Purification and Characterization of Two Novel Halotolerant Extracellular Proteases from<i>Bacillus subtilis</i>Strain FP-133
作者:Endang SETYORINI、Shinji TAKENAKA、Shuichiro MURAKAMI、Kenji AOKI
DOI:10.1271/bbb.70.433
日期:2006.1
Bacillus subtilis 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 Bacillus 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 Fe2+, 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.
从发酵鱼酱中分离出的枯草芽孢杆菌FP-133菌株合成了两种新型耐盐胞外蛋白酶(expro-I和expro-II),在浓度为0-20%(w/v)NaCl时表现出活性且稳定。每种蛋白酶都经过纯化,并进行了表征。纯化的expro-I是一种非碱性丝氨酸蛋白酶,最佳pH值为7.5,尽管大多数枯草芽孢杆菌菌株的丝氨酸蛋白酶在碱性条件下起作用。expro-I的分子质量为29 kDa。纯化的expro-II是一种金属蛋白酶,分子质量为34 kDa。它由Fe2+激活,而Fe2+从未被报道为细菌蛋白酶的激活剂。在浓度为7.5%(w/v)NaCl时,这两种蛋白酶更喜欢动物蛋白作为天然底物,而不是植物蛋白。此外,在盐水中,expro-I和II分别对明胶和酪蛋白表现出高催化活性。