Kinetics of glucose oxidase catalyzed electron transfer mediated by sulfur and selenium compounds.
Unusually high electron transfer rates in Aspergillus niger glucose oxidase catalyzed oxidation of glucose using 5,6:11,12-Bis(dithio)tetracene (TTT), 1,2-dimethyltetraselenafulvalene (DMTSF) and tetrathiafulvalene (TTF) were observed. At pH 7.0 oxidation rate constants (TN/Km) in the range from 1.0.10(7) to 8.7.10(7) M.s-1 were deduced from experimental data. One of the investigated mediators, DMTSF, has been used for electrocatalytical glucose oxidation on graphite at a potential of 0.3 V vs. a standard calomel electrode (SCE). The prepared bioelectrodes have a sensitivity of 1.3 microA/(cm2.mM), a pH optimum at 6.5-7.0, and a linear range which covers the relevant range for monitoring physiological levels of glucose. The bioelectrodes are stable for more than one month.
Kulys
J
J
Institute of Biochemistry, Vilnius, Lithuania.
Buch-Rasmussen
T
T
Bechgaard
K
K
Marcinkeviciene
J
J
Christensen
J B
JB
Hansen
H E
HE
D001234:Aspergillus niger / Q000201:enzymology; D002384:Catalysis; D004220:Disulfides / Q000378:metabolism; D004563:Electrochemistry; D004566:Electrodes; D004579:Electron Transport; D005947:Glucose / Q000378:metabolism; D005949:Glucose Oxidase / Q000378:metabolism*; D006108:Graphite; D006571:Heterocyclic Compounds / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009279:Naphthacenes / Q000378:metabolism; D016566:Organoselenium Compounds / Q000378:metabolism; D010084:Oxidation-Reduction; D012643:Selenium / Q000378:metabolism*; D013053:Spectrophotometry; D013455:Sulfur / Q000378:metabolism*
C082724:1,2-dimethyltetraselenafulvalene; C082725:5,6-11,12-bis(dithio)tetracene; D004220:Disulfides; D006571:Heterocyclic Compounds; D009279:Naphthacenes; D016566:Organoselenium Compounds; D013455:Sulfur; D006108:Graphite; D005949:Glucose Oxidase; D012643:Selenium; C063887:tetrathiafulvalene; D005947:Glucose