ELECTRON-TRANSFER BETWEEN GLUCOSE-OXIDASE AND ELECTRODES VIA REDOX MEDIATORS BOUND WITH FLEXIBLE CHAINS TO THE ENZYME SURFACE

Electrical communication between redox centers of glucose oxidase and vitreous carbon electrodes is established through binding to oligosaccharides, at the periphery of the enzyme, ferrocene functions pendant on flexible chains. Communication is effective when the chains are long ( > 10 bonds), but not when the chains are short ( < 5 bonds). When attached to long flexible chains, the peripherally bound relays penetrate the enzyme to a sufficient depth to reduce the electron-transfer distances between a redox center of the enzyme and the relay and between the relay and the electrode, thereby increasing the rate of electron transfer.