The Growth and differentiation factor 15 (GDF15):GFRAL[Biotinylated] Inhibitor Screening Assay Kit is designed for screening and profiling inhibitors of GDF15:GFRAL signaling. The key to this kit is the high sensitivity of detection of biotin-labeled GFRAL by streptavidin-HRP. First, GDF15 is coated on a 96-well plate. Next, GDF15 is co-incubated with inhibitor(s) and biotin-conjugated GFRAL on the plate. Finally, the plate is treated with streptavidin-HRP followed by addition of a colorimetric HRP substrate. The reaction is quenched, and absorbance is measured on a plate reader.