Biochemical properties of extracellular protease from Staphylococcus carnosus RT6 isolated from Harbin dry sausages, and its hydrolysis of meat proteins

The characteristics of the extracellular protease, produced by Staphylococcus carnosus RT6 isolated from Harbin dry sausages, and its hydrolysis of meat proteins were investigated. The protease was purified by ammonium sulfate, ion exchange, and gel filtration chromatography to obtain a 20.0 kDa extracellular protease. The protease reached maximal activity at pH 9.0 and 50 degrees C and was stable at pH 7.0 to 11.0 and 20 to 40 degrees C. Its protease activity was easily inhibited in the presence of Zn2+, Fe2+, and Fe3+. The enzymatic characterization of the protease revealed a V-max 49.50 U/ml center dot min, K-m 8.19 mg/ml, and the half-life = 28.06 min, Delta H*(d) = 114.11 kJ/mol, Delta G*(d) = 89.24 kJ/mol, and Delta S*(d) = 77.00 J/mol center dot K at 50 degrees C. In addition, the protease hydrolyzed meat protein into small particles and produced soluble peptides. This study provides a basis for understanding the biochemical characteristics of the S. carnosus RT6 protease and its future application for fermented meat products.