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[β-Ala8]-Neurokinin A (4-10) is a synthetic heptapeptide analog of NKA(4-10) in which Gly8 is replaced by β-alanine.
This single backbone modification produces one of the best-characterized peptide tools for selective NK2 receptor activation and has been used extensively in receptor binding, smooth-muscle and in vivo tachykinin studies.
Product Information
| Product Name | [β-Ala8]-Neurokinin A (4-10) |
| Catalog No. | AS2527 |
| CAS No. | 122063-01-8 |
| Sequence | Asp-Ser-Phe-Val-β-Ala-Leu-Met-NH2 |
| Short Sequence | DSFV-βA-LM-NH2 |
| Peptide Length | 7 residues |
| Molecular Formula | C35H56N8O10S |
| Molecular Weight | Approximately 780.9 Da |
| Key Substitution | Gly8 → β-Ala |
| C-Terminus | Amidated |
| Pharmacological Profile | Potent selective NK2 receptor agonist |
| Purity Options | Crude to 98% |
Why β-Ala8 Changes NK2 Selectivity
β-Alanine differs from α-amino acids because the amino group is separated from the carboxyl group by an additional methylene. Replacing Gly8 therefore changes peptide backbone spacing rather than simply replacing one side chain with another.
Early structure–activity studies reported that NK2 affinity increased by nearly one order of magnitude relative to NKA(4-10), while activity at NK1- and NK3-associated systems decreased.
Conformational studies further showed that β-Ala8 changes the turn geometry of the NKA fragment, providing a structural explanation for its characteristic NK2-selective pharmacology.
Quantitative NK2 Binding Data
Tritiated [β-Ala8]-NKA(4-10) has also been used as an NK2 radioligand. In hamster urinary bladder membranes, the labeled peptide bound a single class of high-affinity sites with a reported Kd of approximately 1.8 ± 0.2 nM.
We recommend keeping this Kd associated with the hamster bladder membrane system. Binding affinity at recombinant human TACR2 can differ with receptor expression and assay conditions.
Research Applications
[β-Ala8]-NKA(4-10) is suitable for NK2 receptor activation studies, radioligand competition experiments, smooth-muscle pharmacology, urinary bladder models, gastrointestinal studies and tachykinin structure–activity research.
For stability-sensitive experiments, the retained C-terminal methionine should be monitored for oxidation.
Frequently Asked Questions
Is [β-Ala8]-NKA(4-10) selective for NK2?
Yes. It is one of the classical peptide agonists used to define NK2 receptor responses.
What is changed relative to NKA(4-10)?
Gly8 is replaced by β-alanine.
What binding affinity has been reported?
A Kd of approximately 1.8 nM was reported for a tritiated form in hamster urinary bladder membranes.
Is this the same peptide as [Ala5,β-Ala8]-NKA(4-10)?
No. [Ala5,β-Ala8]-NKA(4-10) contains an additional Ser5 → Ala substitution.