Indirect evidence of direct electron communication between the active site of galactose oxidase and a graphite electrode.
Bi-enzymatic biosensor based on galactose oxidase (GalOD) and horseradish peroxidase (HRP) using ferrocene as an efficient mediator was constructed. When a dependence of a working potential on the sensor performance was examined, an unusual behaviour was observed. With increasing of an applied working potential a lower concentration of substrate to attain full linear range was needed. A fully linear dependence from the first substrate addition was observed at and above the working potential of 150 mV. This activation of the biosensor response by an applied working potential very well corresponds with a formal potential of GalOD (156 mV). When a membrane prevented GalOD access to the electrode surface was applied, no activation effect of a working potential on the sensor performance was observed. Thus, it can be assumed that direct electron communication between GalOD and the electrode occurred.
Tkac
Jan
J
Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, SK-842 38, Bratislava, Slovak Republic. chemtkac@savba.sk
Vostiar
Igor
I
Gemeiner
Peter
P
Sturdik
Ernest
E
D001665:Binding Sites; D015374:Biosensing Techniques; D004566:Electrodes; D004583:Electrons; D005692:Galactose Oxidase / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry
D006108:Graphite; D005692:Galactose Oxidase; D006735:Horseradish Peroxidase