The PolarScreen™ ER Alpha Competitor Assay, Red kit assesses the affinity of test compounds to ERα (66 kDa). ERα is added to a fluorescent estrogen ligand to form an ER/Fluormone™EL Red complex. This complex is then added to individual test compounds in multiwall plates. To determine relative affinity, the assay measures fluorescence polarization. Competing test compounds will displace the Fluormone™EL Red ligand from ERα permitting it to tumble rapidly and result in low polarization value. By using longer wavelength excitation (530 nm) than used for the ER Competitor Assay, Green kits the problem of intrinsic fluorescence found in some test compounds is greatly reduced.

Note: Using the conditions recommended in the Certificate of Analysis, this kit will perform 2,500 × 20µl assays. Other protocols may require larger volumes of reagent per assay.