TY - JOUR
T1 - Direct electrochemistry and intramolecular electron transfer of ascorbate oxidase confined on l-cysteine self-assembled gold electrode
AU - Patil, Bhushan
AU - Kobayashi, Yoshiki
AU - Fujikawa, Shigenori
AU - Okajima, Takeyoshi
AU - Mao, Lanqun
AU - Ohsaka, Takeo
N1 - Funding Information:
This research was financially supported by Grant-in-Aid for Scientific Research (A) (No. 19206079 ) to T. Ohsaka from the Ministry of Education, Culture, Sports, Science and Technology, Japan and Tokyo Institute of Technology Global COE Program for Energy Science. An International Program Associate fellowship to B. Patil from RIKEN, Japan is gratefully acknowledged.
PY - 2014/2
Y1 - 2014/2
N2 - A direct electrochemistry and intramolecular electron transfer of multicopper oxidases are of a great importance for the fabrication of these enzyme-based bioelectrochemical-devices. Ascorbate oxidase from Acremonium sp. (ASOM) has been successfully immobilized via a chemisorptive interaction on the l-cysteine self-assembled monolayer modified gold electrode (cys-SAM/AuE). Thermodynamics and kinetics of adsorption of ASOM on the cys-SAM/AuE were studied using cyclic voltammetry.A well-defined redox wave centered at 166±3mV (vs. AgAgClKCl(sat.)) was observed in 5.0mM phosphate buffer solution (pH7.0) at the fabricated ASOM electrode, abbreviated as ASOM/cys-SAM/AuE, confirming a direct electrochemistry, i.e., a direct electron transfer (DET) between ASOM and cys-SAM/AuE. The direct electrochemistry of ASOM was further confirmed by taking into account the chemical oxidation of ascorbic acid (AA) by O2 via an intramolecular electron transfer in the ASOM as well as the electrocatalytic oxidation of AA at the ASOM/cys-SAM/AuE.Thermodynamics and kinetics of the adsorption of ASOM on the cys-SAM/AuE have been elaborated along with its direct electron transfer at the modified electrodes on the basis of its intramolecular electron transfer and electrocatalytic activity towards ascorbic acid oxidation and O2 reduction. ASOM saturated surface area was obtained as 2.41×10-11molcm-2 with the apparent adsorption coefficient of 1.63×106Lmol-1. The ASOM confined on the cys-SAM/AuE possesses its essential enzymatic function.
AB - A direct electrochemistry and intramolecular electron transfer of multicopper oxidases are of a great importance for the fabrication of these enzyme-based bioelectrochemical-devices. Ascorbate oxidase from Acremonium sp. (ASOM) has been successfully immobilized via a chemisorptive interaction on the l-cysteine self-assembled monolayer modified gold electrode (cys-SAM/AuE). Thermodynamics and kinetics of adsorption of ASOM on the cys-SAM/AuE were studied using cyclic voltammetry.A well-defined redox wave centered at 166±3mV (vs. AgAgClKCl(sat.)) was observed in 5.0mM phosphate buffer solution (pH7.0) at the fabricated ASOM electrode, abbreviated as ASOM/cys-SAM/AuE, confirming a direct electrochemistry, i.e., a direct electron transfer (DET) between ASOM and cys-SAM/AuE. The direct electrochemistry of ASOM was further confirmed by taking into account the chemical oxidation of ascorbic acid (AA) by O2 via an intramolecular electron transfer in the ASOM as well as the electrocatalytic oxidation of AA at the ASOM/cys-SAM/AuE.Thermodynamics and kinetics of the adsorption of ASOM on the cys-SAM/AuE have been elaborated along with its direct electron transfer at the modified electrodes on the basis of its intramolecular electron transfer and electrocatalytic activity towards ascorbic acid oxidation and O2 reduction. ASOM saturated surface area was obtained as 2.41×10-11molcm-2 with the apparent adsorption coefficient of 1.63×106Lmol-1. The ASOM confined on the cys-SAM/AuE possesses its essential enzymatic function.
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U2 - 10.1016/j.bioelechem.2013.10.005
DO - 10.1016/j.bioelechem.2013.10.005
M3 - Article
C2 - 24189123
AN - SCOPUS:84887145439
SN - 1567-5394
VL - 95
SP - 15
EP - 22
JO - Bioelectrochemistry
JF - Bioelectrochemistry
ER -