限定分解したＳｔｒｅｐｔｏｋｉｎａｓｅの活性について

Abstract

Streptokinase (SK) reacts stoichiometrically with human plasminogen and plasmin to generate plasminogen activator activity by making complex. In order to clarify the reaction of SK and plasminogen, enzymatic properties of SK were studied. Digested SK with molecular weight of 29K (SK29) was prepared by tryptic digestion of native SK (nSK) with molecular weight of 47K and separated by SDS polyacrylamide gel electrophoresis. SK29 was extracted from the electrophoretic gel, and its fibrinolytic and amidolytic activity was compared with that of nSK. A mixture of SK29 and human plasminogen hydrolyzed only human fibrin, while a mixture of nSK and human plasminogen hydrolyzed human and bovine fibrin (Fig. 2). SK29 showed the ability to activate human plasminogen in the presence of human fibrin (Fig. 3). However, different from nSK, it did not show the ability in the presence of human fibrinogen, bovine fibrin or fibrinogen. These results suggest that human fibrin formation induces comformational changes in the human plasmionogen which results in the generation of an active site by SK29.