Electron transfer studies with different sugar oxidizing enzymes and osmium polymers to improve the current density

Muhammad N. Zafar 1Xiaoju Wanga 2Roland Ludwig 3Donal Leech 4Lo Gorton 1

1. Lund University, Department of Analytical Chemistry and Biochemistry, Lund 22100, Sweden
2. Abo Akademi University, Process Chemistry Centre, Laboratory of Analytical Chemistry, Biskopsgatan 8, Turku FIN-20500, Finland
3. University of Natural Resources and Applied Life Sci Department of Food Sciences and Technology, Vienna A-1190, Austria
4. National University of Ireland, Galway (NUIG), University Road, Galway none, Ireland

Glucose dehydrogenase (GDH) from Glomerella cingulata(GcGDH, EC is an extracellular redox enzyme. The native enzyme is a monomeric glycosylated polypeptide and has one non-covalently bound flavin adenine dinucleotide (FAD) molecule acting as the redox cofactor. Pyranose dehydrogenase from Agaricus meleagris (AmPDH, EC is an extracellular redox enzyme. The native enzyme is a monomeric glycosylated polypeptide and has a molecular mass of 66,547 Da, containing 7% carbohydrates and one covalently bound flavin adenine dinucleotide (FAD) molecule acting as the redox cofactor. PDH can oxidise its substrate at the C-1, C-2 or C-3 as well as perform double oxidation at C-1,2, C-2,3 and it has no anomeric specificity [1].

This new extracellular redox enzyme, flavin adenine dinucleotide (FAD) dependent glucose dehydrogenase from Glomerella cingulata(GcGDH) was electrochemically studied to catalyze the oxidation of glucose on spectrographic graphite electrode. Six Os polymers, whose redox potentials are ranged in a broad potential window between +15 and +489 mV vs. NHE, were used to “wire” the GcGDH on spectrographic graphite electrodes for possible applications in biosensors and biofuel cells. [2, 3]. The GcGDH/Os-polymer modified electrodes were evaluated in a chronoamperometric mode using FIA.  The current response was investigated under a step-wisely increased potential window. The performance of the redox polymers for enzyme wiring was investigated using glucose as substrate. The current response was investigated under a step-wisely increased potential window. The ratio between GDH:Os-polymer was optimized. It was observed that the ratio between GDH:Os-polymer in the overall loading of the enzyme electrode significantly affects the performance of the enzyme electrode on catalyzing the glucose oxidation. The best Os-polymer had a potential of +309 mV vs. NHE and GcGDH:Os-polymer ratio was 1:2 yielding a maximum current density of 493 µAcm-2 for 30 mM glucose was produced by the GcGDH/Os c modified electrode.

After characterization of GcGDH, we coimmobilized equal units of GcGDH with AmPDH enzymes along with Os-polymer c on graphite electrodes to improve the current density. With this coimmobilization of both enzymes, we were successfully able to improve the current density. The reason for this improvement is that AmPDH enzyme also can oxidize the products of GcGDH enzyme due to its ability to oxidize at C-1, C-2 or C-3 as well as doubleoxidation at C-1,2, C-2,3.


[1] C.K. Peterbauer, J. Volc, Pyranose dehydrogenases: biochemical features and perspectives of technological applications, Appl. Microbiol. Biotechnol., 85 (2010) 837–848.

[2] Muhammad Nadeem Zafar, Federico Tasca, Susan Boland, Magdalena Kujawa, Ilabahen Patel, Clemens K. Peterbauer, Donal Leech, Lo Gorton, “Wiring of pyranose dehydrogenase with osmium polymers of different redox potentials”, Bioelectrochemistry, 80: 38-42 November 2010.

[3] F. Mao, N. Mano, A. Heller, Long tethers binding redox centers to polymer backbones enhance electron transport in enzyme “wiring” hydrogels, J. Am. Chem. Soc. 125 (2003) 4951–4957.


Related papers
  1. Effect of deglycosylation of cellobiose dehydrogenase applied to 3rd generation biosensors and biofuel cells
  2. Deglycosylation of glucose oxidase by PNGase F
  3. Influence of metal cations on the turnover rate of cellobiose dehydrogenase
  4. Gold nanoparticle-modified enzyme-based sugar and oxygen sensitive electrodes for biosensing and biofuel cell applications
  5. Electrochemical communication between viable bacterial cells and flexible redox polymers
  6. Enzyme-amplified amperometric DNA hybridization assay based on bioelectrocatalysis using redox-polymer modified electrodes
  7. Direct electrochemistry of cellobiose dehydrogenase for applications in the third-generation biosensor and biofuel cell
  8. Electrochemical Communication between Viable Bacterial Cells and Flexible Redox Polymers
  9. Biosensing Applications Of Engineered Pyranose 2-oxidases Wired With Osmium Polymers
  10. Modification of gold microelectrodes for detection of DNA hybridization
  11. Mediated enzyme reactions: coupling biological electron transfer to electrodes with redox complexes
  12. Modification of electrode surfaces with redox complexes for biosensor and biofuel cell applications
  13. Anode and cathode reactions for biofuel cells based on direct electron transfer reactions between biological components and electrodes
  14. Increasing Biosensor Sensitivity by Length Fractionated Single Walled Carbon Nanotubes
  15. Electrical Wiring of Living Bacillus subtilis Cells Using Flexible Osmium-Redox Polymers
  16. Some electrochemical properties of laccase immobilised on the Au, IrOx, or C60-Pd polymer electrode supports
  17. Oxygen electroreduction by fungal laccases - combination of electrochemical and spectral data
  18. Wiring of whole living bacteria with osmium-redox polymers
  19. The electrochemistry of a his-tagged microperoxidase assembled onto gold electrodes
  20. Electron Transfer in Complex Two-cofactor-containing Enzymes at Alkanethiol-modified Gold Electrodes

Presentation: Poster at SMCBS'2011 International Workshop, by Muhammad N. Zafar
See On-line Journal of SMCBS'2011 International Workshop

Submitted: 2011-08-29 12:51
Revised:   2011-09-22 14:58