Electron-transfer studies with a new flavin adenine dinucleotide dependent glucose dehydrogenase and osmium polymers of different redox potentials

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Muhammad Nadeem Zafar, Xiaoju Wang, Christoph Sygmund, Roland Ludwig, Dónal Leech, Lo Gorton
Publisher: American Chemistry Society
Publication year: 2012
Journal: Analytical Chemistry
Volume number: 84
Issue number: 1
Start page: 334
End page: 341
eISSN: 1520-6882


Abstract

A new extracellular flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase from Glomerella cingulata (GcGDH) was electrochemically studied as a recognition element in glucose biosensors. The redox enzyme was recombinantly produced in Pichia pastoris and homogeneously purified, and its glucose-oxidizing properties on spectrographic graphite electrodes were investigated. Six different Os polymers, the redox potentials of which ranged in a broad potential window between +15 and +489 mV versus the normal hydrogen electrode (NHE), were used to immobilize and “wire” GcGDH to the spectrographic graphite electrode’s surface. The GcGDH/Os polymer modified electrodes were evaluated by chronoamperometry using flow injection analysis. The current response was investigated using a stepwisely increased applied potential. It was observed that the ratio of GcGDH/Os polymer and the overall loading of the enzyme electrode significantly affect the performance of the enzyme electrode for glucose oxidation. The best-suited Os polymer [Os(4,4′-dimethyl-2,2′-bipyridine)2(PVI)Cl]+ had a potential of +309 mV versus NHE, and the optimum GcGDH/Os polymer ratio was 1:2 yielding a maximum current density of 493 μA·cm–2 at a 30 mM glucose concentration.

Last updated on 2019-12-12 at 03:44