[Effect of trypsin microenvironment on the rate constants of elementary stages of Nalpha-benzoyl-L-arginine ethyl ester hydrolysis].

The hydrolysis reaction of Nalpha-benzoyl-L-arginine ethyl ester catalyzed by trypsin from pig pancreas was comparatively studied in an aqueous buffer solution and in the system of reversed micelles of Aerosol OT in octane (pH 8.5) to determine the mechanisms of influence of the enzyme microenvironment on the rate constants of the elementary stages of the enzymatic reaction. The temperature dependences of the catalytic constant kcat and the rate constant of the second order kcat/Km (s, catalysis efficiency) allowed the determination of the rate constants and the activation energy of elementary stages of the enzymatic reaction. It was revealed that a decrease in the efficiency of catalytic action of trypsin in inverted mycelles in comparison with an aqueous solution is first of all determined by a decrease in the rate constant of formation of the enzyme-substrate complex k1. Possible mechanisms of the effect of the microenvironment on the elementary stages of catalytic action of the enzyme are discussed.