Hormone · QRFP-family amidated RFamide neuropeptide
26RFa
Also known as QRFP-26; pyroglutamylated RFamide peptide, 26-residue form
The 26-residue QRFP-family peptide used to probe QRFPR activation and precursor-processing relationships.
- Length
- 26 amino acids
- Half-life
- Not well characterised
- Mechanism
- 26RFa activates QRFPR, historically called GPR103, with calcium mobilisation and other G protein-dependent responses observed in recombinant systems. Coupling and apparent potency vary with receptor orthologue, expression level and assay endpoint.
- Studied in
- Receptor-transfected cells, isolated pancreatic islets and rodent hypothalamic models study 26RFa-dependent signalling and neuroendocrine regulation.
About 26RFa
26RFa is a 26-residue neuropeptide belonging to the QRFP family and carrying a C-terminal arginine–phenylalanine amide. It was initially isolated from frog brain and described in 2003, with related sequences subsequently characterised in mammals. The mammalian QRFP precursor also gives rise to the longer peptide 43RFa. The 26-residue form corresponds to the C-terminal segment of 43RFa; its N-terminal glutamine can be cyclised to pyroglutamate, making the exact terminal chemistry an important product specification.
Its principal receptor is QRFPR, a class A G protein-coupled receptor previously designated GPR103. Humans have one recognised QRFPR gene, whereas commonly studied rodent species possess two related receptor genes, complicating direct comparisons between experimental systems. Calcium mobilisation, inositol phosphate accumulation and cyclic AMP measurements provide complementary functional readouts. Investigations also use hypothalamic preparations and pancreatic islets to examine QRFP-family signalling, with receptor expression and peptide processing considered alongside any measured secretory response.
Laboratory notes
- Verify whether the supplied sequence has N-terminal glutamine or pyroglutamate, and confirm C-terminal amidation before comparing datasets.
- Record the receptor species and, for rodent experiments, the receptor paralogue used in each binding or functional assay.
- Use matched molar concentrations when comparing 26RFa with 43RFa; equal peptide masses do not represent equal molecule numbers.
Storage and reconstitution basics: storage guide.
Questions about 26RFa
Are 26RFa and 43RFa unrelated ligands?
No. They belong to the same precursor family, and 26RFa corresponds to the C-terminal 26 residues of 43RFa.
What does QRFPR refer to?
QRFPR is the receptor for QRFP-family peptides. GPR103 is its historical name; rodent receptor paralogues require separate identification in experimental records.
Why specify the N-terminal modification?
Cyclisation of glutamine to pyroglutamate changes the peptide's mass and terminal chemistry, which can affect analytical identification and experimental comparisons. The material is for research use only.
Is 26RFa 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.