THE HUMAN PLASMIN-DERIVED LIGHT (B) CHAIN.STREPTOKINASE COMPLEX - A 2ND-GENERATION THROMBOLYTIC AGENT

  • 1 January 1983
    • journal article
    • research article
    • Vol. 50 (4), 787-791
Abstract
Specific assay methods for the human plasmin-derived light (B) chain .cntdot. streptokinase (B .cntdot. SK) complex, in terms of both streptokinase (SK) and urokinase (UK) IU, are described. The kinetic properties of various SK activator complexes with plasminogen, Val442-plasmin and the plasmin-derived light (B) chain were compared to SK in terms of their catalytic efficiencies and Lineweaver-Burk plots. Similar kinetic data, and Lineweaver-Burk plots, are described for both highly purified high-MW UK and low MW UK, including different clinical UK preparations. The B .cntdot. SK complex has the highest catalytic efficiency of all the activator species studied. The Lineweaver-Burk plots of each of the various activator species are fingerprints of the enzymatic character of the activator. The B .cntdot. SK complex is more like UK than SK, as an activator, in activating non-human plasminogen species. The biological half-life of the B .cntdot. SK complex, in a dog model, was determined to be .apprx. 4 h which is longer than the biological half-life(s) of SK in the same animal model, namely 0.6 h (47%) and 2.8 h (53%). This new 2nd-generation activator complex may prove to be a useful thrombolytic agent in the treatment of thromboembolic diseases.