partial purification and properties of a proteolytic enzyme of human serum. J. biol. Chem 181: 431 1949;
• 12 Robbins K. G, Summaria L. Purification of human plasminogen and plasmin by gel filtration on Sephadex and Chromatography on Diethylaminoethyl-Sephadex. J. biol. Chem 238: 952 1963;
• 13 Sawyer W. D, Fletcher A. P, Alkjaersig N, Sherry S. Studies on the thrombolytic activity of human plasma. J. clin. Invest 38: 426 1959;
• 14 Shulman N. R, Tagnon H. J. Proteolytic activity determined with a substrate tagged with radioactive iodine. J. biol. Chem 186: 69 1950;