Studies on the stability of aminoacylase in some organic solvents

Abstract

Publisher Summary This chapter presents the recent results about the effects of dimethylformamide (DMF) and dioxane on the stability of aminoacylase. The effect of organic solvents on the stability of aminoacylase is studied both in native and immobilized form on a derivatized polyacrylamide-type bead support containing earboxyl groups. The enzyme was mixed with aqueous organic solvent solutions and the hydrolytic activity was measured within 15 sec and after longer incubation in 0.1 M potassium phosphate buffer (pH 7.0) containing 0.015 M N-acetyl-DL-methionine. It is found that in the ease of very short incubation in aqueous media with low concentrations of either solvent, the activity of aminoacylase is the same as that of untreated enzyme. However, during longer incubation the enzyme loses its activity and the rate of inactivation is increasing with the enhancement in the concentration of organic solvents. The chemical nature and polarity of DMF and dioxane are different. It is suggested that DMF is able to promote the dissociation of aminoacylase dimer and the unfolding processes of dimer and monomer are parallel. In the ease of dioxane it seems that the unfolding is faster than dissociation of dimer. Probably dioxane perturbes the hydrophobic core of the protein molecule.