Mediated spectroelectrochemical titration of proteins for redox potential measurements by a separator-less one-compartment bulk electrolysis method

Tsujimura, Seiya; Kuriyama, Atsushi; Fujieda, Nobutaka; Kano, Kenji; Ikeda, Tokuji

doi:10.1016/j.ab.2004.11.017

Cited by 67 publications

(50 citation statements)

References 26 publications

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“…2A, curve 2), coinciding with the proposed E T1 value of the enzyme [5,18]. The shape of the CV (an almost steady-state potential-current curve with a broad, feeble peak at A similar sigmoidal wave, although much less pronounced and visible only on the backgroundsubtracted CVs, was obtained at pH 7.0, in excellent agreement with our previously reported data [5].…”

Section: Trachyderma Tsunodae Boxsupporting

confidence: 89%

“…For example, E T1 values of high-redox-potential MCOs, e.g. fungal Lcs and BOxs, were measured by traditional potentiometric methods and found to be in the range of 0.65-0.78 V [6,18,19].…”

Section: Introductionmentioning

confidence: 99%

“…It is a highly similar to structures of other MCO and BOx contains a full complement of four copper ions per monomer, located in domains 1 and 3 [37,38]. In recent years, BOx from two sources, Myrothecium verrucaria and Trachyderma tsunodae BOx (MvBOx and TtBOx) have also been characterized electrochemically [4-6, 16, 19, 39, 40] and the redox potentials of the Cu-T1 sites (E T1 ) of both BOx were determined to be approximately 0.7 V using mediated and mediatorless cyclic voltammetry (CV) and redox titrations [5,18,19]. Therefore, MvBOx and TtBOx can be classified as high-redox-potential MCOs, which is an important property for biofuel cell applications.…”

Section: Introductionmentioning

confidence: 99%

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On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

et al. 2012

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The catalytic cycle of multicopper oxidases (MCOs) involves intramolecular electron transfer (IET) from the Cu‐T1 copper ion, which is the primary site of the one‐electron oxidations of the substrate, to the trinuclear copper cluster (TNC), which is the site of the four‐electron reduction of dioxygen to water. In this study we report a detailed characterization of the kinetic and electrochemical properties of bilirubin oxidase (BOx) – a member of the MCO family. The experimental results strongly indicate that under certain conditions, e.g. in alkaline solutions, the IET can be the rate‐limiting step in the BOx catalytic cycle. The data also suggest that one of the catalytically relevant intermediates (most likely characterized by an intermediate oxidation state of the TNC) formed during the catalytic cycle of BOx has a redox potential close to 0.4 V, indicating an uphill IET process from the T1 copper site (0.7 V) to the Cu‐T23. These suggestions are supported by calculations of the IET rate, based on the experimentally observed Gibbs free energy change and theoretical estimates of reorganization energy obtained by combined quantum and molecular mechanical (QM/MM) calculations.

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Section: Trachyderma Tsunodae Boxsupporting

confidence: 89%

“…For example, E T1 values of high-redox-potential MCOs, e.g. fungal Lcs and BOxs, were measured by traditional potentiometric methods and found to be in the range of 0.65-0.78 V [6,18,19].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

et al. 2012

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“…Oxidation-Reduction (Redox) Potential MeasurementsSpectroelectrochemical apparatus originally designed by Tsujimura et al (29) was modified to enable direct monitoring of the redox potential with a platinum indicator electrode. An anaerobic 1-cm path length cuvette was used with a septumcapped port for injection and a female ground glass joint at the top that fitted to a male joint of a micro combined electrode, EA 234 (Metrohm, Herisau, Switzerland).…”

Section: Methodsmentioning

confidence: 99%

Oxygen Binding and Redox Properties of the Heme in Soluble Guanylate Cyclase

Makino

Park

Obayashi

et al. 2011

Journal of Biological Chemistry

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Soluble guanylate cyclase is an NO-sensing hemoprotein that serves as a NO receptor in NO-mediated signaling pathways. It has been believed that this enzyme displays no measurable affinity for O 2 , thereby enabling the selective NO sensing in aerobic environments. Despite the physiological significance, the reactivity of the enzyme-heme for O 2 has not been examined in detail. In this paper we demonstrated that the high spin heme of the ferrous enzyme converted to a low spin oxyheme (Fe 2؉ -O 2 ) when frozen at 77 K in the presence of O 2 . The ligation of O 2 was confirmed by EPR analyses using cobalt-substituted enzyme. The oxy form was produced also under solution conditions at ؊7°C, with the extremely low affinity for O 2 . The low O 2 affinity was not caused by a distal steric protein effect and by rupture of the Fe 2؉ -proximal His bond as revealed by extended x-ray absorption fine structure. The midpoint potential of the enzyme-heme was ؉187 mV, which is the most positive among high spin protoheme-hemoproteins. This observation implies that the electron density of the ferrous heme iron is relatively low by comparison to those of other hemoproteins, presumably due to the weak Fe 2؉ -proximal His bond. Based on our results, we propose that the weak Fe 2؉ -proximal His bond is a key determinant for the low O 2 affinity of the heme moiety of soluble guanylate cyclase.

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“…In BOD, values between + 0.4 and + 0.5 V vs. Ag/AgCl are reported, thus they are somehow lower than observed in high potential LACs. [54][55][56][57] The variation in the potential values depends on the Cu coordination, nature of the ligands, geometry of the T1 Cu center, and the electrostatic and solvent effects. Potential values for T2 and T3 centers are more difficult to evaluate because of the many intermediates with different geometries and oxidation states that are generated in the course of O 2 reduction.…”

Section: Enzymes For O 2 Reductionmentioning

confidence: 99%

Biohydrogen for a New Generation of H₂/O₂ Biofuel Cells: A Sustainable Energy Perspective

et al. 2014

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Among sustainable alternatives to fossil fuel, proton exchange membrane fuel cells are promising devices that deliver electricity from hydrogen and oxygen, producing only water. The transformation of the fuel and oxidant however relies on rare‐metal catalysts. H2/O2 enzymatic biofuel cells thus emerge as sustainable biotechnological devices in which chemical catalysts are replaced by hydrogenases at the anode and multicopper oxidases at the cathode. This review discusses the recent breakthroughs and the limitations in all the components of H2/O2 biofuel cells: 1) Catalytic mechanisms involved in multicopper oxidases and hydrogenases, in addition to the new potential of enzymes from the biodiversity pool, which exhibit outstanding properties. 2) The molecular basis for oriented enzyme immobilization on the electrochemical interfaces as a prerequisite for a fast direct electron‐transfer rate. 3) The requirement for 3D networks to enhance current densities. 4) The production of H2 from biomass. 5) The history of H2/O2 biofuel cells and recent devices, which also highlights the remaining issues that will allow the use of such devices in low‐power applications.

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Mediated spectroelectrochemical titration of proteins for redox potential measurements by a separator-less one-compartment bulk electrolysis method

Cited by 67 publications

References 26 publications

On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

Oxygen Binding and Redox Properties of the Heme in Soluble Guanylate Cyclase

Biohydrogen for a New Generation of H₂/O₂ Biofuel Cells: A Sustainable Energy Perspective

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Mediated spectroelectrochemical titration of proteins for redox potential measurements by a separator-less one-compartment bulk electrolysis method

Cited by 67 publications

References 26 publications

On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

On the Possibility of Uphill Intramolecular Electron Transfer in Multicopper Oxidases: Electrochemical and Quantum Chemical Study of Bilirubin Oxidase

Oxygen Binding and Redox Properties of the Heme in Soluble Guanylate Cyclase

Biohydrogen for a New Generation of H2/O2 Biofuel Cells: A Sustainable Energy Perspective

Contact Info

Product

Resources

About

Biohydrogen for a New Generation of H₂/O₂ Biofuel Cells: A Sustainable Energy Perspective