Implications of FAD Electrode Reaction Kinetics for Electrocatalysis of NADH Oxidation and Development of NAD-Dependent Enzyme Electrodes

摘要

FAD entrapped into the polyethyleneimine (PEI) matrix underwent 2e~-/2H~+ redox transformation, in contrast to the 1e~-/1H~+ reaction observed with nonstabilized FAD-modified electrodes. Under conditions of the 2e~-/2H~+ reaction, FAD/PEI-modified electrodes catalytically oxidized NADH starting from -100 mV vs. Ag/AgCl. These electrodes may be used for construction of NAD-dependent dehydrogenase electrodes for clinically important analytes such as glucose when coupled to the model enzyme glucose dehydrogenase. Latter allows detection of glucose starting from -100 mV within 0.05–5 mM concentration range. These results suggest the FAD stabilization by different matrices as a simple and promising approach to achieve its 2e~-/2H~+ redox chemistry resulting in catalysis of NADH oxidation.