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Polyethyleneimine as a Promoter Layer for the Immobilization of Cellobiose Dehydrogenase from Myriococcum thermophilum on Graphite Electrodes

Schulz, Christopher LU ; Ludwig, Roland and Gorton, Lo LU (2014) In Analytical Chemistry 86(9). p.4256-4263
Abstract
Cellobiose dehydrogenase (CDH) is a promising enzyme for the construction of biofuel cell anodes and biosensors capable of oxidizing aldoses as cellobiose as well as lactose and glucose and with the ability to connect to an electrode through a direct electron transfer mechanism. In the present study, we point out the beneficial effect of a premodification of spectrographic graphite electrodes with the polycation polyethyleneimine (PEI) prior to adsorption of CDH from Myriococcum thermophilum (MtCDH). The application of PEI shifts the pH optimum of the response of the MtCDH modified electrode from pH 5.5 to 8. The catalytic currents to lactose were increased up to 140 times, and the KMapp values were increased up to 9 times. The previously... (More)
Cellobiose dehydrogenase (CDH) is a promising enzyme for the construction of biofuel cell anodes and biosensors capable of oxidizing aldoses as cellobiose as well as lactose and glucose and with the ability to connect to an electrode through a direct electron transfer mechanism. In the present study, we point out the beneficial effect of a premodification of spectrographic graphite electrodes with the polycation polyethyleneimine (PEI) prior to adsorption of CDH from Myriococcum thermophilum (MtCDH). The application of PEI shifts the pH optimum of the response of the MtCDH modified electrode from pH 5.5 to 8. The catalytic currents to lactose were increased up to 140 times, and the KMapp values were increased up to 9 times. The previously investigated, beneficial effect of divalent cations on the activity of CDH was also present for graphite/PEI/MtCDH electrodes but was less pronounced. Polarization curves revealed a second unexpected catalytic wave for graphite/PEI/MtCDH electrodes especially pronounced at pH 8. Square wave voltammetric studies revealed the presence of an unknown redox functionality present at 192 mV vs Ag|AgCl (0.1 M KCl) at pH 8, probably originating from an oxidized adenosine derivative. Adenosine is a structural part of the flavin adenine dinucleotide (FAD) cofactor of the dehydrogenase domain of CDH. It is suggested that for some enzyme molecules FAD leaks out from the active site, adsorbs onto graphite, and is oxidized on the electrode surface into a product able to mediate the electron transfer between CDH and the electrode. PEI is suggested and discussed to act in several manners by (a) increasing the surface loading of the enzyme, (b) possibly increasing the electron transfer rate between CDH and the electrode, and (c) facilitating the creation or immobilization of redox active adenosine derivatives able to additionally mediate the electron transfer between CDH and the electrode. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Analytical Chemistry
volume
86
issue
9
pages
4256 - 4263
publisher
The American Chemical Society
external identifiers
  • pmid:24746119
  • wos:000335719900029
  • scopus:84899817424
ISSN
1520-6882
DOI
10.1021/ac403957t
language
English
LU publication?
yes
id
80d6e6ad-407d-48e9-8739-d974f21f918b (old id 4470552)
date added to LUP
2014-06-19 12:48:41
date last changed
2017-10-01 03:00:34
@article{80d6e6ad-407d-48e9-8739-d974f21f918b,
  abstract     = {Cellobiose dehydrogenase (CDH) is a promising enzyme for the construction of biofuel cell anodes and biosensors capable of oxidizing aldoses as cellobiose as well as lactose and glucose and with the ability to connect to an electrode through a direct electron transfer mechanism. In the present study, we point out the beneficial effect of a premodification of spectrographic graphite electrodes with the polycation polyethyleneimine (PEI) prior to adsorption of CDH from Myriococcum thermophilum (MtCDH). The application of PEI shifts the pH optimum of the response of the MtCDH modified electrode from pH 5.5 to 8. The catalytic currents to lactose were increased up to 140 times, and the KMapp values were increased up to 9 times. The previously investigated, beneficial effect of divalent cations on the activity of CDH was also present for graphite/PEI/MtCDH electrodes but was less pronounced. Polarization curves revealed a second unexpected catalytic wave for graphite/PEI/MtCDH electrodes especially pronounced at pH 8. Square wave voltammetric studies revealed the presence of an unknown redox functionality present at 192 mV vs Ag|AgCl (0.1 M KCl) at pH 8, probably originating from an oxidized adenosine derivative. Adenosine is a structural part of the flavin adenine dinucleotide (FAD) cofactor of the dehydrogenase domain of CDH. It is suggested that for some enzyme molecules FAD leaks out from the active site, adsorbs onto graphite, and is oxidized on the electrode surface into a product able to mediate the electron transfer between CDH and the electrode. PEI is suggested and discussed to act in several manners by (a) increasing the surface loading of the enzyme, (b) possibly increasing the electron transfer rate between CDH and the electrode, and (c) facilitating the creation or immobilization of redox active adenosine derivatives able to additionally mediate the electron transfer between CDH and the electrode.},
  author       = {Schulz, Christopher and Ludwig, Roland and Gorton, Lo},
  issn         = {1520-6882},
  language     = {eng},
  number       = {9},
  pages        = {4256--4263},
  publisher    = {The American Chemical Society},
  series       = {Analytical Chemistry},
  title        = {Polyethyleneimine as a Promoter Layer for the Immobilization of Cellobiose Dehydrogenase from Myriococcum thermophilum on Graphite Electrodes},
  url          = {http://dx.doi.org/10.1021/ac403957t},
  volume       = {86},
  year         = {2014},
}