[Penicillin amidase from E. coli. Some physicochemical properties of the soluble enzyme].

Homogeneity of the enzyme was shown with the methods of gel filtration and disc electrophoresis. The molecular mass of penicillinamidase (PA) was determined. Sorption of PA by a carboxylic ion exchanger within a wide range of pH was studied. The values of pH in the ion exchanger phase under the conditions of the enzyme sorption were estimated. The ion exchange technique for determination of the isoelectric points of the proteins is described and the isoelectric point of PA is determined. It is proposed to use the method for estimation of close ionization constants of amphoteric an weak electrolites for interpretation of the bell-like pH dependence of kinetic and equilibrium parameters of the enzymatic reaction. The ionization constants of Michaelis complex of PA were evaluated. The activation energy of benzylpenicillin hydrolysis catalized by PA was determined.