Modeling the kinetics of immobilized glucose oxidase

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Abstract
Determination of glucose concentrations in fluids frequently requires the application of immobilized glucose oxidase. An accurate description of the immobilized enzyme kinetics is critical for such applications. In this study, the overall rate of reaction of immobilized glucose oxidase is investigated theoretically. A novel steady-state model based on a ping-pong kinetic mechanism for glucose oxidase is developed. Numerical studies are used to examine the parameter sensitivity of this model. The enzyme loading, matrix thickness and geometric con figuration are found to have a significant influence on substrate uptake by insolubilized glucose oxidase. Aditionally, this new model is compared with a previously developed model based on an alternative ping-pong kinetic mechanism. Under steady-state conditions, no significant difference between the two models is apparent when appropriate kinetic parameters are applied to each of the models. The model developed herein is also compared with models utilizing the simplifying assumption of Michaelis–Mented kinetics for substrate reaction. Numerical studies indicate that under most realizable biological conditions, a model based on ping-pong kinetics should be applied to accurately describe substrate uptake by immobilized glucose oxidase.