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Properties of native and hydrophobic laccases immobilized in the liquid-crystalline cubic phase on electrodes

Nazaruk, Ewa; Michota, Agnieszka; Bukowska, Jolanta; Shleev, Sergey LU ; Gorton, Lo LU and Bilewicz, Renata (2007) In Journal of Biological Inorganic Chemistry 12(3). p.335-344
Abstract
Both native Trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic voltammetry and Raman spectroscopy. Native laccase immobilized in the monoolein cubic phase was characterized with resonance Raman spectroscopy, which demonstrated that the structure at the "blue" copper site of the protein remained intact. The diamond-type monoolein cubic phase prevents denaturation of enzymes on the electrode surface and provides contact of the enzyme with the electrode either directly or through the mediation by electroactive probes. Direct electron transfer for both laccases incorporated into a lyotropic liquid crystal was obtained under anaerobic conditions, whereas... (More)
Both native Trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic voltammetry and Raman spectroscopy. Native laccase immobilized in the monoolein cubic phase was characterized with resonance Raman spectroscopy, which demonstrated that the structure at the "blue" copper site of the protein remained intact. The diamond-type monoolein cubic phase prevents denaturation of enzymes on the electrode surface and provides contact of the enzyme with the electrode either directly or through the mediation by electroactive probes. Direct electron transfer for both laccases incorporated into a lyotropic liquid crystal was obtained under anaerobic conditions, whereas bioelectrocatalytic activity was shown only for the native enzyme. The differences in electrochemical behavior of native and hydrophobic laccase as well as possible mechanisms of direct and mediated electron transfers are discussed. The Michaelis constant for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS(2-)), K-M(app), and the maximal current, I-max, for the native enzyme immobilized onto the electrode were estimated to be 0.24 mM, and 5.3 mu A, respectively. The maximal current density and the efficiency of the catalysis, I (max)/K-M(app), were found to be 73 mu A cm(-2) and 208.2 mu A cm(-2) mM(-1), respectively, and indicated a high efficiency of oxygen electroreduction by the enzyme in the presence of ABTS(2-) in the cubic-phase environment. Rate constants were calculated to be 7.5 x 10(4) and 3.6 x 10(4) M-1 s(-1) for native and hydrophobic laccase, respectively. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diammonium salt, oxygen reduction, 2, 2'-azinobis(3-ethylbenzothiazoline-6-sulfonate), laccase, voltammetry
in
Journal of Biological Inorganic Chemistry
volume
12
issue
3
pages
335 - 344
publisher
Springer
external identifiers
  • wos:000245457700006
  • scopus:34147138970
ISSN
1432-1327
DOI
10.1007/s00775-006-0193-7
language
English
LU publication?
yes
id
06255b2d-2e82-40fd-8101-afb8beba1503 (old id 667517)
date added to LUP
2007-12-18 12:47:11
date last changed
2017-07-23 03:57:52
@article{06255b2d-2e82-40fd-8101-afb8beba1503,
  abstract     = {Both native Trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic voltammetry and Raman spectroscopy. Native laccase immobilized in the monoolein cubic phase was characterized with resonance Raman spectroscopy, which demonstrated that the structure at the "blue" copper site of the protein remained intact. The diamond-type monoolein cubic phase prevents denaturation of enzymes on the electrode surface and provides contact of the enzyme with the electrode either directly or through the mediation by electroactive probes. Direct electron transfer for both laccases incorporated into a lyotropic liquid crystal was obtained under anaerobic conditions, whereas bioelectrocatalytic activity was shown only for the native enzyme. The differences in electrochemical behavior of native and hydrophobic laccase as well as possible mechanisms of direct and mediated electron transfers are discussed. The Michaelis constant for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS(2-)), K-M(app), and the maximal current, I-max, for the native enzyme immobilized onto the electrode were estimated to be 0.24 mM, and 5.3 mu A, respectively. The maximal current density and the efficiency of the catalysis, I (max)/K-M(app), were found to be 73 mu A cm(-2) and 208.2 mu A cm(-2) mM(-1), respectively, and indicated a high efficiency of oxygen electroreduction by the enzyme in the presence of ABTS(2-) in the cubic-phase environment. Rate constants were calculated to be 7.5 x 10(4) and 3.6 x 10(4) M-1 s(-1) for native and hydrophobic laccase, respectively.},
  author       = {Nazaruk, Ewa and Michota, Agnieszka and Bukowska, Jolanta and Shleev, Sergey and Gorton, Lo and Bilewicz, Renata},
  issn         = {1432-1327},
  keyword      = {diammonium salt,oxygen reduction,2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate),laccase,voltammetry},
  language     = {eng},
  number       = {3},
  pages        = {335--344},
  publisher    = {Springer},
  series       = {Journal of Biological Inorganic Chemistry},
  title        = {Properties of native and hydrophobic laccases immobilized in the liquid-crystalline cubic phase on electrodes},
  url          = {http://dx.doi.org/10.1007/s00775-006-0193-7},
  volume       = {12},
  year         = {2007},
}