Antigen-Antibody Immobilization of Glucose Oxidase. Kinetic Analysis

Antigen-Antibody Immobilization of Glucose Oxidase. Kinetic Analysis 

Determining the thermodynamics and kinetics of recognition between biomolecules, particularly when one of the two is immobilized on a substrate, is of considerable current interest, as for example, antibody-antigen recognition, recognition of single-stranded DNA oligonucleotides by partially or totally complementary DNA strands, and many other possible analytical applications. 

Determination of the thermodynamic and kinetic parameters of interest requires monitoring of the surface concentration of the binding molecule. With large biomolecules, the surface concentrations are small, and simple redox labeling will not allow sufficient sensitivity. Labeling of the target biomolecule with a redox enzyme obviates this difficulty, thanks to the catalytic properties of the enzyme. 

Zones I and R corresponds to an irreversible and a reversible binding, respectively. A and D represent the kinetic controls by the binding reaction 

The dissociation of the complex upon exposure to a pure solution after it has reached its equilibrium value may be examined similarly. At time t = 0, 0 = 0 = k/( I k) = KC Z(1 + KC ), where Cg is the bulk concentration that was used during the adsorption step preceding the desorption process. Assuming that the volume-to-surface ratio is large enough for the bulk concentration of B to remain negligible throughout the experiment, the variation in the surface concentration with time obeys the equation 

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