EC50
EC50 — The half-maximal effective concentration, representing the concentration of a compound that produces 50% of its maximum possible biological response.
What Is EC50?
EC50 (half-maximal effective concentration) is the concentration of a peptide agonist that produces 50% of the maximum possible effect. It is the primary measure of peptide potency in functional assays (cell signaling, enzyme activation, biological response), complementing IC50 for inhibitory measurements and Kd/Ki for binding affinity.
Interpretation
- Lower EC50 = higher potency: A peptide with EC50 = 1 nM is 100x more potent than one with EC50 = 100 nM
- Distinct from efficacy: A partial agonist can have a low EC50 (high potency) but low Emax (low efficacy)
- Assay-dependent: EC50 values differ between assay formats (cAMP, calcium, reporter gene) due to receptor reserve and signal amplification
Frequently Asked Questions
What is EC50?
The half-maximal effective concentration, representing the concentration of a compound that produces 50% of its maximum possible biological response.
Why is EC50 important in peptide research?
EC50 is a fundamental concept in pharmacology as it relates to peptide science. It directly influences experimental design, compound characterization, and the reliability of research outcomes across biochemistry and molecular biology disciplines.