Catalytic electrochemistry of xanthine dehydrogenase

Kalimuthu, Palraj, Leimkuehler, Silke and Bernhardt, Paul V. (2012) Catalytic electrochemistry of xanthine dehydrogenase. Journal of Physical Chemistry B, 116 38: 11600-11607. doi:10.1021/jp307374z


Author Kalimuthu, Palraj
Leimkuehler, Silke
Bernhardt, Paul V.
Title Catalytic electrochemistry of xanthine dehydrogenase
Journal name Journal of Physical Chemistry B   Check publisher's open access policy
ISSN 1520-6106
1520-5207
Publication date 2012-09
Sub-type Article (original research)
DOI 10.1021/jp307374z
Volume 116
Issue 38
Start page 11600
End page 11607
Total pages 8
Place of publication Washington, DC, United States
Publisher American Chemical Society
Collection year 2013
Language eng
Formatted abstract
We report the mediated electrocatalytic voltammetry of the molybdoenzyme xanthine dehydrogenase (XDH) from Rhodobacter capsulatus at a thiol-modified Au electrode. The 2-electron acceptor N-methylphenazinium methanesulfonate (phenazine methosulfate, PMS) is an effective artificial electron transfer partner for XDH instead of its native electron acceptor NAD +. XDH catalyzes the oxidative hydroxylation of hypoxanthine to xanthine and xanthine to uric acid. Cyclic voltammetry was used to generate the active (oxidized) form of the mediator. Simulation of the catalytic voltammetry across a broad range of substrate and PMS concentrations at different sweep rates was achieved with the program DigiSim to yield a set of consistent rate and equilibrium constants that describe the catalytic system. This provides the first example of the mediated electrochemistry of a xanthine dehydrogenase (or oxidase) that is uncomplicated by interference from product oxidation. A remarkable two-step, sequential oxidation of hypoxanthine to uric acid via xanthine by XDH is observed.
Keyword Protein film voltammetry
Rhodobacter-capsulatus
Electron-transfer
Sulfite dehydrogenase
Molybdenum enzymes
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Chemistry and Molecular Biosciences
 
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