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KMID : 0545119990090040469
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Journal of Microbiology and Biotechnology
1999 Volume.9 No. 4 p.469 ~ p.474
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Minor Thermostable Alkaline Protease Produced by Thennoactinomyces sp.E79
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Kim, Young Ok
Lee, Jung Kee/Kandula Sunitha/Kim, Hyung Kwoun/Oh, Tae Kwang
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Abstract
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Thermoactinomyces sp. E79 produced two types of thermostable alkaline proteases extracellularly. A minor protease was separated from a major protease by using DEAE-column chromatography. This enzyme was purified to homogeneity by ammonium sulfate and DEAE-Sepharose ion-exchange chromatography. The purified minor protease showed different biochemical properties compared to the major protease. The molecular mass of the purified enzyme was estimated by SDS-PAGE to be 36 kDa. Its optimum temperature and pH for proteolytic activity against Hammarsten casein were 70℃ and 9.0, respectively. The enzyme was stable up to 75℃ and in an alkaline pH range of 9.0- 11.0. The enzyme was inhibited by phenylmethylsulfonyl fluoride (PMSF) and Hg^2+, indicating that the enzyme may be a cysteine-dependent serine protease. In addition, the enzyme cleaved the endoproteinase substrate, succinyl-Ala-Ala-Pro-Phe-p- nitroanilide, and the K^m value for the substrate was 1.2 mM.
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