title: Homogeneous enzyme immunoassay of estriol in picogram amounts.
abstract: A homogeneous enzyme immunoassay for estriol has been described using estriol-glucose-6-phosphate dehydrogenase (E3G6PD) as enzyme conjugate. Antisera for estriol were raised by immunising rabbits with two different immunogens, estriol-6-(O-carboxymethyl oxime) bovine serum albumin (E36CMOBSA) and estriol-3-carboxymethyl ether bovine serum albumin (E33CMEBSA). A new method for preparation of estriol 3-O-carboxymethyl ether in high yield (90%) has also been described. Addition of anti-estriol antibodies to E3-G6PD conjugate resulted in inhibition of enzyme activity. In the presence of free estriol, the antibody induced inhibition of enzyme activity was reduced in a concentration dependent manner. The use of the heterologous combination between immunogen and enzyme conjugate, i.e. using anti-E33CMEBSA and E36CMOG6PD improves the sensitivity at the expense of specificity, the cross-reaction with other estrogenic hormone being 10-15%.
mesh_terms: D000918:Antibody Specificity; D004964:Estriol / Q000031:analogs & derivatives / Q000032:analysis* / Q000276:immunology / Q000494:pharmacology; D005954:Glucosephosphate Dehydrogenase / Q000037:antagonists & inhibitors; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007118:Immunoassay / Q000379:methods*; D008832:Microchemistry
chemical_list: D007106:Immune Sera; C002913:estriol-6-(O-carboxymethyl)oxime; C037764:estriol-3-carboxymethyl ether; D005954:Glucosephosphate Dehydrogenase; D004964:Estriol