Protein Film Voltammetry Reveals Distinctive Fingerprints of Nitrite and Hydroxylamine Reduction by a Cytochrome c Nitrite Reductase

Angove, H. C., Cole, Jeffrey A, Richardson, David and Butt, Julea (2002) Protein Film Voltammetry Reveals Distinctive Fingerprints of Nitrite and Hydroxylamine Reduction by a Cytochrome c Nitrite Reductase. The Journal of Biological Chemistry, 277 (26). pp. 23374-23381. ISSN 1083-351X

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Abstract

The cytochrome c nitrite reductases perform a key step in the biological nitrogen cycle by catalyzing the six-electron reduction of nitrite to ammonium. Graphite electrodes painted with Escherichia coli cytochrome cnitrite reductase and placed in solutions containing nitrite (pH 7) exhibit large catalytic reduction currents during cyclic voltammetry at potentials below 0 V. These catalytic currents were not observed in the absence of cytochrome c nitrite reductase and were shown to originate from an enzyme film engaged in direct electron exchange with the electrode. The catalytic current-potential profiles observed on progression from substrate-limited to enzyme-limited nitrite reduction revealed a fingerprint of catalytic behavior distinct from that observed during hydroxylamine reduction, the latter being an alternative substrate for the enzyme that is reduced to ammonium in a two electron process. Cytochrome c nitrite reductase clearly interacts differently with these two substrates. However, similar features underlie the development of the voltammetric response with increasing nitrite or hydroxylamine concentration. These features are consistent with coordinated two-electron reduction of the active site and suggest that the mechanisms for reduction of both substrates are underpinned by common rate-defining processes.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
Faculty of Science > School of Biological Sciences
University of East Anglia > Faculty of Science > Research Groups > Biophysical Chemistry
University of East Anglia > Faculty of Science > Research Groups > Molecular Microbiology
University of East Anglia > Faculty of Science > Research Groups > Organisms and the Environment
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Depositing User: Rachel Smith
Date Deposited: 15 Feb 2011 13:22
Last Modified: 04 Sep 2018 14:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/21418
DOI: 10.1074/jbc.M200495200

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