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Improvement of a sensitive enzyme‐linked immunosorbent assay for screening estrogen receptor binding activity
Author(s) -
Koda Tomoko,
Soya Yoshihiro,
Negishi Harumi,
Shiraishi Fujio,
Morita MAsatoshi
Publication year - 2002
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620211203
Subject(s) - chemistry , estrogen receptor , diethylstilbestrol , competitive binding , nonylphenol , enzyme , immunoassay , chromatography , bisphenol a , non competitive inhibition , ic50 , receptor , estrogen , iodide , ligand binding assay , biochemistry , in vitro , medicine , endocrinology , environmental chemistry , biology , antibody , hormone , organic chemistry , immunology , cancer , breast cancer , epoxy
A competitive enzyme‐linked immunosorbent assay (ELISA) with estrogen receptor (a) and a fluorescence depolarization method with Full‐Range Beacon were examined as estrogen receptor binding assays to prescreen endocrine‐disrupting chemicals (EDCs). In this study, because it is difficult to measure the receptor binding ability of sparingly water‐soluble chemicals using these methods, the competitive enzyme immunoassay was further modified for improved sensitivity by changing the operational parameters, such as receptor concentration, ligand concentration, and the reaction temperature. The method was applied to 10 test chemicals, including alkylphenols and bisphenol A (BPA). The diethylstilbestrol (DES) relative binding affinity (RBA) of ELISA kit was set equal to 1 (RBA = IC50/IC50 of DES). The RBAs of BPA, 4‐nonylphenol ( p ‐NP), and 4‐ t ‐octylphenol (p‐ t ‐OP) are 5386, 8619, and 8121 before using the improved competitive enzyme immunoassay and 883, 699, and 2832 using improved it respectively. Mixtures of BPA, p‐NP, and p‐t‐OP gave results that the estrogen binding affinities of these chemicals are additive or slightly more than additive.