Direct electron transfer of fructose dehydrogenase immobilized on thiol-gold electrodes

Direct electrochemical electron transfer (DET) of oxidoreductases has attracted increasing attention in pure and applied bioelectrochemistry (e.g. biosensors biofuel cells) over the last decades. We report here a systematic study DET-type bioelectrocatalysis membrane-bound redox enzyme fructose dehydrogenase (FDH, Gluconobacter sp.), on variable-length variably terminated thiol self-assembled monolayers (SAMs) both Au(111) nanoporous gold (NPG) electrodes. FDH modified by short-chain moderately hydrophilic 2-mercaptoethanol (BME) SAMs exhibits highest DET activities largest DET-capable fraction. Fitting theoretical polarization curves to data homology modeling/docking offer further mechanistic insight. The dependence efficiency length differently carbon chain is systematically presented. decreased rate with associated increasingly unfavourable long-range tunnelling, not lowered loading. porous structure NPG favorable for improving efficient orientation operational stability. Overall, our maps controlled local environmental structural flexibility Au/SAM/enzyme/solution interface, paradigm surfaces bioelectronics.