文摘
A bifunctional thrombolytic serine protease (ulvease) having both direct-acting fibrinolytic and plasminogen-activating properties was purified from the green alga, Ulva pertusa. Ulvease had maximum fibrinolytic activity at 40 °C and pH 7.0, and the activity was inhibited by Cu2+ and Zn2+. Fibrinolytic activity of ulvease was higher than that of plasmin and u-PA by fibrin plate assay and displayed both plasmin and plasminogen activator-like activities. Ulvease preferentially hydrolyzed the Aα- and Bβ-chains of fibrinogen, but the γ-chain was appeared unaffected. Ulvease prolonged APTT and PT. PFA-100 assay showed that it delayed the closure times of citrated whole human blood. Ulvease showed a strong thrombolytic ability and safety in vivo, which is better than that of u-PA. It protected mice from collagen- and epinephrine-induced pulmonary thromboembolism. These results suggest that ulvease may have a potential clinical application for the treatment and prevention of thrombosis. Keywords Anticoagulant Antithrombosis Bifunctional enzyme Fibrinolysis Ulva pertusa