CHARACTERIZATION OF THE BIOCHEMICAL BEHAVIOR OF GLUCOSE-OXIDASE ENTRAPPED IN A POLYPYRROLE FILM

This article reports the characterization of the biochemical behavior of glucose oxidase entrapped in polypyrrole. The immobilization of glucose oxidase in a polypyrrole film was performed by entrapment during the electropolymerization of pyrrole at a platinum electrode poised at 0.65 V vs. SCE in aqueous solution in a one-compartment electrochemical cell. Thin films of polypyrrole (0.11-mu-m) were obtained and the entrapped enzyme obeyed Michaelis kinetics, indicating no diffusional constraints of the substrate. Our results indicate that the entrapped glucose oxidase is more resistant to denaturation conditions such as alkaline pH and temperature (50 and 60-degrees-C) than the soluble form of the enzyme. The autoinactivation constant for the entrapped enzyme was also determined in presence of 0.25M of glucose and was 6.19 x 10(-4) min-1, i.e., corresponding to a half-life value of 20 h. The results reported here show clearly that polypyrrole matrix has a strong stabilizing effect on the structure and on the activity of glucose oxidase.