Bacillus subtillis YG-95가 생산하는 protease를 ammonium sulfate$(35{sim}85%)$ precipitation, DEAE-separose 6B, sephadex G-100을 통해 분리, 정제하였고 정제된 효소의 특성을 조사하였다. SDS-PAGE로 확인된 효소의 분자량은 약 43 kilodalton이었다. 효소반응의 최적 pH 및 최적온도는 각각 약 pH 10.0와 $55^{circ}C$이었으며, 효소는 $pH;5{sim}12$ 까지 넓은 pH범위에서 안정성을 보였고, $45^{circ}C$까지의 온도에서 안정하였다. 본 효소는 $Fe^{3+}$와 $Al^{3+}$에 의해서 활성이 저해되었으며, 저해제 중에서는 O-Phenanthroline, PMSF, SDS에 의해서 80%이상 저해를 받았고 SPI에 대한 기질 친화도는 $K_m$은 1.28 mg/mL이었다.
The protease produced by Bacillus subtilis YG-95 was purified by precipitating with ammonium sulfate, DEAE-sepharose 6B and Sephadex G-100 column chromatogtaphies and its purified enzymological characteritics were investigated. The molecular weight of purified protease was estimated about 43kilodalton by SDS PAGE The optimum pH and temperature for the purified protease activity were pH 10.0 and $55^{circ}C$, respectively. The enzyme was stable in broad range of pH 5.0 to 12.0. and at the below $45^{circ}C$. The purified enzyme activty was inhibited by $Fe^{3+}$ and $Al^{3+}$. The activity was significantly inhibited more than 80% by O-Phenanthroline, PMSF and SDS. The $K_m$ value of the purified enzyme against Soy Protein Isolate as a substrate was 1.28 mg/ml.
