Neuropeptides

The neuropeptides here are short peptides first isolated from nervous or related tissue, and they are structurally diverse: substance P is an amidated tachykinin, neurotensin carries an N-terminal pyroglutamate, and bombesin, first isolated from frog skin, is an amidated 14-residue peptide that also begins with pyroglutamate. The opioid peptides have their own family page.

Members compared

Calculated from each structure

Peptide	Residues	Formula	Monoisotopic mass (Da)	Charge, pH 7	pI	Termini
Substance P	11	C63H98N18O13S	1,346.7281	3.0	—	free amine; amide
Neurotensin	13	C78H121N21O20	1,671.9097	1.0	9.98	pyroglutamate (no free amine); free acid
Bombesin	14	C71H110N24O18S	1,618.8151	1.2	—	pyroglutamate (no free amine); amide

Sequences and relationships

Each member's sequence in three-letter code, and how it relates to Substance P, worked out position by position from the structures. Members with no entry in the last column are not direct sequence relatives of Substance P.

Relationship to Substance P

Peptide	Sequence	Relationship
Substance P	H-Arg-Pro-Lys-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH2	Reference sequence
Neurotensin	H-Pyr-Leu-Tyr-Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-Leu-OH	—
Bombesin	H-Pyr-Gln-Arg-Leu-Gly-Asn-Gln-Trp-Ala-Val-Gly-His-Leu-Met-NH2	—

Shared analytical features

The sequence-specific variants from each member's entry, counted across the family: what an HPLC or mass spectrometry result for these peptides is most often read against.

Variants by number of members

Variant	Members
Asparagine deamidation	2 of 3: Neurotensin, Bombesin
C-terminal amide	2 of 3: Substance P, Bombesin
Glutamine deamidation	2 of 3: Substance P, Bombesin
Methionine oxidation	2 of 3: Substance P, Bombesin
Tryptophan oxidation	1 of 3: Bombesin

Every member can also carry the synthesis-related variants common to all synthetic peptides, described in How synthetic peptides are made.

Sources & Further Reading

1. Prohaska T, Irrgeher J, Benefield J, Böhlke JK, Chesson LA, Coplen TB, et al. Standard atomic weights of the elements 2021 (IUPAC Technical Report). Pure and Applied Chemistry 2022;94(5):573–600. doi:10.1515/pac-2019-0603
2. Wang M, Huang WJ, Kondev FG, Audi G, Naimi S. The AME 2020 atomic mass evaluation (II). Tables, graphs and references. Chinese Physics C 2021;45(3):030003. doi:10.1088/1674-1137/abddaf
3. Rice P, Longden I, Bleasby A. EMBOSS: the European Molecular Biology Open Software Suite. Trends in Genetics 2000;16(6):276–277. doi:10.1016/S0168-9525(00)02024-2
4. Pace CN, Vajdos F, Fee L, Grimsley G, Gray T. How to measure and predict the molar absorption coefficient of a protein. Protein Science 1995;4(11):2411–2423. doi:10.1002/pro.5560041120
5. Kyte J, Doolittle RF. A simple method for displaying the hydropathic character of a protein. Journal of Molecular Biology 1982;157(1):105–132. doi:10.1016/0022-2836(82)90515-0
6. Meija J, Coplen TB, Berglund M, Brand WA, De Bièvre P, Gröning M, et al. Isotopic compositions of the elements 2013 (IUPAC Technical Report). Pure and Applied Chemistry 2016;88(3):293–306. doi:10.1515/pac-2015-0503
7. Roepstorff P, Fohlman J. Letter to the editors: proposal for a common nomenclature for sequence ions in mass spectra of peptides. Biomedical Mass Spectrometry 1984;11(11):601. doi:10.1002/bms.1200111109
8. Biemann K. Contributions of mass spectrometry to peptide and protein structure. Biomedical and Environmental Mass Spectrometry 1988;16(1–12):99–111. doi:10.1002/bms.1200160119
9. Geiger T, Clarke S. Deamidation, isomerization, and racemization at asparaginyl and aspartyl residues in peptides. Succinimide-linked reactions that contribute to protein degradation. Journal of Biological Chemistry 1987;262(2):785–794. doi:10.1016/S0021-9258(19)75855-4
10. Manning MC, Chou DK, Murphy BM, Payne RW, Katayama DS. Stability of protein pharmaceuticals: an update. Pharmaceutical Research 2010;27(4):544–575. doi:10.1007/s11095-009-0045-6
11. D'Hondt M, Bracke N, Taevernier L, Gevaert B, Verbeke F, Wynendaele E, et al. Related impurities in peptide medicines. Journal of Pharmaceutical and Biomedical Analysis 2014;101:2–30. doi:10.1016/j.jpba.2014.06.012

Cosmic Peptides. (2026, October 25). Neuropeptides. Cosmic Peptides Research Library. Retrieved October 26, 2026, from https://cosmicpeptides.com/research/peptides/families/neuropeptide

@misc{cosmicpeptides_research_peptides_families_neuropeptide,
  author       = {{Cosmic Peptides}},
  title        = {Neuropeptides},
  howpublished = {Cosmic Peptides Research Library},
  year         = {2026},
  month        = oct,
  url          = {https://cosmicpeptides.com/research/peptides/families/neuropeptide},
  urldate      = {2026-10-26},
  note         = {Last reviewed 2026-10-25}
}

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