jp5b02796_si_001.pdf (2.03 MB)
New Evidence for a Quasi-Simultaneous Proton-Coupled Two-Electron Transfer and Direct Wiring for Glucose Oxidase Captured by the Carbon Nanotube–Polymer Matrix
journal contribution
posted on 2015-07-09, 00:00 authored by Yiyang Liu, Tinatin
D. Dolidze, Sameer Singhal, Dimitri E. Khoshtariya, Jianjun WeiSystematic
cyclic voltammetry (CV) studies of glucose oxidase (GOx)
and its cofactor, flavine adenine dinucleotide (FAD), almost similarly
captured by the matrix of single-walled carbon nanotube and polymer
complex, in turn, deposited on GC electrodes have been performed.
The comparative analysis of kinetic data obtained for the FAD and
GOx specimens treated through the same Marcus theory-based algorithmic
procedure strongly suggests that the GOx species, notwithstanding
the deeply buried position of FAD, mechanistically behave virtually
in the same manner as isolated FADs (the operationally capable, nearly
intact structure of GOx was confirmed by the catalytic activity vs
glucose), strongly suggesting that FADs inside GOx are directly wired
to the GC electrode, presumably, via almost direct contact of nanotubes
with both FADs residing inside each GOx biomolecule (as basically
suggested by Guiseppi-Elie, A.; et al. Nanotechnology 2002, 13, 559–564, and shortly supported by
a number of valued researchers). Furthermore, the nonadiabatic, quasi-simultaneous
two-proton-coupled two-electron transfer/exchange mechanism was concluded
from further cross-analysis based on a generalized Marcus theory for
the proton-coupled electron transfer (PCET), extra furnished by the
first-time temperature-dependent CV studies and a subsequent Arrhenius
treatment.