Abstract: By electrochemical polymerization of pyrrole in phosphate buffer, glucose oxidase (GOD) was entrapped in polypyrrole matrix (PPy) to construct the enzyme electrode. Effects of electropolymerization conditions, such as pH values and electrode potentials, on the enzyme immobilization were studied. Behavior of GOD/PPy membranes was characterized by IR and a.c. impedance spectra. The immobilization of GOD will be accomplished only if pH>5.5. It is likely that GOD enters into PPy in its entity with negative charge. Spectra of a.c. impedance show that the enzyme electrode has the features similar to porous electrodes. It was edmonstrated that the simultaneous immobilization of GOD and mediator Fe(CN)_6~(3-) is feasible. The electrcchemically immobilized GOD maintains its biocatalytic activeties, and apparently the enzymatic reaction follows Michaelis-Menten kinetics.

Key words: Enzyme electrode, Enzyme immobilization, Electropolymerization, Polypyrrole, Glucose oxidase