High throughput screening fluorescence polarization assays using G protein-coupled receptors (GPCRs) as targets have been compared using fluorescein and BODIPY TMR-labeled peptides. The red-shifted BODIPY TMR dye exhibits improved assay performance relative to fluorescein due to improvement in both ligand affinity to the GPCRs and assay precision brought about by the higher intensity probe. Furthermore, the red-shifted dye demonstrates an insensitivity to the effects of the highly colored compound tartrazine, which can produce false-negative results for assays conducted with fluorescein as a label.
