K-067. Characterization of Fibrinolytic Enzyme, "Fibzyme" Excreted by Bacillus subtilis MK-15

K. H. Oh1, B. U. Lee2, Y. S. Cho1, B. H. Sohn1;
1Soonchunhyang Univ., Asan, REPUBLIC OF KOREA, 2Kosin Univ., Busan, REPUBLIC OF KOREA.

The purpose of this work was to evaluate whether the fibrinolytic enzyme named "Fibzyme' can prevent blood from clotting or dissolve the clots. Bacillus subtilis MK-15 used for the production of the enzyme was originally isolated from traditionally Korean soybean-fermented food. Physicochemical properties (e.g., pH, temperature, metal ions, inhibitors) of Fibzyme prepared by a series of purification steps (e.g., ammonium sulfate precipitation, ion exchange chromatography, gel filtration) were characterized. Optimal temperature and pH were 30°C and 7, respectively. Several metal ions including Hg+, Ag+, Zn++ demonstrated the inhibitory effect on the activity of the fibzyme. Several chemicals (e.g., SDS, EDTA, CDTA, AHA, L-cyctein, thiourea) inhibited the enzyme activity. Molecular weight was determined to approximately 41 kDa by SDS-PAGE and the band showing enzyme activity was observed by SDS-Fibrin Zymography. Maximal specific activity of Fibzyme was approximately 304.5 units/mg. The fibrinolytic activity of the enzyme was approximately 37 times greater than that of plasmin by surface area of clear zone, demonstrating its identity as a potent fibrinolytic enzyme. Comparative fibrinolytic activities of Fibzyme and aspirin were carried out in vitro using rat blood. As the results, no blood aggregation was examined in the addition of Fibzyme (500 μg/μl) or aspirin (20 μg/μl) during 48 hours of reaction period. Pre-formed blood clot was dissolved within 24 hours of reaction in the addtion of Fibzyme, whereas no dissolution of the blood clot was achieved in the addition of aspirin. This work indicates that Fibzyme has the activities of prevention of blood clotting as well as dissolution of the pre-formed clot. Fibzyme derived from natural fermented soybean has proved as healthy food for blood circulation even through in vitro studies. In consequence, it has the potential to be developed as functional food additives and drugs to prevent or cure cardiovascular diseases.