$422.00 - $422.00
[D-Pro2,D-Trp6,8,Nle10]-Neurokinin B is a multiply modified Neurokinin B analog containing D-Pro2, D-Trp6, D-Trp8 and Nle10 substitutions.
Unlike native NKB agonists, this peptide was characterized as a competitive antagonist of Neurokinin B responses. In a classical guinea pig ileum assay, it produced a reported pA2 of 5.5 against NKB while showing little antagonism of Substance P or Neurokinin A responses.
Product Information
| Product Name | [D-Pro2,D-Trp6,8,Nle10]-Neurokinin B |
| Catalog No. | AS2236 |
| CAS No. | 109212-72-8 |
| Sequence | Asp-D-Pro-His-Asp-Phe-D-Trp-Val-D-Trp-Leu-Nle-NH2 |
| Peptide Length | 10 residues |
| Molecular Formula | C67H87N15O14 |
| Molecular Weight | Approximately 1326.5 Da |
| Key Modifications | D-Pro2; D-Trp6; D-Trp8; Nle10 |
| C-Terminus | Amidated |
| Pharmacological Profile | Competitive NKB / NK3 antagonist |
| Reported pA2 | 5.5 in guinea pig ileum |
| Purity Options | Crude to 98% |
D-Amino-Acid Substitutions Change NKB Pharmacology
The analog replaces three residues with D-amino acids and substitutes the terminal Met with Nle. D-residues can substantially alter the preferred peptide conformation and reduce recognition by some proteases, while Nle removes the oxidation-sensitive sulfur atom present in methionine.
The combined modification pattern produces pharmacology that differs fundamentally from native Neurokinin B. This peptide should therefore be treated as an antagonist tool rather than as a stabilized version of the natural agonist.
Competitive Antagonism of Neurokinin B Responses
In classical guinea pig ileum experiments, the peptide competitively antagonized Neurokinin B with a reported pA2 of 5.5. The same study found that it did not significantly antagonize responses to Substance P or Neurokinin A.
We recommend keeping the historical pA2 tied to its original tissue assay. It should not be presented as a universal human TACR3 affinity value because receptor species, signaling system and assay design can influence apparent antagonist potency.
Research Applications
The peptide can support NKB antagonist studies, NK3 receptor pharmacology, tachykinin receptor differentiation and structure–activity investigations involving D-amino-acid substitution.
It is particularly useful when an experiment requires a peptide-based antagonist rather than a modern non-peptide NK3 inhibitor.
Frequently Asked Questions
Is this peptide an NK3 agonist or antagonist?
It is best characterized as a competitive antagonist of Neurokinin B responses in classical pharmacological studies.
What is the reported pA2?
A pA2 value of approximately 5.5 was reported against NKB in guinea pig ileum.
Does it also block Substance P or Neurokinin A?
The original comparative study reported no significant antagonism of Substance P or Neurokinin A responses under the same assay conditions.
Why is Nle present at position 10?
Norleucine replaces methionine and removes the sulfur-containing side chain, eliminating methionine oxidation at this position.