[Study of E. coli penicillin amidase. The pH dependence of the equilibrium constant of the enzymatic hydrolysis of benzylpenicillin].
The equilibrium constant for penicillin amidase-catalyzed hydrolysis of benzylpenicillin(Keg =3.00 +/- 0.24 x 10(-3) M at pH 5.0) and the ionization constants for phenylacetic acid (PAA) and the amino groups of 6-aminopenicillanic acid (6-APA) were determined (4.20 and 4.60 under conditions of the kinetic experiments respectively). The experimental data at pH 6.0 satisfactorily correlated with the theoretical pH-dependence for Keg constructed according to the hypothesis that benzylpenicillin synthesis has a thermodynamic optimum at pH 4.4 equal to a half-sum of the pK values for the carboxylic and amino groups of the PAA and 6-APA respectively.
D000581:Amidohydrolases / Q000494:pharmacology*; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D008433:Mathematics; D010399:Penicillin Amidase / Q000494:pharmacology*; D010400:Penicillin G / Q000494:pharmacology*
D000581:Amidohydrolases; D010399:Penicillin Amidase; D010400:Penicillin G
Izuchenie penitsillinamidazy iz E. coli. pH-zavisimost' konstanty ravnovesiia fermentativnogo gidroliza benzilpenitsillina