[Cys3,6,Tyr8,Pro10]-Substance P is a conformationally constrained Substance P analog containing a Cys3–Cys6 disulfide bridge together with Tyr8 and Pro10 substitutions.

The cyclic peptide was developed through tachykinin structure–activity studies and is recognized as a selective NK1 receptor agonist.

Product Information

Disulfide Cyclization Restricts Peptide Conformation

The Cys3–Cys6 disulfide bridge reduces the conformational freedom available to the N-terminal and central portion of the peptide.

This is fundamentally different from a linear residue substitution. Cyclization changes the ensemble of conformations presented to the receptor and can help identify bioactive conformational requirements.

Tyr8 and Pro10 Further Shape the NK1 Pharmacophore

Tyr8 preserves an aromatic side chain while introducing a phenolic hydroxyl group. Pro10 restricts backbone geometry near the C-terminal region.

Classical tachykinin SAR work identified both this cyclic analog and the related Pro9 cyclic analog as selective NK1 agonists.

We recommend verifying disulfide formation by mass spectrometry and, where required, orthogonal analytical methods because the oxidized cyclic peptide is chemically distinct from the corresponding reduced dithiol form.

Research Applications

The peptide can support NK1 receptor activation studies, cyclic peptide SAR, conformational constraint experiments and tachykinin receptor subtype research.

Frequently Asked Questions

Is the peptide cyclic?

Yes. Cys3 and Cys6 form an intramolecular disulfide bond.

Is it an NK1 agonist?

Yes. Classical tachykinin studies identify it as a selective NK1 receptor agonist.

Why verify the disulfide state?

The reduced and oxidized forms have different structures and can behave differently in receptor studies.

Research Use Only.