Rotating disc electrode characterization of immobilized glucose oxidase.
The kinetic properties of glucose oxidase (EC 1.1.3.4) which has been covalently immobilized to a rotating glassy carbon electrode surface have been investigated. Analysis of the rotation rate dependence of the hydrogen peroxide-derived current suggests that oxygen mass transport to the enzyme-electrode surface is rate controlling at low rotation rates. Only as the diffusion layer approaches zero thickness (i.e., infinitely fast rotation rate) does mass transport become unimportant. A diffusion-free glucose Km for air-saturated buffer is found to be 66 mM using this methodology. The importance of mass transport restrictions in two-substrate enzymes such as glucose oxidase is discussed in the context of biosensor design.
Mikkelsen
S R
SR
Department of Chemistry, McGill University, Montreal, Quebec, Canada.
Lennox
R B
RB
D004563:Electrochemistry; D004800:Enzymes, Immobilized; D005949:Glucose Oxidase / Q000502:physiology*; D007700:Kinetics; D012399:Rotation
D004800:Enzymes, Immobilized; D005949:Glucose Oxidase