Studies on kinetic parameters and stability of aminoacylase in non-conventional media

Abstract Catalytic properties and conformational stability of aminoacylase ( N -acylamino acid amidohydrolase, EC 3.5.1.14) were studied in water– N , N -dimethylformamide (DMF) and water–dioxane solvent mixtures. Beside the prompt inhibition the solvents caused further inactivation during incubations. In the presence of 5% DMF content the inactivation proceeds with a well-measurable rate ( t 1/2 39 min), while in the case of 20% DMF the enzyme practically lost its starting activity during 50 min incubation ( t 1/2 13 min). The K m value of the enzyme increased about three times with increasing DMF concentrations up to about 2.6 M DMF, while the V max value decreased practically to zero in the same concentration range.