Spectroelectrochemical Investigation of GMC Flavoenzymes
Biological and Biomimetic Chemistry
Physical Chemistry of Solids and Surfaces, Material Characterisation
Final Report Abstract
Glucose-oxidizing enzymes are of utmost importance for example for the development of glucose biosensors (for diabetes management) or for the use in glucose biofuel cells. The exact knowledge of the redox potential of these enzymes will help to optimize sensor applications in this field. In the project “Spectroelectrochemical Investigation of GMC Flavoenzymes” the redox potentials of the enzymes Cholesterol Oxidase from Streptomyces lividans, Cellobiose Dehydrogenase from Myriococcum thermophilum (MtCDH) and Cholin Oxidase from Arthrobacter globiformis (AgCOx) at different pH values were determined spectroelectrochemically. The FAD containing enzyme SlChOx was studied by spectroelectrochemistry between pH 5 and pH 9. In the entire pH range, the occurrence of a stable flavosemiquinone radical anion (Flrad-) was observed. From the spectroelectrochemical data, the pH-dependent midpoint potentials as well as the redox potentials for the first and second transition (Flox)/Flrad-) and (Flrad-/Flred-) were determined. For the glucose-oxidizing flavoheme enzyme MtCDH the midpoint potentials were determined spectroelectrochemically in the pH range of 6 to 8, after the enzyme had been produced and purified in our own laboratory. Also the choline oxidizing enzyme AgCOx was investigated spectroelectrochemically and the redox potentials for this enzyme were determined in the pH range between 6 and 8. The planned implementation of a coulometric working mode was started. First test measurements were carried out, but unfortunately could not be finished due to a delay caused by corona restrictions and several problems that occurred during the project period. Nevertheless, three different enzymes were investigated and the redox potentials were determined at different pH values.
