title: A homogeneous enzyme immunoassay with avidin-ligand conjugate as the enzyme-modulator.
abstract: A homogeneous enzyme immunoassay (EIA) based on the immunomodulation of an avidin-ligand conjugate and the inhibition of pyruvate carboxylase is described. The conjugation of the ligand, 5,5-diphenylhydantoin (DPH), to avidin does not affect avidin's capacity to bind biotin or inhibit pyruvate carboxylase. The DPH-avidin conjugate and free DPH were shown to compete for a limited number of antibody sites. The interaction of anti-DPH with the DPH-avidin conjugate sterically inhibited enzyme inactivation. Enzyme activity was correlated with DPH concentrations in the therapeutic range found in serum.
mesh_terms: D001360:Avidin; D001666:Binding Sites, Antibody; D001710:Biotin; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D007124:Immunoenzyme Techniques; D010672:Phenytoin; D011766:Pyruvate Carboxylase / Q000037:antagonists & inhibitors; D011863:Radioimmunoassay
chemical_list: D001360:Avidin; D010672:Phenytoin; D001710:Biotin; D011766:Pyruvate Carboxylase