title: Investigations by Protein Film Electrochemistry of Alternative Reactions of Nickel-Containing Carbon Monoxide Dehydrogenase.
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.
authors.affiliation: Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford , South Parks Road, Oxford, OX1 3QR, U.K.
authors.forename: Vincent C-C
authors.initials: VC
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford , South Parks Road, Oxford, OX1 3QR, U.K.
authors.forename: Shams T A
authors.initials: ST
authors.lastname: Islam
authors.affiliation: Department of Biological Chemistry, University of Michigan , Ann Arbor, Michigan 48109-0606, United States.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Can
authors.affiliation: Department of Biological Chemistry, University of Michigan , Ann Arbor, Michigan 48109-0606, United States.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Ragsdale
authors.affiliation: Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford , South Parks Road, Oxford, OX1 3QR, U.K.
authors.forename: Fraser A
authors.initials: FA
authors.lastname: Armstrong
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D055162:Biocatalysis; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000378:metabolism; D009532:Nickel / Q000737:chemistry* / Q000378:metabolism; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D046950:Thermoanaerobacterium / Q000201:enzymology
chemical_list: D009097:Multienzyme Complexes; D006108:Graphite; D009532:Nickel; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase; D010100:Oxygen