The TR-FRET PPAR alpha Competitive Binding Assay provides a sensitive and robust method for high-throughput screening (HTS) of ligands for peroxisome proliferator-activated receptor alpha (PPAR alpha). The kit uses a terbium-labeled anti-GST antibody, a fluorescent small-molecule pan-PPAR ligand (Pan-PPAR Green), and a human PPAR alpha ligand-binding domain (LBD) that is tagged with glutathione S-transferase (GST), in a homogeneous mix-and-read assay format.
To assay:
When running the TR-FRET PPAR alpha Competitive Binding Assay, Pan-PPAR Green is added to ligand test compounds followed by addition of a mixture of the PPAR alpha-LBD and terbium anti-GST antibody. When the Pan-PPAR Green is bound to PPAR alpha, energy transfer from the terbium-labeled antibody to the tracer occurs, and a high TR-FRET ratio is observed. Competitive ligand binding to PPAR alpha is detected by a test compound?s ability to displace the tracer, which results in a loss of FRET between the antibody and the tracer. After an incubation period at room temperature, the 520 nm/495 nm TR-FRET ratio is calculated and can be used to determine the IC50 from a dose response curve of the compound. This type of binding assay is analogous to radioligandbased assays, except that it eliminates handling of radioactivity and enables a homogeneous addition-only format.