Kinetic and thermodynamic studies of glucose oxidase catalysed oxidation reaction of glucose
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Date
2007-12-14
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World Bank Assisted Nationally Coordinated Research Programmes (NCRP), National Agricultural Research Programme (NARP)-University of Port Harcourt
Abstract
The kinetics of oxidation of D-glucose catalysed by the enzyme glucose oxidase has been studied over a wide range of experimental conditions. The reaction velocities increased with increase in the concentrations of the glucose oxidase and glucose, as well as increase in temperature and ionic strength of the solution. The reaction
velocity initially increased with increase in pH, reaching a maximum at pH 6.5 and then decreased with further
increase in pH. The reaction exhibited saturation kinetics and experimental data were analysed using the Michaelis-Menten equation. Arrhenius activation energy and thermodynamic activation parameters were measured and are reported. The large negative value of entropy of activation, ΔS≠, -148.8 JK-1mol-1, and positive value of the enthalpy of activation, ΔH≠, 26.3 kJmol-1, give further support to the proposed mechanism. The results are interpreted in terms of a mechanism involving both an oxidative half reaction and a reductive half reaction.
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Keywords
Glucose oxidase, oxidation, glucose, kinetics