THE EFFECT OF GLYCEROL MEDIUM ON THE ACTIVATION OF HUMAN PLASMINOGEN BY STREPTOKINASE AND ON THE ACTION OF THE ENZYME, PLASMIN

Abstract

A 50% glycerol medium affected the activation of plasminogen by streptokinase (SK) and the activity of plasmin (formed by glycerol incubation) on p-toluene-sulphonyl-L-arginine methyl ester (TAMe) in the following ways:(1) TAMe interfered strongly with the activation of plasminogen by SK in a glycerol medium but not in a water medium under the same conditions.(2) SK inhibited the action of plasmin on TAMe in a glycerol medium, but in a water medium SK increased the rate of hydrolysis of TAMe, the extent of the increase depending upon pH.(3) Phosphate buffer inhibited the activation of plasminogen by SK in a glycerol medium but not in a water medium. In the glycerol medium a lag period in the formation of enzyme was found, particularly noted with a phosphate buffer, and the lag period increased with increasing concentration of the buffer.(4) Phosphate buffer inhibited the action of plasmin on TAMe in a glycerol medium but not in a water medium.Mechanisms of activation of plasminogen by SK are discussed. The data presented support the postulate that a reaction takes place between plasmin and SK to form an enzyme called "activator".