Bioelectrocatalytic oxidation of glucose by hexose oxidase directly wired to graphite

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Glucose-oxidizing enzymes are widely used in electrochemical biosensors and biofuel cells; in most applications glucose oxidase, an enzyme with non-covalently bound FAD and low capability of direct electronic communications with electrodes, is used. Here, we show that another glucose-oxidizing enzyme with a covalently bound FAD center, hexose oxidase (HOX), adsorbed on graphite, exhibits a pronounced non-catalytic voltammetric response from its FAD, at -307 mV vs. Ag/AgCl, pH 7, characterized by the heterogeneous electron transfer (ET) rate constant of 29.2 +/- 4.5 s(-1). Direct bioelectrocatalytic oxidation of glucose by HOX proceeded, although, with a 350 mV overpotential relative to FAD signals, which may be connected with a limiting step in biocatalysis under conditions of the replacement of the natural redox partner, O-2, by the electrode; mediated bioelectrocatalysis was consistent with the potentials of a soluble redox mediator used. The results allow development of HOX-based electrochemical biosensors for sugar monitoring and biofuel cells exploiting direct ET of HOX, and, not the least, fundamental studies of ET non-complicated by the loss of FAD from the protein matrix. (C) 2016 Elsevier B.V. All rights reserved.

Original languageEnglish
JournalElectrochemistry Communications
Volume65
Pages (from-to)1-4
Number of pages4
ISSN1388-2481
DOIs
Publication statusPublished - Apr 2016

    Research areas

  • Hexose oxidase (HOX), Bioelectrocatalysis, Direct electron transfer, Glucose oxidation, DIRECT ELECTRON-TRANSFER, FLAVIN ADENINE-DINUCLEOTIDE, HORSERADISH-PEROXIDASE, ENZYME ELECTRODES, GOLD ELECTRODE, NADH OXIDATION, GLASSY-CARBON, FUEL-CELLS, ELECTROCATALYSIS, FLAVOHEMOGLOBIN

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