Effects of tranexamic acid, CIS-AMCHA, and 6-aminohexanoic acid on the activation rate of plasminogen by urokinase in the presence of clot

When human plasma was mixed with 50 units of urokinase and clotted with thrombin in the presence of S-2251, the hydrolysis of S-2251 in the clot was higher than that in the plasma. The presence of 10 μM of tranexamic acid resulted in decrease in the activation rate of plasminogen in the clot but not in the plasma. Further increase in its concentration resulted in marked increase in plasminogen activation in both clot and plasma. The addition of 6-aminohexanoic acid or cis-AMCHA showed changes in the rate of plasminogen activation similar to that shown in the presence of tranexamic acid. Fifty μM of tranexamic acid totally inhibited urokinase induced clot lysis, while 1 mM of cis-AMCHA and 6-aminohexanoic acid totally inhibited clot lysis. The presence of 1 mM of these ω-aminoacids remarkably increased the activation of plasminogen by urokinase, but no clot lysis was observed.