Fibrinolytic Bacterial Enzymes with Thrombolytic Activity

Abstract

This book describes the fibrinolytic enzymes of microbial origin that are able to dissolve endogenous thrombi in vivo. The fibrinolytic enzyme streptokinase for example, is produced by β-hemolytic streptococci and exerts its enzyme action indirectly by activating plasminogen. On the other hand, staphylokinase is produced by Staphylococcus aureus by stoichiometric complexation with plasmin(ogen) that activates other plasminogen molecules. Serrapeptase is a different fibrinolytic enzyme produced by enterobacterium Serratia sp. E-15 with multiple functions including fibrin degradation. In addition, nattokinase is a very promising enzyme produced by Bacillus natto in fermented soybean in the Japanese diet providing them with the lowest rate of thrombosis disorders all over the world. For each fibrinolytic enzyme there is a special focus on the enzyme structure and mechanism of action. In Sect. 6 the methods used for assessment of clot lysis in vitro are discussed: Fibrin plate methods, streptokinase lysis methods, nephelometric methods, dilute blood clot lysis time, euglobulin lysis time, esterolytic, and fluorimetric assays. Finally, hemostasis screening tests are discussed, such as CBC, PT, PTT, TT, fibrinogen, D-dimer, and BT assays. They should be done regularly to check the physiological and fibrinolytic activity of blood to reduce the onset of endogenous thrombi.