Bioassay Testing¶
Functional Characterization of Peptides¶
Purpose¶
Bioassays confirm that a peptide exhibits the expected biological activity. For research peptides, activity testing validates that the synthetic product functions as intended.
Assay Types¶
| Assay Type | Principle | Example |
|---|---|---|
| Cell-based | Cell proliferation/inhibition | GLP-1 receptor activation |
| Receptor binding | Ligand-receptor affinity | Competitive binding assay |
| Enzyme inhibition | IC₅₀ determination | ACE inhibition |
| cAMP accumulation | Second messenger detection | GLP-1 agonism |
| Calcium flux | Intracellular Ca²⁺ measurement | GPCR activation |
Key Parameters¶
| Parameter | Definition | Typical Range |
|---|---|---|
| EC₅₀ | Half-maximal effective concentration | pM–µM |
| IC₅₀ | Half-maximal inhibitory concentration | pM–µM |
| Kd | Equilibrium dissociation constant | nM–µM |
| Emax | Maximum effect | % of reference |
| Hill coefficient | Slope of response curve | 0.5–2.0 |
Reference Standard Requirements¶
- Known activity: Reference with documented EC₅₀
- Same sequence: Matching primary structure
- Validated purity: ≥95% with full characterization
- Matched salt form: Same counterion/salt form
🔗 Related: Peptide Quality Control Guide | COA Understanding | Mass Confirmation