Characterization of a metalloprotease from an isolate Bacillus thuringiensis 29-126 in animal feces collected from a zoological garden in Japan

An extracellular metalloprotease, Btmp, was partially purified from the culture supernatant of Bacillus thuringiensis 29- 126, isolated from animal feces collected in a zoological garden in Japan, by ultrafiltration, ammonium sulfate precipitation, and a set of chromatography on Sephadex G-75 and High-Q. The molecular mass of the protease was estimated to be 60 kDa by SDS-PAGE. The enzyme showed optimum activity at 50 oC and pH 6.0, and had a half-life of 14 min at 50 oC. The enzyme activity was not influenced by Na+, K+, As+, Mg+2, Ca2+, Ba2+, and phenylmethylsulfonyl fluoride, but it was moderately inhibited by Zn+2 at a concentration of 1.0 mM, while the activity was significantly inhibited to less than 50 % by Cu2+, Co2+, Cd2+, and ethylenediaminetetraacetic acid. Interestingly, the enzyme was activated to 178 % by 1.0 mM of Mn2+. From these results, it may be suggested that the protease is a novel extracellular manganeseactivated metalloprotease. KCI Citation Count: 0