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

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. (C) 1998 Elsevier Science B.V. All rights reserved.