Catalytic voltammetry of the molybdoenzyme sulfite dehydrogenase from sinorhizobium meliloti

Kalimuthu, Palraj, Kappler, Ulrike and Bernhardt, Paul V. (2014) Catalytic voltammetry of the molybdoenzyme sulfite dehydrogenase from sinorhizobium meliloti. Journal of Physical Chemistry B, 118 25: 7091-7099. doi:10.1021/jp503963z

Author Kalimuthu, Palraj
Kappler, Ulrike
Bernhardt, Paul V.
Title Catalytic voltammetry of the molybdoenzyme sulfite dehydrogenase from sinorhizobium meliloti
Journal name Journal of Physical Chemistry B   Check publisher's open access policy
ISSN 1520-6106
Publication date 2014-06-26
Year available 2014
Sub-type Article (original research)
DOI 10.1021/jp503963z
Open Access Status Not yet assessed
Volume 118
Issue 25
Start page 7091
End page 7099
Total pages 9
Place of publication Washington, DC United States
Publisher American Chemical Society
Language eng
Abstract Sulfite dehydrogenase from the soil bacterium Sinorhizobium meliloti (SorT) is a periplasmic, homodimeric molybdoenzyme with a molecular mass of 78 kDa. It differs from most other well studied sulfite oxidizing enzymes, as it bears no heme cofactor. SorT does not readily reduce ferrous horse heart cytochrome c which is the preferred electron acceptor for vertebrate sulfite oxidases. In the present study, ferrocene methanol (FM) (in its oxidized ferrocenium form) was utilized as an artificial electron acceptor for the catalytic SorT sulfite oxidation reaction. Cyclic voltammetry of FM was used to generate the active form of the mediator at the electrode surface. The FM-mediated catalytic sulfite oxidation by SorT was investigated by two different voltammetric methods, namely, (i) SorT freely diffusing in solution and (ii) SorT confined to a thin layer at the electrode surface by a semipermeable dialysis membrane. A single set of rate and equilibrium constants was used to simulate the catalytic voltammograms performed under different sweep rates and with various concentrations of sulfite and FM which provides new insights into the kinetics of the SorT catalytic mechanism. Further, we were able to model the role of the dialysis membrane in the kinetics of the overall catalytic system.
Keyword Chemistry, Physical
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP120101465
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Chemistry and Molecular Biosciences
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