Kinetic and morphological characterization of Glucose Oxidase thin layers

Immobilization of enzymes on solid surfaces has become a fundamental technique for the preparation of enzyme-based biosensors. One of the most used oxide-reductase in this field is the Glucose Oxidase enzyme (GOD). Thin layers of Glucose Oxidase have been covalently and non-covalently bound to functionalized glass cover slips. A new method for the determination of the number of immobilized GOD molecules, based on the amperometric determination of Flavin Adenine Dinucleotide (FAD), was developed. Kinetic parameters (Km, kc, and kc/Km) were measured for the immobilized GOD and compared with the unbound enzyme. Atomic Force Microscopy (AFM) images were obtain in aqueous solution for the covalently and non-covalently bound enzyme, and revealed a homogeneous coverage of the glass support by the covalently bound GOD