[Inhibition of the process of Glu-plasminogen activation by tissue activator with fibrin, DDE-complex, and D-dimer using alpha-2-antiplasmin].

The alpha-2-antiplasmin influence on the Glu-plasminogen activation by tissue activator both on fibrin and fibrin(ogen) fragments was investigated. The kinetics of activation was studied and velocity of this process in the absence and presence of the inhibitor was calculated. It was established that alpha-2-antiplasmin decreased the velocity of Glu-plasminogen activation on desAABBfibrin, DDE-complex and DD-dimer and did no influence upon proenzyme activation on fibrinogen fragment--Ho1-DSK. In the presence of fibrin plasminogen activation linear related to the amount added tissue activator in limit concentration from 5 before 50 units/ml. It was shown that alpha-2-antiplasmin reduced the activation velocity with used concentration of tissue activator. Fibrin hydrolysis by plasmin, forming on its surface during the plasminogen activation by tissue activator, was also inhibited with alpha-2-antiplasmin. The obtained results are explained by the influence of the inhibitor on formation of the triple complex between plasminogen, tissue activator and fibrin, and competition of the alpha-2-antiplasmin for lysine-binding sites of tissue activator kringle 2 or for binding sites of the activator on fibrin.