[Nle11] Substance P is a full-length Substance P analog in which the native C-terminal methionine is replaced by norleucine. The modification removes sulfur from residue 11 while maintaining a hydrophobic aliphatic side chain of similar dimensions.

This makes [Nle11] Substance P particularly useful when researchers require a Substance P agonist scaffold without the oxidation liability associated with Met11.

Product Information

Removing the Met11 Oxidation Site

Methionine contains a thioether that can oxidize to methionine sulfoxide during synthesis, storage or repeated solution handling. Norleucine has a similarly sized hydrophobic side chain but contains no sulfur.

The Met11 → Nle substitution therefore eliminates one common source of chemical heterogeneity in Substance P preparations.

We consider this modification most valuable for experiments involving extended storage, repeated handling or direct comparison of peptide lots. The substitution specifically addresses methionine oxidation; it should not be interpreted as protection against every proteolytic or chemical degradation pathway.

Research Applications

[Nle11] Substance P can support NK1 receptor studies, Substance P structure–activity experiments, peptide stability comparisons and experiments where oxidation of the native Met11 residue could complicate interpretation.

A related double-substituted molecule, [Tyr8,Nle11] Substance P, additionally modifies the aromatic residue at position 8.

Frequently Asked Questions

Why replace Met11 with norleucine?

Norleucine removes the sulfur atom responsible for methionine oxidation while retaining a hydrophobic aliphatic side chain.

Can [Nle11] Substance P undergo methionine oxidation?

No. The peptide contains no Met11 residue, so methionine oxidation at the C-terminus is eliminated.

Does Nle make the peptide completely degradation-resistant?

No. The modification removes one oxidation pathway but does not prevent cleavage or modification elsewhere in the peptide.

Research Use Only.