Kinetics and equilibrium in the immunoradiometric assay (IRMA) of thyroglobuline

Biexponential model for the kinetics of the substitution reaction in the radioimmunoassay of triiodothyronine

The influence of initial concentrations, ionic strength, viscosity and temperature on the substitution reaction of 125I-triiodothyronine (T3) (M) by unlabelled T3 (Q) in the immunocomplex PM (P = anti-T3 antibody) has been studied, and a kinetic model is proposed. The apparent rate constant is dependent on the initial concentration of labelled and unlabelled T3, viscosity and temperature, and independent of ionic strength. The reaction is endothermic and is not controlled by diffusion. The results obtained are in line with the proposed model. We propose some modifications for optimizing the technique.

Kinetics of Androstendione‐Radioactive Immunocomplex Substitution Reaction

A kinetic model is put forward for the study of the antigen-antibody reactions involved in the coated tube radioimmunoassay (RIA) of androstendione. Twenty experiments were conducted to determine the influence of initial concentrations, ionic strength, viscosity, and temperature on the substitution reaction of 125I-androstendione (M) by unlabelled androstendione (Q) in the immunocomplex PM (P = anti-androstendione antibody). The results obtained are in line with the proposed model. The concentration of radioactive immunocomplex is directly proportional to the initial concentration of labelled androstendione and independent of the concentration of unlabelled androstendione, ionic strength, and viscosity. The reaction is not diffusion-controlled.

Comparison between mono- and bi-exponential models for reaction kinetics in the immunoradiometric assay of neuron-specific enolase

This paper studies the kinetics of the antigen-antibody reactions involved in the analytical determination of neuron-specific enolase (NSE) by means of radiometric immunoassay (IRMA). For the global process, kinetics were found to be dependent on analyte and labelled antibody concentrations, such dependence fitting with the models described in previous papers. Viscosity results clearly indicate its negative influence on the direct reaction rate. Ionic strength shows noticeable but not too relevant effects, which suggests that the variation caused by the glycerol addition is not due to the influence of the dielectric constant of the solutions used. The effect of temperature shows activation parameters similar to the viscous flow energy of water, which suggests diffusion control for the global process. The analysis of the kinetic data of the experiences conducted can be explained by admitting that the antigen-antibody binding takes place through two different binding site types.