| Abstract
| - The characteristics of a novel cathode on which O2 is electroreduced to water under physiological conditions(pH 7.4, 0.15 M NaCl, 37.5 °C) are reported. The cathode was made by electrically connecting (“wiring”)redox centers of bilirubin oxidase (BOD) from Trachyderma tsunodae (Tt) to carbon electrodes through aredox polymer. The cathode was more stable than that made by wiring BOD from Myrothecium verrucaria(Mv) (N. Mano et al., J. Am. Chem. Soc. 2002, 124, 6480−6486) (5% loss of current per day of operation vs10%), and its operating potential at 3 mA cm-2 current density was −140 mV vs the potential of the reversibleO2/H2O electrode, 50 mV higher than that of the Mv-BOD cathode. The improved stability is attributed tostronger electrostatic bonding in the adduct of Tt-BOD with the “wiring” redox polymer, and the higheroperating potential to the replacement of methionine by phenylalanine in the axial position of the type 1Cu+/2+ center, which upshifts the center's potential.
|
