This kit contains Goat Tb-Anti-GST antibody; other kit components are the same as kit A15122: The LanthaScreen® TR-FRET Retinoic Acid Receptor (RAR) alpha Coactivator Assay Kit provides a sensitive and robust method for high-throughput screening of potential RAR alpha ligands as agonists of coactivator recruitment. The homogeneous mix-and-read assay format results in a ligand EC50 composite value representing the amount of ligand required to bind to receptor, effect a conformational change, and recruit coactivator peptide (Figure 1). How it works The LanthaScreen® TR-FRET RAR alpha Coactivator Assay Kit includes a terbium (Tb)-labeled anti-GST antibody, a fluorescein-labeled coactivator peptide, and a human RAR alpha ligand-binding domain (RAR alpha-LBD) that is tagged with glutathione-S-transferase (GST). To assay, RAR alpha-LBD is added to ligand test compounds, followed by addition of a mixture of the fluorescein-coactivator peptide and Tb-anti-GST antibody. After room temperature incubation, the TR-FRET 520:495 emission ratio is calculated and used to determine the EC50 from a dose response curve of the compound. Contents and Storage: The LanthaScreen® TR-FRET RAR alpha Coactivator Assay Kit contains RAR alpha-LBD (GST) protein, fluorescein-labeled D22 coactivator peptide, Tb-anti-GST antibody, and buffers. Store components as indicated in the assay protocol (-80°C, -20°C, or +4°C).