Other · Amidated opioid tetrapeptide
Endomorphin-2
Also known as EM-2
Phenylalanine-rich opioid tetrapeptide for studying μ-opioid receptor activation and peptide-dependent signalling.
- Length
- 4 amino acids
- Half-life
- Not well characterised
- Mechanism
- Endomorphin-2 selectively activates the μ-opioid receptor (MOR; OPRM1), principally through Gi/o-associated pathways. Receptor activation can inhibit adenylyl cyclase and alter potassium and calcium channel activity in suitable cellular preparations.
- Studied in
- Recombinant receptor assays, spinal cord preparations and rodent sensory-processing models examine its MOR pharmacology, synaptic effects and susceptibility to peptidases.
About Endomorphin-2
Endomorphin-2 is the amidated tetrapeptide Tyr–Pro–Phe–Phe–NH₂, reported alongside Endomorphin-1 in 1997 from bovine brain material. Its two adjacent phenylalanine residues distinguish it from the tryptophan-containing Endomorphin-1. Both peptides exhibit marked preference for the μ-opioid receptor over the δ- and κ-opioid receptor subtypes. A definitive endogenous precursor and complete biosynthetic pathway remain unresolved, an important limitation when interpreting tissue detection or proposed physiological roles.
As a research ligand, Endomorphin-2 supports comparisons between receptor binding and functional efficacy across experimental systems. Investigators measure cyclic AMP responses, G-protein activation, ion-channel modulation and receptor trafficking rather than assuming these readouts are interchangeable. Spinal cord and other neural preparations are used to explore changes in synaptic transmission. Comparisons with Endomorphin-1 help test how a single aromatic-residue substitution influences receptor interactions and enzymatic stability.
Laboratory notes
- Verify Tyr–Pro–Phe–Phe–NH₂ identity and amidation using an appropriate chromatographic and mass-spectrometric method.
- Measure peptide integrity during incubations with serum or tissue extracts rather than assuming nominal concentration equals intact peptide concentration.
- Use matched receptor expression and incubation conditions when comparing Endomorphin-1 and Endomorphin-2.
Storage and reconstitution basics: storage guide.
Questions about Endomorphin-2
Does Endomorphin-2 contain tryptophan?
No. Its sequence is Tyr–Pro–Phe–Phe–NH₂; Endomorphin-1 contains tryptophan at position 3.
Which receptor is its principal target?
The μ-opioid receptor, encoded by OPRM1, is its principal characterised receptor target.
Can immunostaining alone establish its presence in tissue?
Immunostaining indicates antibody recognition but may be affected by cross-reactivity. Orthogonal chemical identification, such as validated LC–MS/MS, provides stronger evidence for the intact peptide.
Is Endomorphin-2 for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.