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Electrochemical evidence of self-substrate inhibition as functions regulation for cellobiose dehydrogenase from Phanerochaete chrysosporium.

Stoica, Leonard LU ; Ruzgas, Tautgirdas LU and Gorton, Lo LU (2009) In Bioelectrochemistry 76(1-2). p.42-52
Abstract
The reaction mechanism of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium, adsorbed on graphite electrodes, was investigated by following its catalytic reaction with cellobiose registered in both direct and mediated electron transfer modes between the enzyme and the electrode. A wall-jet flow through amperometric cell housing the CDH-modified graphite electrode was connected to a single line flow injection system. In the present study, it is proven that cellobiose, at concentrations higher than 200 microM, competes for the reduced state of the FAD cofactor and it slows down the transfer of electrons to any 2e(-)/H(+) acceptors or further to the heme cofactor, via the internal electron transfer pathway. Based on and proven... (More)
The reaction mechanism of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium, adsorbed on graphite electrodes, was investigated by following its catalytic reaction with cellobiose registered in both direct and mediated electron transfer modes between the enzyme and the electrode. A wall-jet flow through amperometric cell housing the CDH-modified graphite electrode was connected to a single line flow injection system. In the present study, it is proven that cellobiose, at concentrations higher than 200 microM, competes for the reduced state of the FAD cofactor and it slows down the transfer of electrons to any 2e(-)/H(+) acceptors or further to the heme cofactor, via the internal electron transfer pathway. Based on and proven by electrochemical results, a kinetic model of substrate inhibition is proposed and supported by the agreement between simulation of plots and experimental data. The implications of this kinetic model, called pseudo-ping-pong mechanism, on the possible functions CDH are also discussed. The enzyme exhibits catalytic activity also for lactose, but in contrast to cellobiose, this sugar does not inhibit the enzyme. This suggests that even if some other substrates are coincidentally oxidized by CDH, however, they do not trigger all the possible natural functions of the enzyme. In this respect, cellobiose is regarded as the natural substrate of CDH. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Bioelectrochemistry
volume
76
issue
1-2
pages
42 - 52
publisher
Elsevier
external identifiers
  • wos:000270014400009
  • pmid:19640808
  • scopus:68549130449
ISSN
1878-562X
DOI
10.1016/j.bioelechem.2009.06.007
language
English
LU publication?
yes
id
691a7918-5d3b-47dc-af99-fda22a256af8 (old id 1470240)
date added to LUP
2009-09-08 13:41:25
date last changed
2017-09-24 03:29:48
@article{691a7918-5d3b-47dc-af99-fda22a256af8,
  abstract     = {The reaction mechanism of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium, adsorbed on graphite electrodes, was investigated by following its catalytic reaction with cellobiose registered in both direct and mediated electron transfer modes between the enzyme and the electrode. A wall-jet flow through amperometric cell housing the CDH-modified graphite electrode was connected to a single line flow injection system. In the present study, it is proven that cellobiose, at concentrations higher than 200 microM, competes for the reduced state of the FAD cofactor and it slows down the transfer of electrons to any 2e(-)/H(+) acceptors or further to the heme cofactor, via the internal electron transfer pathway. Based on and proven by electrochemical results, a kinetic model of substrate inhibition is proposed and supported by the agreement between simulation of plots and experimental data. The implications of this kinetic model, called pseudo-ping-pong mechanism, on the possible functions CDH are also discussed. The enzyme exhibits catalytic activity also for lactose, but in contrast to cellobiose, this sugar does not inhibit the enzyme. This suggests that even if some other substrates are coincidentally oxidized by CDH, however, they do not trigger all the possible natural functions of the enzyme. In this respect, cellobiose is regarded as the natural substrate of CDH.},
  author       = {Stoica, Leonard and Ruzgas, Tautgirdas and Gorton, Lo},
  issn         = {1878-562X},
  language     = {eng},
  number       = {1-2},
  pages        = {42--52},
  publisher    = {Elsevier},
  series       = {Bioelectrochemistry},
  title        = {Electrochemical evidence of self-substrate inhibition as functions regulation for cellobiose dehydrogenase from Phanerochaete chrysosporium.},
  url          = {http://dx.doi.org/10.1016/j.bioelechem.2009.06.007},
  volume       = {76},
  year         = {2009},
}