Direct electrochemistry of Rhodococcus opacus hydrogenase for the catalysis of NAD+ reduction - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Electroanalytical Chemistry Année : 1996

Direct electrochemistry of Rhodococcus opacus hydrogenase for the catalysis of NAD+ reduction

Résumé

The catalysis of NAD+ reduction by Rhodococcus opacus hydrogenase was investigated by spectroelectrochemistry in a thin layer cell on a platinum electrode. The NADH formation rates were significantly higher than those obtained with the hydrogenase of Alcaligenes eutrophus which has previously been identified as a good catalyst of this electrochemical reduction. As a consequence, for the first time to our knowledge, a well-identified current peak which corresponded to NAD+ reduction was observed on the voltammograms obtained with a platinum cathode. Thanks to the efficiency of this catalysis, it has been possible to improve the understanding of the mechanism. A two-step mechanism was assumed, according to the structure of the hydrogenase which is composed of two dimers with distinct hydrogenase and diaphorase activity. At high potentials (above −0.66 V (SCE)) only the diaphorase dimer was reduced by direct electron transfer from the electrode, without intervention of any hydrogen intermediate. For more negative potentials, a reduced hydrogen species adsorbed on the electrode surface was involved in the mechanism. In this case, catalysis followed a more classic catalytic pathway via the hydrogenase dimer and an intramolecular electron transfer to the diaphorase dimer, which reduced NAD+.

Dates et versions

hal-04347335 , version 1 (15-12-2023)

Identifiants

Citer

Pierre Gros, Christiane Zaborosch, Hans Schlegel, Alain Bergel. Direct electrochemistry of Rhodococcus opacus hydrogenase for the catalysis of NAD+ reduction. Journal of Electroanalytical Chemistry, 1996, 405 (1-2), pp.189-195. ⟨10.1016/0022-0728(95)04419-1⟩. ⟨hal-04347335⟩
8 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More