Receptor binding assays
Radioligand or fluorescent displacement assays quantify affinity (Kd, Ki). Useful when comparing analogues with the same target.
Functional readouts
cAMP, calcium flux, β-arrestin recruitment, or downstream phosphorylation assays tell you whether binding actually translates into signalling.
Stability and degradation
Time-course HPLC of peptide in serum, plasma or buffer at 37°C reveals half-life and degradation products.
Frequently asked questions
Which assay first?+
Usually a functional readout — binding without signalling has limited interpretive value.