KINETICS OF DEACTIVATION OF L-LYSINAMIDASE, L-AMINOACYLASE AND D-HYDANTOINASE

The partially purified enzyme preparations of L-lysinamidase, L-aminoacylase and D-hydantoinase were investigated with the aim of clarifying the mechanism of deactivation. It was established on the basis of kinetic and preparative investigations that the analyzed enzymes are transformed into kinetically different forms during the thermal deactivation process. The kinetic forms of L-lysinamidase and D-hydantoinase differ in their K(m) values, and those of L-aminoacylase in the activation energies of the hydrolysis reaction. The investigation not only shows the applicability of the formal deactivation mechanism suggested by Henley and Sadana (1985) but also reveals its physical meaning.