Step-by-step avidin-biotin construction of bienzyme electrodes. Kinetic analysis of the coupling between the catalytic activities of immobilized monomolecular layers of glucose oxidase and hexokinase
N. Anicet et al., Step-by-step avidin-biotin construction of bienzyme electrodes. Kinetic analysis of the coupling between the catalytic activities of immobilized monomolecular layers of glucose oxidase and hexokinase, LANGMUIR, 15(19), 1999, pp. 6527-6533
Avidin-biotin technology is used to achieve the step-by-step construction o
f electrode coatings in which two monomolecular layers of biotinylated hexo
kinase are immobilized on top of five monomolecular layers of biotinylated
glucose oxidase. The two enzymes compete for the consumption of glucose. Be
cause the reaction of hexokinase with glucose depends on the presence and c
oncentration of ATP in the solution, the electrochemical response is sensit
ive to the ATP concentration. Such a system illustrates the possibility of
translating the catalytic activity of a nonredox enzyme into an electrical
signal within a spatially ordered structure. Full kinetic analysis of the e
lectrochemical responses allowed a description of the diffusion controlled
communication between the two enzymes over distances that are comparable to
those involved in enzyme coupling in cell cytoplasmic systems.