Neurokinin A (Substance K) – Neuroscience Peptides

Neurokinin A (NKA) is a member of the classical tachykinins family of peptides which also includes substance P and neurokinin B. These peptides are primarily found in the nervous system where they act as neurotransmitters and neuromodulators. They also play key roles in neuronal inflammation, and high levels of NKA have been linked to poor prognosis of some tumours. The tachykinin peptides are characterised by a common C-terminal sequence, Phe-X-Gly-Leu-Met-NH2, where X represents either an aromatic (Phe, Tyr) or a branched aliphatic (Val, Ile) amino acid. This C-terminal region is thought to be responsible for activating the receptor. The divergent N-terminal region is thought to play a role in determining the receptor subtype selectivity. NKA binds preferentially to the NK2 receptor.