Abstract

An extracellular endopeptidase from Bacillus cereus SH-7 was purified to homogeneity. The protease was most active at pH 8 and 40 C, respectively. The molecular mass of the protease was 40 kDa on SDS-PAGE, and 120 kDa by gel filtration, suggesting that the native enzyme is composed of three homogeneous subunits. The K_m and V_max values of the protease for N-succinyl-(Ala)_2-Pro-Phe-p-nitroanilide were 11.11 mM and 170 nmol/mg of protein/min, respectively. The protease was also identified as a metalloprotease. The bioactivity of the SH-7 protease will need further study in the future.

• Keywords: Bacillus cereus; metalloprotease; extracellular protease