Electrochemical evaluation of electron transfer kinetics of high and low redox potential laccases on gold electrode surface

Marco Frasconi, Harry Boer, Anu Koivula, Franco Mazzei (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

Laccases and other multicopper oxidases are reported to be able to carry out direct electron transfer reactions when immobilized onto electrode surface. This allows detailed research of their electron transfer mechanisms. We have recently characterized the kinetic properties of four laccases in homogenous solution and immobilized onto an electrode surface with respect to a set of different redox mediators. In this paper we report the direct electron transfer of four purified laccases from Trametes hirsuta (ThL), Trametes versicolor (TvL), Melanocarpus albomyces (r-MaL) and Rhus vernicifera (RvL), by trapping the proteins within an electrochemically inert polymer of tributylmethyl phosphonium chloride coating a gold electrode surface. In particular, we have characterized the steps involved in the laccases electron transfer mechanism as well as the factors limiting each step. During the voltammetric experiments, non-turnover Faradic signals with midpoint potential of about 790 and 400 mV were observed for high potential laccases, ThL and TvL, corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively, whereas low redox potential laccases r-MaL and RvL shown a redox couple with a midpoint potential around 400 mV. The electrocatalytic properties of these laccase modified electrodes for the reduction of oxygen have been evaluated demonstrating significative direct electron transfer kinetics. The biocatalytic activity of laccases was also monitored in the presence of a well known inhibitor, sodium azide. On the basis of the experimental results, a hypothesis about the electronic pathway for intramolecular electron transfer characterizing laccases has been proposed.
Original languageEnglish
Pages (from-to)817-827
Number of pages11
JournalElectrochimica Acta
Volume56
Issue number2
DOIs
Publication statusPublished - 2010
MoE publication typeA1 Journal article-refereed

Fingerprint

Laccase
Gold
Electrodes
Kinetics
Electrons
Oxidation-Reduction
Transfer Factor
Sodium Azide
Enzymes
Sodium
Proteins
Coatings
Oxygen
Oxidoreductases
Polymers

Keywords

  • Laccase
  • Direct electron transfer
  • Voltammetry
  • Gold electrode

Cite this

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abstract = "Laccases and other multicopper oxidases are reported to be able to carry out direct electron transfer reactions when immobilized onto electrode surface. This allows detailed research of their electron transfer mechanisms. We have recently characterized the kinetic properties of four laccases in homogenous solution and immobilized onto an electrode surface with respect to a set of different redox mediators. In this paper we report the direct electron transfer of four purified laccases from Trametes hirsuta (ThL), Trametes versicolor (TvL), Melanocarpus albomyces (r-MaL) and Rhus vernicifera (RvL), by trapping the proteins within an electrochemically inert polymer of tributylmethyl phosphonium chloride coating a gold electrode surface. In particular, we have characterized the steps involved in the laccases electron transfer mechanism as well as the factors limiting each step. During the voltammetric experiments, non-turnover Faradic signals with midpoint potential of about 790 and 400 mV were observed for high potential laccases, ThL and TvL, corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively, whereas low redox potential laccases r-MaL and RvL shown a redox couple with a midpoint potential around 400 mV. The electrocatalytic properties of these laccase modified electrodes for the reduction of oxygen have been evaluated demonstrating significative direct electron transfer kinetics. The biocatalytic activity of laccases was also monitored in the presence of a well known inhibitor, sodium azide. On the basis of the experimental results, a hypothesis about the electronic pathway for intramolecular electron transfer characterizing laccases has been proposed.",
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Electrochemical evaluation of electron transfer kinetics of high and low redox potential laccases on gold electrode surface. / Frasconi, Marco; Boer, Harry; Koivula, Anu; Mazzei, Franco (Corresponding Author).

In: Electrochimica Acta, Vol. 56, No. 2, 2010, p. 817-827.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Electrochemical evaluation of electron transfer kinetics of high and low redox potential laccases on gold electrode surface

AU - Frasconi, Marco

AU - Boer, Harry

AU - Koivula, Anu

AU - Mazzei, Franco

PY - 2010

Y1 - 2010

N2 - Laccases and other multicopper oxidases are reported to be able to carry out direct electron transfer reactions when immobilized onto electrode surface. This allows detailed research of their electron transfer mechanisms. We have recently characterized the kinetic properties of four laccases in homogenous solution and immobilized onto an electrode surface with respect to a set of different redox mediators. In this paper we report the direct electron transfer of four purified laccases from Trametes hirsuta (ThL), Trametes versicolor (TvL), Melanocarpus albomyces (r-MaL) and Rhus vernicifera (RvL), by trapping the proteins within an electrochemically inert polymer of tributylmethyl phosphonium chloride coating a gold electrode surface. In particular, we have characterized the steps involved in the laccases electron transfer mechanism as well as the factors limiting each step. During the voltammetric experiments, non-turnover Faradic signals with midpoint potential of about 790 and 400 mV were observed for high potential laccases, ThL and TvL, corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively, whereas low redox potential laccases r-MaL and RvL shown a redox couple with a midpoint potential around 400 mV. The electrocatalytic properties of these laccase modified electrodes for the reduction of oxygen have been evaluated demonstrating significative direct electron transfer kinetics. The biocatalytic activity of laccases was also monitored in the presence of a well known inhibitor, sodium azide. On the basis of the experimental results, a hypothesis about the electronic pathway for intramolecular electron transfer characterizing laccases has been proposed.

AB - Laccases and other multicopper oxidases are reported to be able to carry out direct electron transfer reactions when immobilized onto electrode surface. This allows detailed research of their electron transfer mechanisms. We have recently characterized the kinetic properties of four laccases in homogenous solution and immobilized onto an electrode surface with respect to a set of different redox mediators. In this paper we report the direct electron transfer of four purified laccases from Trametes hirsuta (ThL), Trametes versicolor (TvL), Melanocarpus albomyces (r-MaL) and Rhus vernicifera (RvL), by trapping the proteins within an electrochemically inert polymer of tributylmethyl phosphonium chloride coating a gold electrode surface. In particular, we have characterized the steps involved in the laccases electron transfer mechanism as well as the factors limiting each step. During the voltammetric experiments, non-turnover Faradic signals with midpoint potential of about 790 and 400 mV were observed for high potential laccases, ThL and TvL, corresponding to redox transformations of the T1 site and the T2/T3 cluster of the enzyme, respectively, whereas low redox potential laccases r-MaL and RvL shown a redox couple with a midpoint potential around 400 mV. The electrocatalytic properties of these laccase modified electrodes for the reduction of oxygen have been evaluated demonstrating significative direct electron transfer kinetics. The biocatalytic activity of laccases was also monitored in the presence of a well known inhibitor, sodium azide. On the basis of the experimental results, a hypothesis about the electronic pathway for intramolecular electron transfer characterizing laccases has been proposed.

KW - Laccase

KW - Direct electron transfer

KW - Voltammetry

KW - Gold electrode

U2 - 10.1016/j.electacta.2010.09.056

DO - 10.1016/j.electacta.2010.09.056

M3 - Article

VL - 56

SP - 817

EP - 827

JO - Electrochimica Acta

JF - Electrochimica Acta

SN - 0013-4686

IS - 2

ER -