Compound record

Substance P

SP; neurokinin P

Linear C-terminal amidation

Sequence

RPKPQQFFGLM-NH2

RPKPQQFFGLM

Length 11 residues
Formula C63H98N18O13S elemental composition
Molecular weight 1,347.63 g/mol · average mass
CAS number 33507-63-0 registry ID
PubChem CID 36511 PubChem ID

Length counts residues; formula and mass are the stored free-base values from cited sources; CAS and PubChem identify the substance in public registries. More detail: length & peptide bonds, molecular weight

Structure & modifications

Linear undecapeptide; C-terminal methionine amide.

Notes

Substance P is an undecapeptide tachykinin (from protachykinin-1) acting mainly at the NK1 receptor in nociception and neurogenic inflammation.

The conserved C-terminal motif FXGLM-NH2 is required for activity. On this record that chemistry appears as a methionine amide; the N-terminus is free arginine.

ItemValue
1-letter coreRPKPQQFFGLM
DisplayRPKPQQFFGLM-NH2
Length11
CAS / PubChem33507-63-0 / 36511

Search with the 1-letter core, but reconcile mass using the amide in display notation. NKA and NKB share the C-terminal motif yet are separate sequences.

Primary-source references

  • PubChem CID 36511 — substance P
  • UniProt P20366 (protachykinin-1)
  • Chang M.M., Leeman S.E., Niall H.D. Amino-acid sequence of substance P. Nat. New Biol. 1971.

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