Direct Electrochemistry of Bilirubin Oxidase from <i>Magnaporthe orizae</i> on Covalently‐Functionalized MWCNT for the Design of High‐Performance Oxygen‐Reducing Biocathodes

Gentil, Solène; Carrière, Marie; Cosnier, Serge; Gounel, Sébastien; Mano, Nicolas; Goff, Alan Le

doi:10.1002/chem.201800774

Cited by 29 publications

(29 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the first scan ( Figure 1A, black line) the voltammogram on the forward sweep is characterized by two hysteresis observed at~0.40 V and~0.1 V vs SCE, indicating an activation step at low potentials for the ORR. During the second scan the onset for O 2 reduction occurs at~0.5 V. The hysteresis obtained during the first scan suggests that many molecules of the enzyme in direct electron contact with the graphite electrode are not catalytically active in a redox state corresponding to the AR form of the enzyme [27,46,47]. Therefore, the AR form can be activated for O 2 catalysis, at low potential for the Cu sites that form the TNC.…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

Comparison of Direct and Mediated Electron Transfer for Bilirubin Oxidase from Myrothecium Verrucaria. Effects of Inhibitors and Temperature on the Oxygen Reduction Reaction

et al. 2019

View full text Add to dashboard Cite

One of the processes most studied in bioenergetic systems in recent years is the oxygen reduction reaction (ORR). An important challenge in bioelectrochemistry is to achieve this reaction under physiological conditions. In this study, we used bilirubin oxidase (BOD) from Myrothecium verrucaria, a subclass of multicopper oxidases (MCOs), to catalyse the ORR to water via four electrons in physiological conditions. The active site of BOD, the T2/T3 cluster, contains three Cu atoms classified as T2, T3α, and T3β depending on their spectroscopic characteristics. A fourth Cu atom; the T1 cluster acts as a relay of electrons to the T2/T3 cluster. Graphite electrodes were modified with BOD and the direct electron transfer (DET) to the enzyme, and the mediated electron transfer (MET) using an osmium polymer (OsP) as a redox mediator, were compared. As a result, an alternative resting (AR) form was observed in the catalytic cycle of BOD. In the absence and presence of the redox mediator, the AR direct reduction occurs through the trinuclear site (TNC) via T1, specifically activated at low potentials in which T2 and T3α of the TNC are reduced and T3β is oxidized. A comparative study between the DET and MET was conducted at various pH and temperatures, considering the influence of inhibitors like H2O2, F−, and Cl−. In the presence of H2O2 and F−, these bind to the TNC in a non-competitive reversible inhibition of O2. Instead; Cl− acts as a competitive inhibitor for the electron donor substrate and binds to the T1 site.

show abstract

Section: Electrochemical Characterizationmentioning

confidence: 99%

Comparison of Direct and Mediated Electron Transfer for Bilirubin Oxidase from Myrothecium Verrucaria. Effects of Inhibitors and Temperature on the Oxygen Reduction Reaction

et al. 2019

View full text Add to dashboard Cite

show abstract

“…As an illustration, recent works in our laboratory showed that the half life of a BOD-based bioelectrode incorporated in carbon felts was restricted to one week at room temperature 12 . Furthermore, for direct wiring of a redox enzyme on a conductive support, it is mandatory to allow an electron tunneling between the enzyme active site and the electrode, and to permit substrate access [13][14][15][16][17] . By varying the pH of BOD adsorption on a carbon nanotube (CNT) network, Mazurenko et al demonstrated that electrostatic interactions were driving the adsorption process in an orientation favoring either this direct wiring (direct electron transfer, DET), or a connection via a diffusing redox mediator (MET) 15 .…”

Section: Introductionmentioning

confidence: 99%

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

et al. 2018

View full text Add to dashboard Cite

Oxygen reduction reaction is the limiting step in fuel cells, and many works are in progress to find efficient cathode catalysts. Among them, bilirubin oxidases are copper-based enzymes that reduce oxygen into water with low overpotentials. The factors that ensure electrocatalytic efficiency of the enzyme in the immobilized state are not well understood, however. In this work, we use a multiple methodological approach on a wide range of pH for protein adsorption and for electrocatalysis, to demonstrate the effect of electrostatic interactions on the electrical wiring, dynamics and stability of a bilirubin oxidase adsorbed on self-assembled-monolayers on gold. We show on one hand that the global charge of the enzyme controls the loading on the interface, and that the specific activity of the immobilized enzyme decreases with the enzyme coverage. On the other hand, we show that the dipole moment of the protein and the charge in the vicinity of the Cu site acting as the entry point of electrons, drive the enzyme orientation. In case of weak electrostatic interactions, we demonstrate that local pH variation affects the 2 electron transfer rate as a result of protein mobility on the surface. On the contrary, stronger electrostatic interactions destabilize the protein structure and affect the stability of the catalytic signal. These data illustrate the interplay between immobilized protein dynamics and local environment that control the efficiency of bioelectrocatalysis.

show abstract

“…To obtain an efficient direct electron transfer, the orientation of BOD needs to be controlled in such a way that the active center T1 is close to the electrode surface . In the last decades, numerous strategies have been proposed to immobilize BOD on various electrodes allowing efficient DET . To name a few, DET was achieved by BOD adsorption on electrodes functionalized with carboxyl groups, or by pulse‐assisted techniques .…”

Section: Introductionmentioning

confidence: 99%

Rational Design of Enzyme‐Modified Electrodes for Optimized Bioelectrocatalytic Activity

et al. 2019

Self Cite

View full text Add to dashboard Cite

This contribution is dedicated to Prof. Lo Gorton on the occasion of his 70 th birthday in recognition of his outstanding contributions to the field of (bio)electrochemistry over several decadesThe immobilization of bilirubin oxidase (BOD) on macroporous gold electrodes for the optimization of bioelectrocatalytic activity is described. A bilirubin oxidase mutant S362C (cys-BOD) engineered with a cysteine residue located on purpose at the enzyme surface close to the T1 active center was used. It allows the attachment in one-step of a self-assembled monolayer of the enzyme to gold through a reaction between the thiol group of the cysteine residue and the metal surface. BOD immobilization of wild type and S362C mutant in macroporous gold electrodes allowed high retention of activity and perfect control of the overall BOD loading due to the fine-tuning of the macroporous structure. The macroporous arrangement together with the use of cys-BOD makes these rationally designed enzyme-modified electrodes very promising candidates for high-performance bioelectrocatalytic devices with improved activity and stability. long-term stability of cys-BODÀ Au is interpreted as the consequence of the covalent bond between the enzyme and the gold structure, thus avoiding enzyme leaching even after several days of incubation.

show abstract

Direct Electrochemistry of Bilirubin Oxidase from Magnaporthe orizae on Covalently‐Functionalized MWCNT for the Design of High‐Performance Oxygen‐Reducing Biocathodes

Cited by 29 publications

References 30 publications

Comparison of Direct and Mediated Electron Transfer for Bilirubin Oxidase from Myrothecium Verrucaria. Effects of Inhibitors and Temperature on the Oxygen Reduction Reaction

Comparison of Direct and Mediated Electron Transfer for Bilirubin Oxidase from Myrothecium Verrucaria. Effects of Inhibitors and Temperature on the Oxygen Reduction Reaction

Electrostatic-Driven Activity, Loading, Dynamics, and Stability of a Redox Enzyme on Functionalized-Gold Electrodes for Bioelectrocatalysis

Rational Design of Enzyme‐Modified Electrodes for Optimized Bioelectrocatalytic Activity

Contact Info

Product

Resources

About