13C kinetic isotope effects on the reaction of a flavin amine oxidase determined from whole molecule isotope effects

José R. Tormos, Marina B. Suarez, Paul F. Fitzpatrick

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

A large number of flavoproteins catalyze the oxidation of amines. Because of the importance of these enzymes in metabolism, their mechanisms have previously been studied using deuterium, nitrogen, and solvent isotope effects. While these results have been valuable for computational studies to distinguish among proposed mechanisms, a measure of the change at the reacting carbon has been lacking. We describe here the measurement of a 13C kinetic isotope effect for a representative amine oxidase, polyamine oxidase. The isotope effect was determined by analysis of the isotopic composition of the unlabeled substrate, N, N’-dibenzyl-1,4-diaminopropane, to obtain a pH-independent value of 1.025. The availability of a 13C isotope effect for flavoprotein-catalyzed amine oxidation provides the first measure of the change in bond order at the carbon involved in this carbon-hydrogen bond cleavage and will be of value to understanding the transition state structure for this class of enzymes.

Original languageEnglish (US)
Pages (from-to)115-119
Number of pages5
JournalArchives of Biochemistry and Biophysics
Volume612
DOIs
StatePublished - Dec 15 2016

Keywords

  • Dehydrogenase
  • Enzyme mechanisms
  • Flavoprotein
  • Polyamine oxidase

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology

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