title: A homogeneous bioelectrochemical immunoassay for thyroxine.
abstract: Thyroxine has been modified with a ferrocene derivative to produce an immunologically reactive conjugate which remains capable of functioning as an electron transfer mediator, shuttling electrons between an oxido-reductase enzyme and an electrode. On binding with an anti-thyroxine antibody the conjugate's ability to function as a mediator is impaired. The conjugate has been used as a tracer in an homogeneous competitive assay to quantify the total thyroxine concentration in serum, the assay being measured electrochemically after the addition of a suitable oxidoreductase enzyme (glucose oxidase) and its substrate (glucose) on completion of antibody/antigen binding. This results in a simple and sensitive assay for thyroxine.
mesh_terms: D004563:Electrochemistry; D005296:Ferrous Compounds; D005949:Glucose Oxidase; D006801:Humans; D007106:Immune Sera; D007118:Immunoassay / Q000379:methods; D007202:Indicators and Reagents; D013974:Thyroxine / Q000032:analysis* / Q000097:blood
chemical_list: D005296:Ferrous Compounds; D007106:Immune Sera; D007202:Indicators and Reagents; D005949:Glucose Oxidase; D013974:Thyroxine