Cyclic voltammetry and derivative cyclic voltabsorptometry of purified horse heart cytochrome c at tin-doped indium oxide optically transparent electrodes

Bowden, Edmond F.; Hawkridge, Fred M.; Chlebowski, J F; Bancroft, Eric E.; Thorpe, Colin; Blount, Henry N.

doi:10.1021/ja00390a041

Cited by 144 publications

(66 citation statements)

References 2 publications

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“…The details of the calculations are given elsewhere 41 . The obtained kº value is also consistent with bibliographic data reported for graphite and ITO electrodes 37,39 . 2.0x10 -6 3.0x10 -6 4.0x10 -6 5.0x10 -6 6.0x10 -6 j/A.cm…”

Section: Preparation Of Electrodessupporting

confidence: 91%

“…7). In other words, it appears a correlation between reversibility and concentration which has already been reported by other authors 37,55,57 . According to the literature, this behavior can be due to the affinity shown by cyt c to the surface of metal oxide electrodes 58 .…”

Section: Preparation Of Electrodessupporting

confidence: 83%

“…Two stock solutions were prepared as follows: value is in good agreement with literature data [36][37][38][39][40] . From ∆Ep we have determined the value of the standard heterogeneous rate constant for the electron transfer, kº, which amounts to 6.60×10 -4 cm s -1 .…”

Section: Preparation Of Electrodesmentioning

confidence: 63%

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Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

et al. 2014

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The direct electron transfer between indium-tin oxide electrodes (ITO) and cytochrome c encapsulated in different sol-gel silica networks was studied. Cyt c@silica modified electrodes were synthesized by a two-step encapsulation method mixing a phosphate buffer solution with dissolved cytochrome c and a silica sol prepared by the alcohol free sol-gel route. These modified electrodes were characterized by cyclic voltammetry, UV-visible spectroscopy and in situ UV-visible spectroelectrochemistry.The electrochemical response of encapsulated protein is influenced by the terminal groups of the silica pores. Cyt c does not present electrochemical response in conventional silica (hydroxyl terminated) or phenyl terminated silica. Direct electron transfer to encapsulated cytochrome c and ITO electrodes only takes place when the protein is encapsulated in methyl modified silica networks.

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Section: Preparation Of Electrodessupporting

confidence: 91%

Section: Preparation Of Electrodessupporting

confidence: 83%

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Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

et al. 2014

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“…Alternatively, these and other workers have taken the approach to do without promoters by developing special pretreatment procedures and experimental protocol for the use of bare electrodes with proteins, e.g. [ l , 2, 4-81, The point has been made that high purity of protein preparation is an essential factor in the reproducibility of responses on bare electrodes [9].The method of promoted bioelectrochemistry commonly has the advantage of high reproducibility, however, its relevance from a biochemical point of view may in instances be unclear, as data interpretation may be hampered when the Corrcspondmce to W. R. Hagen, Laboratorium voor Biochemie, Landbouwuniversiteit, Dreijenlaan 3, NL-6703 HA Wageningen, The Netherlands response is specifically determined by properties intrinsic to the promoter (vide iqfra). Unpromoted bioelectrochemistry on bare electrodes is usually more difficult to attain and the responses are frequently not stable over the time course of a typical electrochemical measurement.…”

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confidence: 99%

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confidence: 99%

Direct electron transfer of redox proteins at the bare glassy carbon electrode

Hagen¹

1989

European Journal of Biochemistry

146

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A simple system is presented for the microscale, direct voltammetry of redox proteins, typically 25 pg, in the absence of mediators and/or modifiers. The sample consists of a droplet of anaerobic solution laid onto an oversized disc of nitric-acid-pretreated glassy carbon as the working electrode. Very reproducible, Nernstian responses are obtained with horse heart cytochrome c. The midpoint potential Em (pH 7.0) is dependent on the ionic strength, ranging from +293 mV in 1 mM potassium phosphate to +266 mV in 0.1 M phosphate. At fixed buffer and cytochrome concentrations the magnitude of the voltammetric response is found to be independent of pH over six pH units around neutrality. It is suggested that the response of the present system is not complicated by pH-dependent properties of the electrode surface around physiological pH and, therefore, that the use of this system is practical in biochemically oriented studies. Direct, quasi-reversible responses have also been obtained at pH 7.0 (5 mM phosphate) from DesuEfovibrio vulgaris. Hildenborough strain, tetraheme cytochrome c3 (PI = 10.0 at 4°C; 3 x Em = -0.32 mV, Em = -0.26 V), and cytochrome c S s 3 (PI = 9.3; Em = +60 mV), and from Megasphaera elsdenii rubredoxin (PI 'v 3; Em = f 4 2 mV) and 2[4Fe-4S] ferredoxin (PI 'v 3; Em = -353 mV). The latter protein adsorbs onto the glassy carbon surface, thus forming a system with possible applications in the electrochemical study of ferredoxin-linked enzymes.Direct, unmediated bioelectrochemistry at solid electrodes has been developed over the last decade from an academic possibility to a potentially powerful method for mechanistic studies on redox proteins [l]. The methodological hows and whys appear to a considerable extent to have been established by now in studies employing small, electron-transferring proteins [2]. The first successful detection of electron transfer between a true enzyme and a solid electrode was recently reported [3].Essentially, two different approaches have been tried to achieve direct, (quasi-)reversible electrode responses of redox proteins. The group of Hill and coworkers has been at the forefront of developing efficient and, possibly, specific promoters of bioelectrochemistry and trying to understand their mechanisms of action on the molecular level [I, 21. The notion, promoter, here means any substance that does not take part in the electron transfer in the electrochemical potential range of interest, but rather maneuvers itself in a specific manner between the redox protein and the electrode surface (i.e. the kinetic formation of a heterogeneous trimeric complex) such as to promote reversible electron transfer. Alternatively, these and other workers have taken the approach to do without promoters by developing special pretreatment procedures and experimental protocol for the use of bare electrodes with proteins, e.g. [ l , 2, 4-81, The point has been made that high purity of protein preparation is an essential factor in the reproducibility of responses on bare electrodes [9].The method...

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Introduction to Electrochemically Active Biofilms

Beyenal

Babauta

2015

Biofilms in Bioelectrochemical Systems

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Cyclic voltammetry and derivative cyclic voltabsorptometry of purified horse heart cytochrome c at tin-doped indium oxide optically transparent electrodes

Cited by 144 publications

References 2 publications

Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

Direct electron transfer of redox proteins at the bare glassy carbon electrode

Introduction to Electrochemically Active Biofilms

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