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Purification and characterization of a H2O2-tolerant alkaline protease from Bacillus sp. ZJ1502, a newly isolated strain from fermented bean curd
- Yu, Ping, Huang, Xingxing, Ren, Qian, Wang, Xinxin
- Food chemistry 2019 v.274 pp. 510-517
- Bacillus (bacteria), EDTA (chelating agent), butanol, casein, ethanol, hydrogen peroxide, manganese, molecular weight, pH, polyacrylamide gel electrophoresis, polysorbates, proteinases, temperature, tofu
- Alkaline protease was purified from Bacillus sp. ZJ1502 isolated from fermented bean curd and its enzymatic properties were investigated. The final purification fold and specific activity were 18.6 and 30,230 U/mg, respectively. The molecular weight was 14 kDa by SDS-PAGE. The optimal pH and temperature were 10.0 and 40 °C, respectively. Alkaline protease showed high stability at pH 9–11. Mn²⁺ and Tween-80 improved its activity by 22% and 31%, respectively, while SDS, CMC and EDTA respectively inhibited its activity by 33%, 47% and 22%. Alkaline protease exhibited poor tolerance to n-butyl alcohol and ethanol, but showed resistance to H2O2. 29.8% of the original activity was still retained after 0.5 M H2O2 treatment for 3 min. The Km and Vmax values of this enzyme towards casein were 16.7 mg/ml and 14.7 µg/(min·ml), respectively. This study provides a basis for understanding enzymatic properties of Bacillus sp. ZJ1502 alkaline protease.