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Lookup NU author(s): Dr Magali Roger
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Chemical Society, 2019.
For re-use rights please refer to the publisher's terms and conditions.
Cytochrome c oxidases (CcOs) are the terminal enzymes in energy-converting chains of microorganisms, where they reduce oxygen into water. Their affinity for O2 makes them attractive biocatalysts for technological devices in which O2 concentration is limited, but the high overpotentials they display on electrodes severely limit their applicative use. Here, the CcO of the acidophilic bacterium Acidithiobacillus ferrooxidans is studied on various carbon materials by direct protein electrochemistry and mediated one with redox mediators either diffusing or co-immobilized at the electrode surface. The entrapment of the CcO in a network of hydrophobic carbon nanofibers permits a direct electrochemical communication between the enzyme and the electrode. We demonstrate that the CcO displays a μM affinity for O2 and reduces O2 at exceptionally high electrode potentials in the range of +700 to +540 mV vs NHE over a pH range of 4-6. The kinetics of interactions between the enzyme and its physiological partners are fully quantified. Based on these results, an electron transfer pathway allowing O2 reduction in the acidic metabolic chain is proposed.
Author(s): Wang X, Clement R, Roger M, Bauzan M, Mazurenko I, Poulpiquet A, Ilbert M, Lojou E
Publication type: Article
Publication status: Published
Journal: Journal of the American Chemical Society
Year: 2019
Volume: 141
Issue: 28
Pages: 11093-11102
Online publication date: 19/06/2019
Acceptance date: 02/04/2016
Date deposited: 02/09/2019
ISSN (print): 0002-7863
ISSN (electronic): 1520-5126
Publisher: American Chemical Society
URL: https://doi.org/10.1021/jacs.9b03268
DOI: 10.1021/jacs.9b03268
PubMed id: 31274287
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