C-ANF (4-23)

Also known as cANF(4–23); c-ANF; des[Gln18,Ser19,Gly20,Leu21,Gly22]ANF(4–23)-NH2

A shortened cyclic ANF analogue used to distinguish NPR-C binding and Gi-linked signalling from guanylyl cyclase receptor activity.

Length: 15 amino acids in the commonly used deletion analogue
Half-life: Not well characterised
Mechanism: C-ANF (4-23) preferentially binds natriuretic peptide receptor-C, which lacks an intracellular guanylyl cyclase domain. Depending on the model, NPR-C engagement can influence peptide clearance and Gi-linked signalling, including inhibition of adenylyl cyclase.
Studied in: Receptor-binding assays, NPR-C-expressing cells, cultured vascular smooth-muscle cells and isolated vessels are used to investigate clearance-receptor binding and Gi-dependent signalling.

About C-ANF (4-23)

C-ANF (4-23) belongs to a group of shortened atrial natriuretic factor analogues developed to distinguish natriuretic peptide receptor populations. The commonly used reagent is not simply the uninterrupted fragment spanning residues 4–23. It additionally lacks residues Gln18, Ser19, Gly20, Leu21 and Gly22, giving a 15-residue peptide with a disulphide-linked ring and an amidated C-terminus. Because abbreviated catalogue names can obscure sequence differences, the full sequence and parent species remain essential identifiers.

Its preferential recognition of NPR-C made this analogue an important probe for the receptor historically described as the natriuretic peptide clearance receptor. Unlike NPR-A and NPR-B, NPR-C has no guanylyl cyclase catalytic domain. Its short intracellular region can nevertheless support Gi-linked signalling in suitable cellular contexts. Experiments therefore use C-ANF (4-23) to separate receptor occupancy, peptide internalisation and signalling, while recognising that changing clearance can indirectly alter responses to other natriuretic peptides.

Laboratory notes

Check the full sequence, parent species, deletion pattern and terminal amidation; the name alone does not fully specify the reagent.
Confirm the intramolecular disulphide bond and exclude disulphide-linked oligomers during analytical quality control.
Pair NPR-C binding measurements with cAMP or internalisation assays; cGMP is not a direct NPR-C catalytic readout.

Storage and reconstitution basics: storage guide.

Questions about C-ANF (4-23)

Why is a peptide labelled 4–23 only 15 amino acids long?

The common reagent contains five additional deletions within the 20-residue ANF(4–23) span.

Is C-ANF (4-23) an inert NPR-C blocker?

Not necessarily. It can engage NPR-C-associated signalling and affect clearance, so its behaviour depends on the experimental endpoint.

Can NPR-C directly generate cGMP?

No. NPR-C lacks a guanylyl cyclase domain; any observed cGMP change requires an indirect explanation or involvement of another receptor.

Is C-ANF (4-23) for human use?

No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.

Related research peptides

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