Serine metalloprotease with plasmin-like fibrinolytic activity of Serratia marcescens isolated from the Amazon basin

Research on new fibrinolytic agents has been oriented towards the discovery of microbial proteases with plasmin-like activity, as alternative thrombolytic agents for thrombosis treatment. This study reports the characterization of an extracellular serine metalloprotease of approximately 56 kDa, with fibrinolytic and fibrinogenolytic activity, isolated from a S. marcescens strain obtained from the Amazon (CBAM 519). The enzyme showed optimum activity at pH 9 and temperature of 37 °C. Activity was reduced in the presence of Na+, Cu2+ and Fe2+ ions, and increased with Mn2⁺. The enzyme did not show hemolytic activity, nor did it activate plasminogen, but it effectively hydrolyzed fibrin and fibrinogen, rapidly degrading all fibrinogen chains Aα, Bβ and γ. Therefore, fibrinolysis was promoted only by the direct route, with a fast acting, potent fibrinolytic activity. Based on this, we expect the enzyme to be a protease of the plasmin type that directly degrades fibrin. These characteristics demonstrate great potential for its application in the treatment of thrombosis.