Characterization of different FAD-dependent glucose dehydrogenases for possible use in glucose-based biosensors and biofuel cells.
In this study, different flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenases (FADGDHs) were characterized electrochemically after "wiring" them with an osmium redox polymer [Os(4,4'-dimethyl-2,2'-bipyridine)(2)(PVI)(10)Cl](+) on graphite electrodes. One tested FADGDH was that recently discovered in Glomerella cingulata (GcGDH), another was the recombinant form expressed in Pichia pastoris (rGcGDH), and the third was a commercially available glycosylated enzyme from Aspergillus sp. (AspGDH). The performance of the Os-polymer "wired" GDHs on graphite electrodes was tested with glucose as the substrate. Optimal operational conditions and analytical characteristics like sensitivity, linear ranges and current density of the different FADGDHs were determined. The performance of all three types of FADGDHs was studied at physiological conditions (pH 7.4). The current densities measured at a 20 mM glucose concentration were 494 ± 17, 370 ± 24, and 389 ± 19 μA cm(-2) for GcGDH, rGcGDH, and AspGDH, respectively. The sensitivities towards glucose were 2.16, 1.90, and 1.42 μA mM(-1) for GcGDH, rGcGDH, and AspGDH, respectively. Additionally, deglycosylated rGcGDH (dgrGcGDH) was investigated to see whether the reduced glycosylation would have an effect, e.g., a higher current density, which was indeed found. GcGDH/Os-polymer modified electrodes were also used and investigated for their selectivity for a number of different sugars.
Department of Biochemistry and Structural Biology, Lund University, Lund, Sweden. MNadeem.Zafar@biochemistry.lu.se
Muhammad Nadeem
MN
Zafar
Najat
N
Beden
Dónal
D
Leech
Christoph
C
Sygmund
Roland
R
Ludwig
Lo
L
Gorton
D001230:Aspergillus / Q000201:enzymology; D001674:Bioelectric Energy Sources; D015374:Biosensing Techniques / Q000379:methods*; D005182:Flavin-Adenine Dinucleotide / Q000737:chemistry / Q000378:metabolism*; D005947:Glucose / Q000032:analysis*; D005948:Glucose Dehydrogenases / Q000737:chemistry / Q000378:metabolism*; D006108:Graphite / Q000737:chemistry; D009992:Osmium / Q000737:chemistry; D010084:Oxidation-Reduction; D020081:Phyllachorales / Q000201:enzymology; D011108:Polymers / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012680:Sensitivity and Specificity
D011108:Polymers; D011994:Recombinant Proteins; D005182:Flavin-Adenine Dinucleotide; D009992:Osmium; D006108:Graphite; D005948:Glucose Dehydrogenases; D005947:Glucose