Differential pulse voltammetric study of direct electron transfer in glucose oxidase chemically modified graphite electrodes

Abstract

The direct electron transfer between covalently immobilized glucose oxidase (EC 1.1.3.4) and a cyanuric chloride modified graphite electrode Is observed by use of differential pulse voltammetry. A well-defined peak at -0.51 V vs. Ag/AgCI, due to the reduction of flavin adenine dinucleotide (FAD), Is obtained which Is 100 mV more positive than the free enzyme. Comparisons to adsorbed FAD and glucose oxidase Indicate that the peak In covalently attached enzyme Is due to the reduction of the prosthetic group as part of the enzyme molecule, rather than FAD adsorbed on the electrode surface. Suggestions for the analytical utility of direct electron transfer at modified electrodes are discussed.

Preparation of the glucose sensor based on three-dimensional ordered macroporous gold film and room temperature ionic liquid

“…In GOD, FAD is deeply seated in a cavity and therefore not easily accessible for electron exchange between FAD and the electrode surface. According to the conclusion of Ianniello et al, the electrochemical response of GOD immobilized on the heterogeneous surface is due to the redox of FAD [30] . We have studied the influence of scan rate on the direct electrochemistry of GOD.…”

Preserved enzymatic activity of glucose oxidase immobilized on unmodified electrodes for glucose detection

“…The redox reaction of the native GOx is due to that of the FAD/FADH 2 redox couple (Ianniello et al, 1982), which involves the transfer of two protons and two electrons (Savitri and Mitra, 1998;Scheller et al, 1979). The formal potential of the FAD/FADH 2 redox couple at pH 7.0 is −0.43 V versus Ag/AgCl (Tinoco et al, 1978).…”

Glucose oxidase/colloidal gold nanoparticles immobilized in Nafion film on glassy carbon electrode: Direct electron transfer and electrocatalysis

“…The direct electron transfer of GOD, immobilized onto aligned nanotube electrode arrays formed by selfassembly, was studied by Liu et al [13]. Ianniello et al [14], using differential pulse voltammetry, studied the direct electron transfer of adsorbed GOD at a graphite electrode and a cyanuric Bioelectrochemistry 69 (2006) 158 -163 www.elsevier.com/locate/bioelechem chloride-modified graphite electrode. So developing novel and convenient method to fulfill the direct electron transfer of GOD has great significance.…”