1. Redox-triggered events in cytochrome c nitrite reductase.
- Author
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Gwyer JD, Angove HC, Richardson DJ, and Butt JN
- Subjects
- Coated Materials, Biocompatible analysis, Coated Materials, Biocompatible chemistry, Cytochromes a1 antagonists & inhibitors, Cytochromes c1 antagonists & inhibitors, Enzyme Activation, Enzyme Inhibitors chemistry, Enzyme Stability, Enzymes, Immobilized analysis, Enzymes, Immobilized antagonists & inhibitors, Enzymes, Immobilized chemistry, Escherichia coli enzymology, Nitrate Reductases antagonists & inhibitors, Oxidation-Reduction, Substrate Specificity, Cyanides chemistry, Cytochromes a1 analysis, Cytochromes a1 chemistry, Cytochromes c1 analysis, Cytochromes c1 chemistry, Electrochemistry methods, Heme chemistry, Hydroxylamine chemistry, Nitrate Reductases analysis, Nitrate Reductases chemistry, Nitrites chemistry
- Abstract
Escherichia coli cytochrome c nitrite reductase is a homodimeric enzyme whose 10 heme centres range in reduction potential from ca. -30 to -320 mV. Protein film voltammetry (PFV) was performed to assess how the reactivity of the enzyme towards a number of small molecules was influenced by heme oxidation state. The experimental approach provided a high-resolution description of activity across the electrochemical potential domain by virtue of the fact that the enzyme sample was under the precise potential control of an electrode at all times. The current potential profiles displayed by nitrite reductase revealed that heme oxidation state has a profound, and often unanticipated, effect on the interactions with substrate molecules, nitrite and hydroxylamine, as well as the inhibitor, cyanide. Thus, PFV provides a powerful route to define redox-triggered events in this complex multi-centred redox enzyme.
- Published
- 2004
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