Cloning, expression, and characterization of an alkaline protease, AprV, from Vibrio sp. DA1-1.

A novel alkaline protease (named AprV) gene from Vibrio sp. DA1-1 was cloned and expressed in Escherichia coli BL21 (DE3) pLysS. The sequence analysis showed the highest homology of 68% with the characterized protease from Alkalimonas collagenimarina AC40T. The recombinant AprV was purified with the molecular weight of 28 kDa. The optimum temperature and pH were determined to be 55 °C and 10.0, respectively. The enzyme activity was slightly enhanced by Ca2+, Mg2+, Zn2+, Ba2+, and, however, was highly inhibited by Sn2+ and EDTA. The AprV was stable in the presence of some surfactants and oxidizing agents, such as 1% Tween 20-80, 1% JFC-2, and 5% JFC-2. Casein was found to be the ideal substrate with specific activity of 1139 U/mg. Moreover, we found that AprV (10,000 U), together with commercial detergent, could completely remove the blood on the cotton. Furthermore, AprV also demonstrated dehairing activity on goat and bull skin. These results indicated that the alkaline protease AprV might be a potential candidate for applications in the detergent and leather industries.