ELECTROANALYTICAL X-RAY PHOTOELECTRON-SPECTROSCOPY INVESTIGATION ON GLUCOSE-OXIDASE ADSORBED ON PLATINUM

Glucose oxidase has been adsorbed on Pt from a solution of the enzyme (0.5-15 mumol dm-3) in phosphate or acetate buffer (pH 3.9-8.0). The amperometric response to glucose of the modified electrodes so prepared has been evaluated. A spectroscopic (XPS) investigation of the system surface indicates that the enzyme molecules are stacked on the Pt surface, some directly interacting with the metal and the remaining part adsorbed on them. At the surface, the enzyme has a conformation in which its carbohydrate part tends to cover the proteic portion.