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Investigations by Protein Film Electrochemistry of Alternative Reactions of Nickel-Containing Carbon Monoxide Dehydrogenase

Author:
Wang, Vincent C.-C., Islam, Shams T. A., Can, Mehmet, Ragsdale, Stephen W., Armstrong, Fraser A.
Source:
The Journal of physical chemistry 2015 v.119 no.43 pp. 13690-13697
ISSN:
1520-5207
Subject:
carbon dioxide, carbon electrodes, carbon monoxide, cyanides, electrochemistry, enzymes, formates, hydrogen, nitrous oxide, oxidation, oxygen, physical chemistry, prediction
Abstract:
Protein film electrochemistry has been used to investigate reactions of highly active nickel-containing carbon monoxide dehydrogenases (CODHs). When attached to a pyrolytic graphite electrode, these enzymes behave as reversible electrocatalysts, displaying CO₂ reduction or CO oxidation at minimal overpotential. The O₂ sensitivity of CODH is suppressed by adding cyanide, a reversible inhibitor of CO oxidation, or by raising the electrode potential. Reduction of N₂O, isoelectronic with CO₂, is catalyzed by CODH, but the reaction is sluggish, despite a large overpotential, and results in inactivation. Production of H₂ and formate under highly reducing conditions is consistent with calculations predicting that a nickel-hydrido species might be formed, but the very low rates suggest that such a species is not on the main catalytic pathway.
Agid:
5608302