The synthetic rate of dipeptide catalyzed by organic solvent-stable protease from Pseudomonas aeruginosa PST-01 in the presence of water-soluble organic solvents

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-dimethylformam ide (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 bu t 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 co ncentration was lower than 400 mM, the initial rates increased lineally wit h increase in their concentrations. However, the rates did not increase whe n the Leu-NH2 concentration was more than 500 mM. The optimum temperature a nd pH of the reaction were 40 degrees C and 7.0, respectively. (C) 2000 Els evier Science S.A. All rights reserved.