In the experiments which aimed at unravelling electrochemical activity of laccase (Trametes hirsuta) redox centres, the enzyme has been adsorbed and its properties studied on the Au, IrO_x, or C₆₀-Pd electrode support in McIlvaine's buffer at pH»4.0, using cyclic (CV) and square wave (SW) voltammetry. In case of the Au electrode, only one redox couple was detected for laccase at ca. 0.30 V vs. SCE. However, a redox signal of this couple was split into three peaks at ca. 0.25 V, 0.40 V, and 0.55 V in the presence of catechol, i.e. one of the enzyme substrates that is not oxidized below 0.60 V. Presumably, these peaks, which increased after co-immobilization of Cu(II) ions within the enzyme film, corresponded to the oxidation of various copper centres of laccase. The heights of these peaks depended on both catechol and oxygen concentration in solution. It appeared that the laccase redox centres were inter-exchangeable when the enzyme was allowed to react with both reagents. For instance, after the addition of catechol, which is typically oxidized by laccase causing its reduction, the enzyme anodic peak at 0.40 V increased, while the anodic peak at 0.25 V decreased in the presence of oxygen. Moreover, catechol has been used as a mediator to study oxygen reduction catalysed by laccase. For these investigations, laccase was immobilized on a nanoparticulate iridium oxide (IrO_x) film and also on a Pd-containing C₆₀-Pd polymer film. The oxygen reduction potential on laccase-coated IrO_x was close to +0.1 V, compared to -0.1 V on Au. However, the reaction mechanism involving oxygen reduction to water rather than to hydrogen peroxide still remains to be proven. The most promising results have been obtained with the use of the C₆₀ polymer film. This film was prepared by CV electropolymerisation of C₆₀ in the presence of Pd(II) acetate trimer using a mixed solvent of 4:1 (v:v) toluene and acetonitrile. The C₆₀-Pd polymer features a pair of anodic and cathodic reversible CV peaks at ca. 0.25 V. In the absence of the catechol mediator, reduction of oxygen is enhanced only slightly by the adsorbed laccase. However, the addition of catechol, which reveals a quasi-reversible CV anodic and cathodic peak pair at ca. 0.35 V, results in the mediated reduction of oxygen by laccase at the reduction potential of this mediator.

• Legal notice:
  

  Copyright (c) Pielaszek Research, all rights reserved.
  The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
  In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/5187 must be provided.

1. The influence of CeO₂ on electrochemical performance of LiMn2O4.
2. Synthesis of nano-Li₄Ti₅O₁₂ decorated by silver nanoparticles as an anode material for lithium ion batteries
3. Structural and electrochemical studies on LiMn₂O₄ cathode material for LIBs coated with ceramic oxides
4. Safe nanomaterials of spinel structure for lithium-ion secondary batteries 
5. Piezomicrogravimetric chemosensor for determination of selected alkaloids with dedicated porphyrin polymer film as recognition unit
6. Molecularly imprinted polymer (MIP) chemosensors for surface plasmon resonance (SPR) and differerntial pulse voltammetry (DPV) determination of melamine
7. Electrochemically synthesized molecularly imprinted polymer for determination adenosine 5'-triphosphate (ATP)
8. Molecularly imprinted polymer based electrochemical sensors for flow injection determination of adrenaline
9. Detection of supercoiled and linear plasmid DNA
10. Inherently chiral conducting polymer electrodes 
11. Synthesis and studies on LiMn₂O₄/Carbon nanocomposites as a cathode materials for lithium ion batteries
12. Effect of deglycosylation of cellobiose dehydrogenase applied to 3rd generation biosensors and biofuel cells
13. Deglycosylation of glucose oxidase by PNGase F
14. Influence of metal cations on the turnover rate of cellobiose dehydrogenase
15. Electron transfer studies with different sugar oxidizing enzymes and osmium polymers to improve the current density
16. Gold nanoparticle-modified enzyme-based sugar and oxygen sensitive electrodes for biosensing and biofuel cell applications
17. Electrochemical communication between viable bacterial cells and flexible redox polymers
18. FIA detection of nicotine and cotinine using piezomicrogravimetric sensors with zinc porphyrin polymer films as their recognition elements
19. Structure-reactivity effects in electrocatalytic dioxygen reduction in aqueous solutions at electrodes coated by electrochemically synthesized molecularly imprinted polymers of a cobalt porphyrin diphenylamine derivative
20. A melamine acoustic chemosensor based on molecularly imprinted polymer film
21. The interactions between methylene blue and various types of DNA at screen-printed electrodes
22. An effective multipurpose building block for 3D electropolymerizations: 2,2’-bis(2,2’-bithiophene-5-yl)-3,3’-bi-1-benzothiophene
23. Direct electrochemistry of cellobiose dehydrogenase for applications in the third-generation biosensor and biofuel cell
24. Electrochemical Communication between Viable Bacterial Cells and Flexible Redox Polymers
25. Biosensing Applications Of Engineered Pyranose 2-oxidases Wired With Osmium Polymers
26. Preparation and selected properties of composites of the C₆₀-Pd conducting polymer and soluble single-wall carbon nanotubes
27. Development of a histamine acoustic sensor using film of molecularly imprinted polymer prepared by electrochemical co-polymerisation of bis(bithiophene) derivatives
28. Electrochemical polymerisation and electrocatalytic properties of structured selected aminophenyl derivatives of some metalloporphyrins
29. Incorporation of RuSe_x/C within nanostructural Ir matrices to enhance oxygen reduction
30. Anode and cathode reactions for biofuel cells based on direct electron transfer reactions between biological components and electrodes
31. Increasing Biosensor Sensitivity by Length Fractionated Single Walled Carbon Nanotubes
32. Polymer film-coated high electron mobility transistors, based on GaN heterostructures, as sensors for some benzene derivatives
33. Electrical Wiring of Living Bacillus subtilis Cells Using Flexible Osmium-Redox Polymers
34. Mass Spectrometric and in Situ ESR Vis-NIR Spectroelectrochemical Investigations of the Mechanism of the C₆₀ Electropolymerization in the Presence of Dioxygen in Aprotic Solvents
35. Composition, structure, surface topography, and electrochemical properties of electrophoretically deposited fullerene films
36. Formation and properties of donor-acceptor dyads of Zn porphyrins and C₆₀-imidazole adduct in the Langmuir and Langmuir-Blodgett Films
37. Electrochemical quartz crystal microbalance study of the avidin and albumin adsorption under flow injection analysis conditions
38. Oxygen electroreduction by fungal laccases - combination of electrochemical and spectral data
39. Wiring of whole living bacteria with osmium-redox polymers
40. Electrochemically formed fullerene-based polymers
41. The electrochemistry of a his-tagged microperoxidase assembled onto gold electrodes
42. Electron Transfer in Complex Two-cofactor-containing Enzymes at Alkanethiol-modified Gold Electrodes
43. Piezoelectric Microgravimetry for Determination of Some Biologically Important Compounds