In Vitro Studies on the Mechanism of the Antifibrino-lytic Action of E-Aminocaproic Acid (EACA)

Abstract

1. It has been found that EACA does not inhibit activation of human plasminogen into plasmin by SK and UK in a concentration of 5 × 10^–2 M. The activation of bovine plasminogen by SK and UK is inhibited by this concentration of EACA but not by a lower one. 2. EACA in concentrations of 1,5 × 10^–1 – 10^–4 M does not inhibit casein proteolysis by plasmin. The proteolysis of fibrinogen and fibrin measured by the release of TCA soluble tyrosine is inhibited by EACA in concentrations of 1,5 × 10^–1 – 10^–2 M. 3. The lysis of non-stabilized clots by plasmin measured in a test tube was inhibited by an EACA concentration of 5 × 10^–3 – 5 × 10^–4 M. The lysis of stabilized clots by plasmin was inhibited by an EACA concentration of 10^–5 M. 4. On the basis of experimental findings and data given in literature the authors postulate that the mechanism of the antifibrinolytic effects of EACA consists mainly in a modification of plasmin action on fibrin. These effects are dependent on the structure of the fibrin clots.