Effects of pH on the activity and structure of choline oxidase from Alcaligenes species.

Azadeh Hekmat; Ali Akbar Saboury; Ali Akbar Moosavi-Movahedi; Hedayatollah Ghourchian; Faizan Ahmad

doi:10.18388/abp.2008_3061

Effects of pH on the activity and structure of choline oxidase from Alcaligenes species.

Azadeh Hekmat Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.;
Ali Akbar Saboury
Ali Akbar Moosavi-Movahedi
Hedayatollah Ghourchian
Faizan Ahmad

DOI: https://doi.org/10.18388/abp.2008_3061

Abstract

A reversible effect of pH on the ionization of amino-acid residues at the active center of choline oxidase was observed near the optimum pH (8). Inactivation of choline oxidase took place in the pH ranges 3-6 and 9-11, in which irreversible changes in the structure occur leading to the enzyme inactivation. The first order rate constants of the enzyme's inactivation at various pH values were estimated for the irreversible changes. The Arrhenius analysis revealed no significant changes in the activation enthalpy, while an increase in the activation entropy reflected an increase in the conformational freedom.

Published

2008-09-04

Issue

Vol. 55 No. 3 (2008)

Section

Articles

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