Electrochemistry of cytochrome c at single carbon fiber electrodes

Arnold, David J.; Gerchario, Kim A.; Anderson, C. W.

doi:10.1016/0022-0728(84)80200-4

Cited by 13 publications

(3 citation statements)

References 12 publications

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“…The hydrophilic polished surface shows quasi-reversible electrochemistry with cytochrome c (Armstrong et al unpublished results). The observation of cytochrome c electrochemistry at single carbon-fibre electrodes (Arnold et al 1984) suggests a similar situation. In this case a cytochrome c faradaic response was observed only following electrochemical pre-cycling ( + 2-5 to -2-5 V vs. AgCl) of the electrode in buffer.…”

Section: (E) Rubredoxinmentioning

confidence: 81%

Reactions of electron-transfer proteins at electrodes

Allen

Hill

et al. 1985

Quart. Rev. Biophys.

148

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Studies of electron-transfer reactions of redox proteins have, in recent years, attracted widespread interest and attention. Progress has been evident from both physical and biological standpoints, with the increasing availability of three-dimensional structural data for many small electron-transfer proteins prompting a variety of systematic investigations (Isied, 1985). Most recently, attention has been directed towards questions concerning the elementary transfer of electrons between spatially remote redox sites, and the nature of protein–protein interactions which, for intermolecular processes, stabilize specific precursor complexes which may be optimally juxtaposed for electron-transfer. These and other issues, including the necessary reversibility of protein interfacial interactions and the dynamic properties of proteins as carriers of electrons in biological electron-transport systems, are now being addressed in the rapidly emerging field of direct (unmediated) protein electrochemistry. It is our intention in this article to discuss developments made in this area and highlight points which we believe to have the most bearing on our current understanding of diffusion-dominated, protein-mediated electron transport at electrode surfaces. First we shall outline some basic considerations which are best considered with reference to homogeneous systems.

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Section: (E) Rubredoxinmentioning

confidence: 81%

Reactions of electron-transfer proteins at electrodes

Allen

Hill

et al. 1985

Quart. Rev. Biophys.

148

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“…The effect of the electrode surface on the interaction with redox proteins is well known . For example, cytochrome c exhibits quasi-reversible behavior at metal oxide electrodes , and nonmetal electrodes, and its voltammetry is promoted at metal electrodes modified by the adsorption of various organic molecules. − The apparent difference in the behavior of the modified enzyme at the platinum and glassy carbon electrode surfaces could indicate that the enzyme is adsorbed in a different orientation. Our experience with free osmium complexes shows that they adsorb better on glassy carbon electrodes than platinum.…”

Section: Resultsmentioning

confidence: 99%

Covalent Attachment of Osmium Complexes to Glucose Oxidase and the Application of the Resulting Modified Enzyme in an Enzyme Switch Responsive to Glucose

1999

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Pyridine-based osmium complexes bearing either a carboxylate or aldehyde group were covalently attached to glucose oxidase and were shown to work as mediators for the reoxidation of the enzyme. For the complex containing the carboxylate group, the binding was made through carbodiimide coupling to the amine residues in the protein. For the complex containing the aldehyde group, the reductive coupling was carried out by condensation with the amino groups on the protein in the presence of sodium cyanoborohydride. Electrochemical studies show evidence for both intramolecular and intermolecular redox mediation for the electrochemical reoxidation of the modified glucose oxidases in the presence of glucose. The modified enzymes adsorbed on glassy carbon and platinum show different electrochemical responses for the two electrode materials, suggesting that orientation of the adsorbed enzyme is induced due to the interaction of the osmium complex with the different surfaces. Construction of enzyme switches based on these modified enzymes was carried out, and their responses were compared with those obtained using native glucose oxidase and a soluble redox mediator.

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“…The structure of glassy carbon [41] has been described as thin, tangled ribbons of graphite-like sheets and as such is isotropic. Electrodes constructed of this material exhibit the same surface chemical characteristics as edge-plane pyrolytic graphite and quasy-reversible electrochemistry has been observed with cytochrome c. Arnold et al [42] have reported cytochrome c electrochemistry at unmodified single carbon fibre electrodes. No mediators or promoters were required to facilitate electron transfer and the observation of faradaic electrochemistry using cyclic voltammetry.…”

Section: Other Surfaces For Direct Protein Electrochemistrymentioning

confidence: 71%

Direct and indirect electron transfer between electrodes and redox proteins

Frew¹,

Hill

1988

European Journal of Biochemistry

298

118

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The direct electrochemistry of redox proteins has been achieved at a variety of electrodes, including modified gold, pyrolytic graphite and metal oxides. Careful design of electrode surfaces and electrolyte conditions are required for the attainment of rapid and reversible protein-electrode interaction. The electron transfer reactions of more complex systems, such as redox enzymes, are now being examined. The 'well-behaved' electrochemistry of redox proteins can be usefully exploited by coupling the electrode reaction to enzymes for which the redox proteins act as cofactors. In systems where direct electron transfer is very slow, small electron carriers, or mediators, may be employed to enhance the rate of electron exchange with the electrode. The organometallic compound ferrocene and its derivatives have proved particularly effective in this role. A new generation of electrochemical biosensors employs ferrocene derivatives as mediators.Many of the fundamental processes in Nature rely upon the redox processes of constituent biomolecules. Cell respiration involves the stepwise oxidation of organic substrates via a cascade of redox reactions. In photosynthetic organisms, chains of electron carriers, for example, flavoproteins, ironsulphur proteins and cytochromes, participate in light-induced photosynthetic electron transport. The intrinsic mechanisms of electron transfer reactions, and the detailed role of the protein in aiding the electron transfer between redox centres, have become foci for extensive physical and biochemical investigations [l].Electrochemistry provides a powerful tool for examining electron transfer properties. The molecules of particular interest are redox-active proteins and enzymes. Although there have been many investigations of the electrochemical behaviour of the isolated and 'free' prosthetic groups [2, 31, the properties of the latter in an intact protein are so perturbed that to gain an understanding of their biological role, it is essential to have information on the behaviour of the proteins themselves.Only relatively recently has the feasibility of studying the electron transfer reactions of redox proteins at an electrode surface been viewed with any real optimism. Indeed, for many years it was thought that reversible, direct electron transfer (i. e. without mediation by small electron carriers) between electrodes and redox proteins was not possible. Several reasons were given: the slow rates of diffusion of these species were presumed to lead to greatly diminished faradaic currents; the 'buried' nature of the redox groups would make interaction with an electrode prohibitive for all but a few orientations of the protein at the electrode surface and proteins appeared to denature at the electrode-electrolyte interface. In fact, the early studies of protein electrochemistry were unlikely to succeed simply due to the type of electrodes used [4-61. Mercury was the favoured electrode material and, in such systems, adsorption phenomena play a predominant role with the possibility of confor...

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Electrochemistry of cytochrome c at single carbon fiber electrodes

Cited by 13 publications

References 12 publications

Reactions of electron-transfer proteins at electrodes

Reactions of electron-transfer proteins at electrodes

Covalent Attachment of Osmium Complexes to Glucose Oxidase and the Application of the Resulting Modified Enzyme in an Enzyme Switch Responsive to Glucose

Direct and indirect electron transfer between electrodes and redox proteins

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