Purification and Characterization of Two Novel Halotolerant Extracellular Proteases from Bacillus subtilis Strain FP-133
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<I>Bacillus subtilis</I> strain FP-133, isolated from a fermented fish paste, synthesized two novel halotolerant extracellular proteases (expro-I and expro-II), showing activity and stability at concentrations of 0–20% (w/v) NaCl. Each protease was purified to homogeneity and characterized. The purified expro-I was a non-alkaline serine protease with an optimum pH of 7.5, although most serine proteases from <I>Bacillus</I> strains act at the alkaline side. The molecular mass of expro-I was 29 kDa. The purified expro-II was a metalloprotease with a molecular mass of 34 kDa. It was activated by Fe<SUP>2+</SUP>, which has never been reported as a bacterial protease activator. At a concentration of 7.5% (w/v) NaCl, both proteases preferred animal proteins to vegetable proteins as natural substrates. In addition, under saline conditions, expro-I and II showed high catalytic activity toward gelatin and casein respectively.
- Agricultural and Biological Chemistry
Agricultural and Biological Chemistry 70(2), 433-440, 2006-02-23
Japan Society for Bioscience, Biotechnology, and Agrochemistry