catalytic mechanism for benzylamine oxidase from pig plasma. Stopped-flow kinetic studies

1. Ammonium ion is shown to decrease the rate constants for Schiff's base formation and formation of a reduced intermediate during the catalytic cycle of benzylamine oxidase from pig plasma. The rat constant for reoxidation of the reduced intermediate is also inhibited whilst the rate constant...

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Bibliographic Details
Published inEuropean journal of biochemistry Vol. 114; no. 1; pp. 139 - 144
Main Authors Yadav, K.D.S, Knowles, P.F
Format Journal Article
LanguageEnglish
Published England 01.01.1981
Subjects
Ammonium Chloride - pharmacology
animal physiology
Animals
Benzylamine Oxidase - blood
Catalysis
Dose-Response Relationship, Drug
Electron Spin Resonance Spectroscopy
Hydrogen Peroxide - metabolism
Kinetics
Monoamine Oxidase - blood
Oxidation-Reduction
Swine
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Summary:1. Ammonium ion is shown to decrease the rate constants for Schiff's base formation and formation of a reduced intermediate during the catalytic cycle of benzylamine oxidase from pig plasma. The rat constant for reoxidation of the reduced intermediate is also inhibited whilst the rate constant for conversion of the oxidised enzyme form back to native enzyme is stimulated by ammonium ion. 2. Ammonium ion changes the electron paramagnetic resonance spectrum of the cupric centres in the enzyme, indicating that ammonia binds to the copper. 3. A catalytic mechanism for benzylamine oxidase is proposed on the basis of these and other results. This mechanism includes a novel step in which a hydroxyl coordinated to copper acts as a nucleophyle to facilitate hydride ion transfer to oxygen during the reoxidation process.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0014-2956
1432-1033
DOI:10.1111/j.1432-1033.1981.tb06184.x