ELECTRON-TRANSFER ON AN ELECTRODE OF GLUCOSE-OXIDASE IMMOBILIZED IN POLYANILINE

An electrode composed of glucose oxidase (GOD) immobilized in electrop olymerized polyaniline (PANI) on a Pt wire of diameter 0.5 mm was prep ared. Scanning tunneling micrographs of both PANI and GOD + PANI showe d a wavy long-chain polymer structure, but the latter appeared smoothe r, thicker and well distributed. The dependences of the oxygen reducti on current and the glucose-reduced GOD oxidation current on the glucos e concentrations were found from cyclic voltammograms of a GOD + PANI + Pt electrode in glucose solutions. The compound 7-acetyl-10-methyl i soalloxazine (C13H10N4O3) was used as a model of the redox center on t he GOD molecule. The results showed that at a potential of -0.3 V/SCE glucose-reduced GOD could be oxidized again and direct electron transf er could occur from the active redox center of the enzyme to the Pt su rface through an electron pathway in GOD + PANI and its model electrod es.