Thrombolytic, anticoagulant and antiplatelet activities of codiase, a bi-functional fibrinolytic enzyme from Codium fragile

摘要

Thrombosis is a leading cause of morbidity and mortality throughout the world. Thrombolytic agents are important for both the prevention and treatment of thrombosis. In this study, codiase, a new bifunctional fibrinolytic serine protease having thrombolytic, anticoagulant, and antiplatelet activities was purified from marine green alga, Codium fragile. The molecular weight of the enzyme was estimated to be 48.9 kDa by SDS-PAGE, and mass spectrometry. Fibrin zymography analysis showed an active band with similar molecular weight. The N-terminal sequence was found to be APKASTDQTLPL, which is different from that of other known fibrinolytic enzymes. Codiase displayed maximum activity at 30 degrees C and pH 6.0, and the activity was inhibited by Zn2+ and Fe2+ Moreover, the enzyme activity was strongly inhibited by serine protease inhibitor such as PMSF. Codiase exhibited high specificity for the substrate S-2288, and the K-m and V-max values for this substrate were found to be 0.24 mM and 79 U/ml respectively. Fibrin plate assays revealed that it was able to hydrolyze fibrin clot either directly or by activation of plasminogen. Codiase effectively hydrolyzed fibrin and fibrinogen, preferentially degrading alpha- and A alpha chains, followed by gamma-gamma, and gamma-chains. However, it provoked slower degradation of B beta and beta-chains. The structural change of fibrin clot and fibrinogen by codiase was also detected by FTIR-ATR spectroscopy analysis. In vitro and in vivo studies revealed that codiase reduces thrombosis in concentrationdependent manner. Codiase was found to prolong activated partial thromboplastin time (APTT), and prothrombin time (PT). PFA-100 studies showed that codiase prolonged the closure time (CT) of citrated whole human blood. These favorable antithrombotic profiles together with its anticoagulant and platelet disaggregation properties, and lack of toxicity to mice and NIH-3T3 cells, make it a potential agent for thrombolytic therapy. (C) 2013 Elsevier Masson SAS. All rights reserved.