Neurokinin A (NKA), also known as Substance K or Neuromedin L, is a 10-residue endogenous tachykinin derived from the TAC1 precursor. Its mature sequence is His-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met-NH₂.

Among the endogenous mammalian tachykinins, Neurokinin A is the principal ligand associated with NK2 receptor pharmacology.

Product Information

The Principal Endogenous NK2 Ligand

All three major mammalian tachykinins display some receptor overlap, but curated pharmacology gives the typical human NK2 potency order as Neurokinin A > Neurokinin B >> Substance P.

NKA is therefore particularly useful as the endogenous reference agonist when synthetic NK2-selective ligands or antagonists are evaluated.

Full-Length Sequence and C-Terminal Pharmacophore

Residues 4-10 form the active fragment DSFVGLM-NH₂, while His-Lys-Thr provides the native N-terminal extension. Comparing the intact decapeptide with NKA (4-10) allows the contribution of this extension to be examined directly.

Experimental Considerations

NKA contains Met10, so oxidation state should be considered when receptor potency or stability is quantified. Tachykinin receptor overlap also makes receptor-defined controls preferable to assigning responses from ligand identity alone.

Related products can be explored in our Neurotransmitters & Neuropeptides collection.

Frequently Asked Questions

Is Substance K the same as Neurokinin A?

Yes. Substance K and Neuromedin L are established synonyms for Neurokinin A.

Which receptor is its principal endogenous target?

NK2R is the principal receptor associated with Neurokinin A.

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