Journal of Microbiology

Eui-Sun Son

2 Articles

Multicatalytic Alkaline Serine Protease from the Psychrotrophic Bacillus amyloliquefaciens S94: Eui-Sun Son , Jong-Il Kim; J. Microbiol. 2003;41(1):58-62.

Abstract PDF: An extracellular protease of Bacillus amyloliquefaciens S94 was purified to apparent homogeneity. The enzyme activity was strongly inhibited by general inhibitor for serine protease, PMSF, suggesting that the enzyme is a serine protease. The purified enzyme activity was inhibited by leucine peptidase inhibitor, bestatin, suggesting that the enzyme is a leucine endopeptidase. The maximum proteolytic activity against different protein substrates occurred at pH 10, 45℃ (protein substrate) and pH 8, 45℃ (synthetic substrate). The purified enzyme was specific in that it readily hydrolyzed substrates with Leu or Lys residues at P1 site. The protease had characteristics of a cold-adapted protein, which was more active for the hydrolysis of synthetic substrate in the range of 15℃ to 45℃, specially at low temperature.

Purification and Characterization of Caseinolytic Extracellular protease from Bacillus amyloliquefaciens S94: Eui-Sun Son , Jong-Il Kim; J. Microbiol. 2002;40(1):26-32.

Abstract PDF: From the culture supernatant of the psychrotrophic strain of Bacillus amyloliquefaciens an extracellular serine protease was purified to apparent homogeneity by successive purification steps using QAE-Sephadex, SP-Sephadex and Sephacryl S-100 column chromatography. The protease is monomeric, with a relative molecular mass of 23,000. It is inhibited by the serine protease inhibitor phenylmethylsulfonyl fluoride, but not by EDTA. The enzyme is most active at pH 9-10, and at 45 C, although it is unstable at 60 C.

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