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Direct electron transfer from graphite and functionalized gold electrodes to T1 and T2/T3 copper centers of bilirubin oxidase

Ramirez, Pablo; Mano, Nicolas; Andreu, Rafael; Ruzgas, Tautgirdas LU ; Heller, Adam; Gorton, Lo LU and Shleev, Sergey LU (2008) In Biochimica et Biophysica Acta - Bioenergetics 1777(10). p.1364-1369
Abstract
Direct electron transfer (DET) from bare spectrographic graphite (SPGE) or 3-mercaptopropionic acid-modified gold (MPA-gold) electrodes to Trachyderma tsunodae bilirubin oxidase (BOD) was studied under anaerobic and aerobic conditions by cyclic voltammetry and chronoamperometry. On cyclic voltammograms nonturnover Faradaic signals with midpoint potentials of about 700 mV and 400 mV were clearly observed corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively. The immobilized BOD was differently oriented on the two electrodes and its catalysis of O-2-electroreduction was also massively different. On SPGE, where most of the enzyme was oriented with the T1 copper site proximal to the carbon with... (More)
Direct electron transfer (DET) from bare spectrographic graphite (SPGE) or 3-mercaptopropionic acid-modified gold (MPA-gold) electrodes to Trachyderma tsunodae bilirubin oxidase (BOD) was studied under anaerobic and aerobic conditions by cyclic voltammetry and chronoamperometry. On cyclic voltammograms nonturnover Faradaic signals with midpoint potentials of about 700 mV and 400 mV were clearly observed corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively. The immobilized BOD was differently oriented on the two electrodes and its catalysis of O-2-electroreduction was also massively different. On SPGE, where most of the enzyme was oriented with the T1 copper site proximal to the carbon with a quite slow ET process, well-pronounced DET-bioelectroreduction of O-2 was observed, starting already at > 700 mV vs. NHE. In contrast, on MPA-gold most of the enzyme was oriented with its T2/T3 copper cluster proximal to the metal. Indeed, there was little DET-based catalysis of O-2-electroreduction, even though the ET between the MPA-gold and the T2/T3 copper cluster of BOD was similar to that observed for the T1 site at SPGE. When BOD actively catalyzes the O-2-electroreduction, the redox potential of its T1 site is 690 mV vs. NHE and that of one of its T2/T3 copper centers is 390 mV vs. NHE. The redox potential of the T2/T3 copper cluster of a resting form of BOD is suggested to be about 360 mV vs. NHE. These values, combined with the observed biocatalytic behavior, strongly suggest an uphill intra-molecular electron transfer from the T1 site to the T2/T3 cluster during the catalytic turnover of the enzyme. (C) 2008 Elsevier B.V. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
transfer kinetics, Electron, O-2-electroreduction, Bilirubin oxidase, Bioelectrocatalysis
in
Biochimica et Biophysica Acta - Bioenergetics
volume
1777
issue
10
pages
1364 - 1369
publisher
Elsevier
external identifiers
  • wos:000260284300015
  • scopus:52949143475
ISSN
0005-2728
DOI
10.1016/j.bbabio.2008.06.010
language
English
LU publication?
yes
id
9fb8fb1e-7cc1-4161-8e44-1b58ef86f6e7 (old id 1285005)
date added to LUP
2009-02-06 11:13:58
date last changed
2017-07-02 03:52:53
@article{9fb8fb1e-7cc1-4161-8e44-1b58ef86f6e7,
  abstract     = {Direct electron transfer (DET) from bare spectrographic graphite (SPGE) or 3-mercaptopropionic acid-modified gold (MPA-gold) electrodes to Trachyderma tsunodae bilirubin oxidase (BOD) was studied under anaerobic and aerobic conditions by cyclic voltammetry and chronoamperometry. On cyclic voltammograms nonturnover Faradaic signals with midpoint potentials of about 700 mV and 400 mV were clearly observed corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively. The immobilized BOD was differently oriented on the two electrodes and its catalysis of O-2-electroreduction was also massively different. On SPGE, where most of the enzyme was oriented with the T1 copper site proximal to the carbon with a quite slow ET process, well-pronounced DET-bioelectroreduction of O-2 was observed, starting already at > 700 mV vs. NHE. In contrast, on MPA-gold most of the enzyme was oriented with its T2/T3 copper cluster proximal to the metal. Indeed, there was little DET-based catalysis of O-2-electroreduction, even though the ET between the MPA-gold and the T2/T3 copper cluster of BOD was similar to that observed for the T1 site at SPGE. When BOD actively catalyzes the O-2-electroreduction, the redox potential of its T1 site is 690 mV vs. NHE and that of one of its T2/T3 copper centers is 390 mV vs. NHE. The redox potential of the T2/T3 copper cluster of a resting form of BOD is suggested to be about 360 mV vs. NHE. These values, combined with the observed biocatalytic behavior, strongly suggest an uphill intra-molecular electron transfer from the T1 site to the T2/T3 cluster during the catalytic turnover of the enzyme. (C) 2008 Elsevier B.V. All rights reserved.},
  author       = {Ramirez, Pablo and Mano, Nicolas and Andreu, Rafael and Ruzgas, Tautgirdas and Heller, Adam and Gorton, Lo and Shleev, Sergey},
  issn         = {0005-2728},
  keyword      = {transfer kinetics,Electron,O-2-electroreduction,Bilirubin oxidase,Bioelectrocatalysis},
  language     = {eng},
  number       = {10},
  pages        = {1364--1369},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta - Bioenergetics},
  title        = {Direct electron transfer from graphite and functionalized gold electrodes to T1 and T2/T3 copper centers of bilirubin oxidase},
  url          = {http://dx.doi.org/10.1016/j.bbabio.2008.06.010},
  volume       = {1777},
  year         = {2008},
}