722—The effect of pH on the temperature dependence of the redox potential of horse heart cytochrome c at a bis(4-pyridyl)disulfide-modified gold electrode

Taniguchi, Ikuo; Iseki, Masahiro; Eto, Takaki; Toyosawa, Kenji; Yamaguchi, Hiroko; Yasukouchi, Kazuo

doi:10.1016/0302-4598(84)87038-5

Cited by 63 publications

(30 citation statements)

References 29 publications

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“…2a, Tables 2, 3 and 4). Similar E°0 versus T profiles were previously observed for several cytochromes at alkaline pH values [33,[36][37][38][39]. The E°0 versus T plots for wave II for all the investigated proteins show invariably a monotonic linear increase of E°0 with increasing temperature (Fig.…”

Section: Resultssupporting

confidence: 84%

“…The presence of two T-dependent conformers was already observed for cytochromes c from various sources upon increasing pH from slightly acidic or neutral values, but the reason for this transition is not fully understood [33,36,37,39,[48][49][50]. It has been proposed that this thermal transition involves a conformer with a lower protonation number characterized by a reduced state stabilized on enthalpic bases.…”

Section: Discussionmentioning

confidence: 99%

“…Solvent reorganization effects, reduction-induced changes in the hydrogen bonding network within the hydration sphere of the cytochrome c and in protein flexibility are supposed to play the major role in determining the DS 0 rc values [4, 33, 36-38, 51, 52]. The negative DH 0 rc values, however, mostly arise from the stabilization of the ferroheme by ligand binding interactions and the hydrophobicity of the heme environment, but is also modulated by electrostatic interactions of the heme with protein surface and solution charges [4,33,[36][37][38][51][52][53]. The slight decrease in the E°0 values observed for the N ?…”

Section: Discussionmentioning

confidence: 99%

“…X LT transition are not available yet, direct interaction of urea molecules with the cytochrome c surface and substitution of water molecules at the protein-solvent interface probably play an important role in the compensative change of the thermodynamic parameters. The absence of perfect compensation is most likely related to the fact that the variations in reduction enthalpy depend also on changes in electrostatics at the metal site and the selective stabilization of the oxidized heme by the increasing solvent exposure [4,33,[36][37][38][51][52][53]. In the case of the N ?…”

Section: Discussionmentioning

confidence: 99%

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Redox thermodynamics of cytochromes c subjected to urea induced unfolding

et al. 2009

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The thermodynamics of the electron transfer (ET) process for beef heart and yeast cytochromes c and the Lys72Ala/Lys73Ala/Lys79Ala mutant of the latter species subjected to progressive urea-induced unfolding was determined electrochemically. The results indicate the presence of at least three protein forms which were assigned to a low-temperature and a high-temperature HisMet intermediate species and a bis-histidinate form (although the presence of a His-Lys form cannot be excluded). The much lower E°0 value of the bis-histidinate conformer as compared to His-Met ligated species is largely determined by the enthalpic contribution induced by axial ligand substitution. The biphasic E°0 versus T profile for the His-Met species is due to a difference in reduction entropy between the conformers at low and high temperatures. Enthalpy-entropy compensation phenomena for the reduction reaction at varying urea concentration for all the forms of the investigated cytochromes c were addressed and discussed.

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Section: Resultssupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Redox thermodynamics of cytochromes c subjected to urea induced unfolding

et al. 2009

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“…In order to check the possibility to use DPV at NEEs for trace determinations even of those analytes which are "difficult" to determine, a series of tests were performed in solutions containing the redox protein cytochrome c. Really, the electrochemistry of cyt c has been studied widely; however the usual procedure to obtain the protein electrochemistry signal is to add to the cyt c solution a suitable promoter (typically 4,4 -bipy [18,19] or 4,4 -dipirydil sulfide [20,21] or others [22,23]) or to use electrodes modified with polyanionic coatings or membranes [13,24]; in both cases the modifier interacts with the protein and orient it in a way which favors the electron transfer. A couple of examples showing the possibility to avoid the use of the promoter has been published.…”

Section: Differential Pulse Voltammetry With Nees For Trace Analysesmentioning

confidence: 99%

Voltammetry of redox analytes at trace concentrations with nanoelectrode ensembles

Moretto

Pepe

Ugo

2004

Talanta

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Medium and Temperature Effects on the Redox Chemistry of Cytochromec

Battistuzzi

Borsari

Sola

2001

Eur. J. Inorg. Chem.

113

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Cytochromes c (cytc) are ubiquitous heme-containing metalloproteins that shuttle electrons in a variety of electron-transport chains, most often central to the production of the chemical energy necessary for cell life. The reduction potential (E°Ј) of the Fe 3+/2+ couple is central to the physiological role of these species in that it influences the thermodynamic and kinetic features of electron-exchange reactions with redox partners. In the last two decades, voltammetric techniques exploiting the heterogeneous electron exchange between cytc and solid electrodes have proved to be particularly valuable for the determination of E°Ј values for these species and for characterizing the mechanistic and kinetic aspects of the redox process for the various cytc conformers under a variety of solution conditions. The understanding of how, and to what extent, different molecular factors control the E°Ј value in these species has been the subject of much debate. First coordination sphere effects on the heme iron and the interactions of the heme group with the surrounding polypeptide [a] Gianantonio Battistuzzi obtained his Ph.D. in Chemistry from the University of Modena (Italy) in 1996, under the supervision of Prof. M. Sola, working on the purification and the characterization of the solution behavior of electron-transfer metalloproteins. After a period in the laboratories of Professors H. Witzel and B. Krebs at the University of Münster, he held a postdoctoral position at the University of Modena, where he was appointed Assistant Professor of Inorganic Chemistry in 1999. His main research interest lies in the understanding of the molecular and solution factors influencing the thermodynamics of the reduction of electron-transfer metalloproteins, in particular cytochromes c and blue copper proteins, through a combination of electrochemical and spectroscopic techniques. Marco Borsari obtained his Ph.D. in Chemistry from the University of Modena (Italy) in 1992, working with Prof. G. Gavioli on the characterization of the electrochemical behavior of sulfur-containing organic molecules and the determination of the nature and stability of metal complexes in solution through voltammetric and polarographic techniques. In 1992, he was appointed Assistant Professor of Physical Chemistry at the University of Modena and Reggio Emilia (Italy) and started working on the electrochemistry of metalloproteins with Marco Sola. He also established collaborations with the groups of I. Bertini and H. B. Gray. His main research activity has been directed towards the study of the redox properties of electron-transport proteins and redox enzymes, with a particular focus on the thermodynamics of the electron-transfer processes in cytochromes, blue copper, and ironϪsulfur proteins. Marco Sola obtained his Ph.D. in Chemistry from the University of Parma (Italy) in 1987. Between 1985 and 1991 he was a member of the group of I. Bertini and C. Luchinat in Florence working on NMR of paramagnetic metalloproteins. He spent 1988 as a research associate at ...

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722—The effect of pH on the temperature dependence of the redox potential of horse heart cytochrome c at a bis(4-pyridyl)disulfide-modified gold electrode

Cited by 63 publications

References 29 publications

Redox thermodynamics of cytochromes c subjected to urea induced unfolding

Redox thermodynamics of cytochromes c subjected to urea induced unfolding

Voltammetry of redox analytes at trace concentrations with nanoelectrode ensembles

Medium and Temperature Effects on the Redox Chemistry of Cytochromec

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