[Kinetics and thermodynamics of the hydrolysis-synthesis reaction of acetyl-L-methionine catalyzed by acylase I from hog kidney].

The kinetics and thermodynamics of the equilibrium reaction of hydrolysis--synthesis of acetyl-L-methionine catalyzed by acylase I from hog kidney were studied. At high concentrations of the products (acetate ion and L-methionine) the acetyl-L-methionine hydrolysis does not proceed to completion but to the equilibrium position. The equilibrium constant of hydrolysis determined at the attained equilibrium in both directions, i.e. hydrolysis and synthesis, is equal to 3.6 +/- 0.4. Based on the initial rates of hydrolysis and synthesis, a kinetic pattern for the dependence of the reaction rate on concentration of the components of the system is proposed. Evidence for this kinetic pattern is supported by the Holden ratio and the coincidence of the kinetic parameters calculated from the total kinetic curves and the initial rates of hydrolysis and synthesis of acetyl-L-methionine.