The synthetic rate of dipeptide catalyzed by organic solvent-stable protease from Pseudomonas aeruginosa PST-01 in the presence of water-soluble organic solvents
ABSTRACT The initial synthetic rates of peptide Cbz–Arg–Leu–NH2 from Cbz–Arg and Leu–NH2 using PST-01 protease in the presence and absence of organic solvents were investigated under various conditions. The synthetic rates of Cbz–Arg–Leu–NH2 in the presence of 50% (v/v) methanol, 50% (v/v) N,N-dimethylformamide (DMF) and 60% (v/v) dimethyl sulfoxide (DMSO) were 1.6-, 2.4-, and 5.1-times higher than that in the absence of organic solvent, respectively. The PST-01 protease was not only stable in the presence of organic solvents but also exhibited high reaction rates in the presence of methanol, DMF, and DMSO. When the Cbz–Arg concentration was lower than 60 mM or the Leu–NH2 concentration was lower than 400 mM, the initial rates increased lineally with increase in their concentrations. However, the rates did not increase when the Leu–NH2 concentration was more than 500 mM. The optimum temperature and pH of the reaction were 40°C and 7.0, respectively.