Catestatin

Also known as CST; chromogranin A-derived catestatin

A 21-residue chromogranin A fragment studied for nicotinic receptor modulation and interactions with microbial membranes.

Length: 21 amino acids in the canonical human fragment
Half-life: Not well characterised
Mechanism: Catestatin inhibits neuronal nicotinic acetylcholine receptor-mediated responses non-competitively, reducing stimulus-evoked catecholamine secretion in chromaffin-cell assays. Its cationic, amphipathic properties also support membrane interactions examined in antimicrobial model systems.
Studied in: Chromaffin cells, recombinant nicotinic receptor systems, microbial cultures and model lipid membranes are used to study catestatin-dependent secretion and membrane activity.

About Catestatin

Catestatin was identified in 1997 during studies of chromogranin A fragments that inhibit catecholamine release from chromaffin cells. The canonical human peptide corresponds to chromogranin A residues 352–372 and has the sequence SSMKLSFRARAYGFRGPGPQL. It is rich in basic and hydrophobic residues, contains no cysteine and does not require disulphide bonds. Proteolytic processing of the parent granule protein determines whether this sequence is released as a discrete fragment.

Its defining experimental activity is non-competitive inhibition of nicotinic cholinergic stimulation in secretory-cell preparations. This distinguishes receptor-linked effects from a general block of all secretion pathways, which requires separate testing. Catestatin is also examined in bacterial growth assays and membrane biophysics because its charge and amphipathic character favour interactions with lipid surfaces. Sequence variants and terminal modifications can change activity, so conclusions should remain tied to the exact construct tested.

Laboratory notes

Confirm sequence and terminal chemistry; naturally occurring sequence variants and modified fragments can have different assay profiles.
Control ionic strength and medium composition in microbial and membrane assays, as these can alter cationic peptide activity.
Compare nicotinic stimulation with a receptor-bypassing depolarisation control, and measure viability to exclude nonspecific suppression of secretion.

Storage and reconstitution basics: storage guide.

Questions about Catestatin

Is catestatin a competitive acetylcholine antagonist?

Its defining inhibitory action is described as non-competitive. It should not be assumed to act by simple competition at the acetylcholine-binding site.

Does catestatin require an insulin-like folded structure?

No. The canonical human fragment is a single 21-residue chain without cysteine. Its membrane-associated conformation can differ from its conformation in aqueous solution.

Do antimicrobial assay results establish a nicotinic receptor mechanism?

No. Microbial and model-membrane experiments investigate distinct interactions, often involving peptide charge and lipid composition, rather than neuronal nicotinic receptor signalling.

Is Catestatin 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.