Fast electron transfer between glucose oxidase and electrodes via phenothiazine mediators with poly (ethylene oxide) spacers attached to the enzyme surface

A series of glucose oxidase hybrids capable of a direct electrical communication with electrodes is synthesized by covalently bonding phenothiazine mediators to surface lysine residues via poly(ethylene oxide) spacers with different lengths. The hybrid with the optimum length of spacer chain exhibits the fast electron transfer between the redox center of enzyme and electrodes. This fast electron transfer in the hybrids realizes a large catalytic current comparable to that for the corresponding freely diffusing mediator systems.