Article

Science in China Series C: Life Sciences

, Volume 51, Issue 1, pp 52-59

Expression, purification, and characterization of a thermophilic neutral protease from Bacillus stearothermophilus in Bacillus subtilis

  • Zhang Min Affiliated withCollege of Engineering, Shenyang Agricultural UniversityCollege of Biotechnology, Tianjin University of Science and Technology
  • , Zhao Cong Affiliated withCollege of Biotechnology, Tianjin University of Science and Technology
  • , Du LianXiang Affiliated withCollege of Biotechnology, Tianjin University of Science and Technology
  • , Lu FuPing Affiliated withCollege of Biotechnology, Tianjin University of Science and Technology Email author 
  • , Gao Chen Affiliated withCollege of Life Science, Nankai University

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Abstract

The gene coding for a thermophilic neutral protease from Bacillus stearothermophilus was expressed in Bacillus subtilis DB104, under the control of the sacB gene promoter. This was followed by either the native signal peptide sequence of this protease or the signal peptide sequence of the sacB gene. The protease was purified 3.8-fold, with a specific activity of 16530 U mg−1. As analyzed by SDS-PAGE, the molecular mass of the expressed protease was about 35 kDa, and the optimal temperature and pH of the protease were 65°C and 7.5, respectively. Moreover, it still had about 80% activity after 1 h reaction at 65 °C.

Keywords

Bacillus subtilis thermophilic neutral protease expression purification characterization