[The effect of heparin on the proteolytic and fibrinolytic activity on plasmin(ogen) and fibrin clot lysis].

The effect of heparin on the proteolytic and fibrinolytic activities of plasmin and plasminogen was studied. Heparin at a concentration of 6.3.10(-6) M did not change the caseinolytic activity of plasmin and plasminogen stimulated by streptokinase but suppressed their fibrinolytic activity. At concentrations from 2.10(-8) to 0.5.10(-6) M heparin increased, whereas at 1.10(-6)-4.10(-6) M reduced the time of desAAfibrin clot half-lysis by plasmin. Within the concentration range of 2.10(-8) to 4.10(-6) M heparin did not change the time of the clot half-lysis by glu-plasminogen and slightly decreased the time of fibrin clot half-lysis by lys-plasminogen in the presence of the tissue activator. It was supposed that heparin inhibits the fibrinolytic effect of plasmin by way of formation of complexes with plasmin and reduction of plasmin specificity to the solid phase substrate, i. e., polymeric fibrin.