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KMID : 0903519900330040337
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Journal of the Korean Society of Agricultural Chemistry and Biotechnology
1990 Volume.33 No. 4 p.337 ~ p.342
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Characteristics of the protease from the extreme halophile , Halobacterium sp .
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Abstract
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The protease from Halobacterium sp. was purified by ethanol precipitation and gel filtration on Sephadex G-75 and G-100. The purified enzyme was found to be homogeneous by polyacrylamide gel electrophoresis. It´s specific activity was 364units/㎎ protein and yield was 14% of the total activity of the culture filtrate. The Km value against casein was determined to be 4.2 × 10-´M by Lineweaver-Burk plot. The optimal temperature and pH for the enzyme activity were 35℃ and pH 8.0, respectively. The enzyme was stable from 5.0 to 11.0 at relatively wide range of pH but was inactivated at the temperature above 50℃. Ca^(2+) and Mg^(2+) appeared to react as activatois whereas Fe^(3+), Zn^(2+), Cu^(2+), Hg^(2+) and Cd^(2+) as inhibitors. the enzyme activity reduced with increasing the concentration of NaCl : the apparent activity with 2M NaCl was 65% as compared with that without the salt However the enzyme was unstable without salts : the activity was lost when dialyzed against distilled water for 2hr, whereas maintained against d.1M solution of CaCl₂ for 6hr.
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