О. V. Matselyukh, N. A. Nidialkova, L. D. Varbanets

Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv;
e-mail: oivanko@yahoo.com

The scheme of isolation and purification of Bacillus thuringiensis ІMV B-7324 peptidase has been developed. This scheme includes ammonium sulfate precipitation and chromatography on neutral and charged TSK-gels. It was found that the enzyme hydrolyzes elastin and fibrin. The molecular weight is 26 kDa. It was shown that the enzyme is an alkaline serine peptidase. The optimal pH of hydrolysis of elastin and fibrin were 9.0 and 10.0, respectively. The optimal temperature of elastin and fibrin hydrolysis are 40 and 50 °C, respectively.  The high stability of the purified preparation in the studied range of pH and temperature was shown. The stabilizing effect of zinc at a concentration of 1 mM on the elastase activity, and the inhibitory effect of other divalent cations under study have been established. The investigated chloride and acetate anions reduced activity by 20%, while phosphate anions increased activity by 15–30%.

Keywords: Bacillus thuringiensis, elastolytic activity, extracellular peptidase, fibrinolytic activity, physico-chemical properties of peptidases, purification