Other · Lactam-cyclised CRF analogue; CRF1/CRF2 antagonist
Astressin
Also known as —
A 30-residue, lactam-cyclised CRF analogue used to probe signalling through both CRF receptor subtypes.
- Length
- 30 amino acids
- Half-life
- Not well characterised
- Mechanism
- Astressin binds CRF1 and CRF2 receptors and competitively opposes activation by CRF-family agonists. Its constrained peptide scaffold supports receptor binding without the intact N-terminal activation region of CRF.
- Studied in
- Recombinant receptor binding assays, pituitary cultures and rodent neuroendocrine experiments use astressin to assess CRF receptor-dependent signalling.
About Astressin
Astressin emerged from structure–activity work on CRF-derived peptide antagonists. Its scaffold corresponds to CRF residues 12–41 and incorporates D-phenylalanine at position 12, norleucine at positions 21 and 38, and a side-chain lactam bridge between introduced glutamate-30 and lysine-33. These positions use the numbering of full-length CRF. The resulting 30-residue analogue combines N-terminal truncation with conformational restraint and a C-terminal amide characteristic of this antagonist design.
The lactam bridge constrains a region involved in receptor recognition, while replacing methionine with norleucine removes sulphur-containing side chains susceptible to oxidation. Astressin recognises both CRF receptor subtypes and is therefore generally used to establish CRF-receptor involvement rather than assign a response to one subtype. Binding measurements and functional cyclic AMP assays provide complementary evidence, since affinity alone does not establish the extent of antagonism in a particular cellular system.
Laboratory notes
- Confirm lactam connectivity and peptide identity; molecular mass alone does not establish the intended ring topology.
- Validate solubility and recovery in the actual assay buffer before interpreting weak or inconsistent antagonism.
- Include both receptor subtypes or subtype-specific controls when attributing a response to CRF1 or CRF2.
Storage and reconstitution basics: storage guide.
Questions about Astressin
Is astressin a head-to-tail cyclic peptide?
No. Its ring is formed by a side-chain lactam linkage between glutamate-30 and lysine-33, using full-length CRF numbering.
Why does its sequence contain norleucine?
Norleucine replaces methionine at two positions, preserving a hydrophobic side chain while removing the corresponding sulphur oxidation sites.
Does astressin selectively block CRF2?
No. Astressin antagonises both CRF1 and CRF2; it should not be confused with the CRF2-selective analogue astressin 2B.
Is Astressin 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.