Halomonas sp . ES 10 이 생산하는 alkaline protease 의 특성 = Characteristics of the alkaline protease from the moderate halophile , Halomonas sp . ES 10

다국어 초록 (Multilingual Abstract)

The protease from Halomonas sp. ES 10 was purified by methanol precipitation, gel filtration on Sephadex G-150 and G-200, and ion exchange chromatography on DEAE-Sephadex A-50. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. The specific activity of purified enzyme was 1,014 units/㎎ protein, and the yield of the total activity from the culture filtrate was 7%. The optimal temperature and pH for the enzyme activity were 35℃, and pH 11.0, respectively. And the enzyme was stable in the range of pH 7.5∼11.0. The residual activity of the enzyme was 70%, when the enzyme was incubated at 50℃ for 40 min. The Km value of the enzyme was 7.4 ㎎/㎖ to milk casein. Li^+, Ca^(2+), SDS and Tween 80 were appeared to activators, whereas Hg^(2+) and EDTA to inhibitors. The addition of DFP and PMSF showed the relative enzyme activities of 63% and 107%, respectively, suggesting that the enzyme may not belong to serine type protease. When the alkaline protease was treated with 0.5 M and 1 M NaCl, the relative enzyme activities were 95% and 65%, respectively. This enzyme showed 20% and 15% higher enzyme activity than that of Aspergillus oryzae (Sigma Chemical Company product, P4755) in the presence of 0.5 M and 1 M NaCl.