[His11] Substance P is a full-length Substance P analog in which the native C-terminal methionine is replaced by histidine. The remainder of the 11-residue Substance P sequence is preserved.

The substitution changes the terminal residue from a hydrophobic sulfur-containing amino acid to an imidazole-containing residue with substantially different polarity and ionization behavior, making the peptide useful for C-terminal structure–activity studies.

Product Information

Changing C-Terminal Hydrophobicity and Ionization

The C-terminal residues of Substance P contribute strongly to its interaction with tachykinin receptors. Replacing Met11 with His makes a substantial physicochemical change at this position.

Methionine is predominantly hydrophobic, whereas the imidazole side chain of histidine can participate in hydrogen bonding and changes protonation state near physiological pH. The analog therefore provides a direct way to investigate how C-terminal side-chain chemistry influences Substance P behavior.

Unlike [Nle11] Substance P, His11 is not a conservative hydrophobic replacement for Met11. We therefore recommend measuring receptor activity directly in the intended assay rather than assuming native Substance P potency.

Research Applications

[His11] Substance P can support Substance P structure–activity studies, C-terminal residue comparisons, tachykinin receptor research and investigations of how terminal residue polarity influences peptide behavior.

Frequently Asked Questions

Which residue is changed?

Native Met11 is replaced by His.

Does this peptide contain methionine?

No. The C-terminal methionine has been replaced, eliminating Met11 oxidation.

Is His11 a conservative replacement for Met11?

No. Histidine has substantially different polarity and ionization properties, making this analog more suitable for structure–activity research than as a chemically equivalent substitute for native Substance P.

Research Use Only.