Vibrio extracellular protease with prothrombin activation and fibrinolytic activities.

A 36 kDa extracellular metalloprotease (designated to as vEP-MO6) was purified and characterized from Vibrio vulnificus sp. strain MO6 24/0. vEP-MO6 cleaved azocasein and a few other proteins such as prothrombin, plasminogen, fibrinogen and Factor Xa, which are associated with the blood coagulation pathway. The enzyme activity of vEP-MO6 was inhibited by EDTA, which was reversed by the addition of excess divalent cations. vEP-MO6 showed little or no activity toward various chromogenic substrates that are specific for other proteases. The cleavage of prothrombin by vEP-MO6 produced active thrombin, as revealed by an activity assay with thrombin-specific chromogenic substrate and Western blot analysis with anti-thrombin antibody. The enzyme also actively hydrolyzed fibrin polymer as well as the cross-linked fibrin. These results suggest that vEP-MO6 is a prothrombin-activating and cross-linked fibrin-degrading enzyme belonging to the metalloprotease family.