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Peptide identity reference

Identity data for the compounds that Vortex Research publishes lot reports for: sequence, terminal modifications, molecular formula, average molecular weight, monoisotopic mass, residue count, PubChem CID and CAS number. Every PubChem value is stored with the query URL that returned it, and every peptide formula and mass is recomputed from the sequence and checked against PubChem. The lot reports themselves are on the Vortex Research lab report page and in the companion lot report dataset.

Records

Avg MW (PubChem) is PubChem's value as PubChem rounds it; Avg MW (computed) uses the same IUPAC 2005 element values PubChem uses. Monoisotopic mass is recomputed by scripts/mass.js and agrees with PubChem's MonoisotopicMass to better than 0.0001 Da on every row. "Match" means the recomputed formula is identical to PubChem's and both masses agree within 0.05 Da, or the only difference is PubChem's display rounding (explained in the row's notes).

TB-500 and thymosin beta-4

These names are often used for different molecules. Thymosin beta-4 (Tβ4, INN timbetasin) is a 43-residue chain with an acetylated N-terminus, C212H350N56O78S, about 4963 g/mol, CAS 77591-33-4. In PubChem, the name TB-500 resolves to Ac-LKKTETQ-OH, the seven-residue N-acetylated stretch matching residues 17-23 of that chain, C38H68N10O14, about 889 g/mol, CAS 885340-08-9. Some supplier listings pair the name TB-500 with the full Tβ4 identity. Only a mass measurement shows which molecule a material contains, so this dataset keeps them as two rows.

Download

• peptide_identity.csv: one row per record, lists separated by ; , notes by |
• peptide_identity.json: the same data with every query URL, related PubChem records, variants and a meta block
• Source, field definitions and build scripts: github.com/vrtx-research/peptide-identity-reference

Verify a row

Each row's sources block holds the exact PubChem PUG REST URLs used. To check one by hand, request the properties for its CID and compare formula and masses:

https://pubchem.ncbi.nlm.nih.gov/rest/pug/compound/cid/9941957/property/MolecularFormula,MolecularWeight,MonoisotopicMass/JSON

Resolve a CAS number to its CID the same way (/compound/name/137525-51-0/cids/JSON). Resolve by CAS rather than by short name: the bare name "KPV" returns an unrelated compound in PubChem, and "GHK-Cu" returns six records, one of them copper-free. If anything differs, PubChem is the record. Please open an issue so the row can be corrected.

Notes, variants and flags

Lines starting "FLAG (PubChem data, not this row)" describe inconsistencies inside PubChem records that this dataset does not use.

BPC-157

H-Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val-OH

• PubChem synonyms for this record include trifluoroacetate-salt names. The formula and masses are for the free peptide without counter-ions.
• Background: What is BPC-157, BPC-157 and TB-500.

TB-500

Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH

• Naming: "TB-500" is a market name, not a systematic one. PubChem CID 62707662 (synonyms TB-500 and TB500; CAS 885340-08-9) is Ac-LKKTETQ-OH, the N-acetylated heptapeptide matching residues 17-23 of the mature 43-residue thymosin beta-4 chain (numbering as in UniProt P62328 after removal of the initiator methionine).
• Some supplier listings attach the full thymosin beta-4 identity (CAS 77591-33-4, C212H350N56O78S, about 4963 g/mol) to the name TB-500. That is a different molecule; it has its own row (thymosin-beta-4).
• The same heptapeptide without the N-acetyl group is a separate PubChem record, CID 10169788 (C36H66N10O13), 42.01 Da lighter. See variants.
• Variant: LKKTETQ without the N-acetyl group (PubChem title: Fequesetide). PubChem CID 10169788, C36H66N10O13, monoisotopic 846.4811. Recomputed formula matches: yes.
• Background: TB-500 vs thymosin beta-4, BPC-157 and TB-500.

Thymosin beta-4 (Tβ4)

Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser-OH

• Sequence source: UniProt P62328 (TYB4_HUMAN). The translated precursor starts with an initiator methionine that is removed; the mature chain is 43 residues (precursor positions 2-44) with an N-acetylated Ser1. Residue numbers in this dataset follow the mature chain.
• UniProt also lists natural acetyl-lysine and phosphorylation sites. The formula and masses here are for the unmodified chain apart from the N-terminal acetyl group, which is what PubChem CID 16132341 records.
• PubChem has two records with this formula: CID 16132341 (title Timbetasin, the INN; stereocentres defined; CAS 77591-33-4) and CID 45382195 (title Thymosin Beta 4, stereocentres not defined, no CAS listed). PubChem name lookup "Thymosin beta-4" returns CID 45382195. CID 16132341 is used because the CAS number resolves to it.
• Not the same molecule as TB-500 (row tb-500). Ac-LKKTETQ is residues 17-23 of this chain.
• Resolved: Main record average MW. PubChem reports 4963 (rounded to 0 decimal places); computed 4963.44. The 0.44 Da difference is PubChem's display rounding: the formulas are identical and the monoisotopic masses agree to 1.3e-7 Da.
• Background: TB-500 vs thymosin beta-4.

GHK (free tripeptide)

H-Gly-His-Lys-OH

• This is the copper-free tripeptide. PubChem's synonym list for this record also carries the names "GHK-Cu" and "Copper Peptide", so a name lookup for "GHK-Cu" returns this copper-free record among its results. Match the CID to the material: copper complex = row ghk-cu.
• The CAS-format string 1227510-36-2 appears in this record's synonym list but not in PubChem's CAS section; 49557-75-7 is used.
• PubChem name lookup "GHK" returns 2 CIDs (73587, 342538); 73587 is the one used.
• Background: GHK-Cu peptide.

GHK-Cu (copper complex)

H-Gly-His-Lys-OH

• CAS 89030-95-5 resolves to PubChem CID 71587328 (title Prezatide copper), which draws the 1:1 complex as a cation: GHK minus one proton plus Cu, overall charge +1, C14H23CuN6O4+.
• PubChem holds several other GHK-copper records that differ in copper ratio and protonation (see related_pubchem_records), so "GHK-Cu" has no single formula or molecular weight. The value that applies to a solid material depends on the copper ratio, protonation state and counter-ions, which the lot report or supplier should state.
• The copper-free tripeptide is row ghk (CID 73587, CAS 49557-75-7).
• FLAG (PubChem data, not this row): CID 71587328 is drawn as the singly deprotonated cation (C14H23CuN6O4+), while several of its synonyms, e.g. "Copper, (N2-(N-glycyl-L-histidyl)-L-lysinato(2-))-", name the doubly deprotonated neutral complex (C14H22CuN6O4, the formula of CID 165429100). The two differ by one hydrogen (1.008 Da).
• PubChem name lookup "GHK-Cu" returns 6 CIDs (139035031, 9831891, 73587, 71587328, 133697840, 165429100); 71587328 is the one used.
• Background: GHK-Cu peptide.

KPV

H-Lys-Pro-Val-OH

• PubChem name lookup "KPV" returns CID 13294447, which is an unrelated compound (2-oxo-5-phenylpentanoic acid, C11H12O3). The tripeptide Lys-Pro-Val is CID 125672, which CAS 67727-97-3 resolves to. Do not resolve this compound by the bare name "KPV".
• KPV matches residues 11-13 of alpha-MSH. In alpha-MSH itself the C-terminal valine is amidated (UniProt P01189, "Valine amide"); the PubChem KPV record and its synonyms (H-Lys-Pro-Val-OH, "alpha-MSH (11-13) (free acid)") describe the free acid, which is what this row gives.

MOTS-c

H-Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg-OH

• Length: UniProt A0A0C5B5G6 (gene MT-RNR1) and PubChem CID 146675088 both give 16 residues, MRWQEMGYIFYPRKLR. No source reviewed for this dataset gives a different length.
• CAS 1627580-64-6 resolves to three PubChem records: the free peptide (CID 146675088, used here) and two salt records. FLAG (PubChem data, not this row): CID 172641109 is titled "Mots-C acetate", but its formula (C107H155F9N28O28S2) equals the free peptide plus three trifluoroacetic acid units, so the title and formula of that record disagree. Not used.

Selank

H-Thr-Lys-Pro-Arg-Pro-Gly-Pro-OH

• Selank is the tuftsin sequence TKPR (PubChem CID 156080, H-Thr-Lys-Pro-Arg-OH) extended by Pro-Gly-Pro.
• Variant names exist. "N-Acetyl Selank" is PubChem CID 133082488 (Ac-TKPRPGP-OH, C35H59N11O10, +42.01 Da; C-terminal free acid per its IUPAC name). The name "N-Acetyl Selank Amidate" has no PubChem record (lookup returns not found), so no formula is given for it here. A material sold under a variant name is a different molecule from the Selank in this row.
• Variant: N-acetyl Selank (Ac-TKPRPGP-OH). PubChem CID 133082488, C35H59N11O10, monoisotopic 793.4446. Recomputed formula matches: yes.

Semax

H-Met-Glu-His-Phe-Pro-Gly-Pro-OH

• Semax is ACTH residues 4-7 (MEHF) extended by Pro-Gly-Pro, as PubChem's synonym "ACTH (4-7), Pro-Gly-Pro-" states.
• Variant names exist. "N-Acetyl Semax Amidate" is PubChem CID 172638603 (Ac-MEHFPGP-NH2, C39H54N10O10S, 854.37 Da monoisotopic). The shorter name "N-Acetyl Semax" resolves to that same amidated record in PubChem, so the two names are not distinguished there. A material sold under a variant name is a different molecule from the Semax in this row.
• Variant: N-acetyl Semax amidate (Ac-MEHFPGP-NH2). PubChem CID 172638603, C39H54N10O10S, monoisotopic 854.3745. Recomputed formula matches: yes.

NAD+

• Not a peptide: no sequence or residue count. mass.js computes masses from the formula; the formula itself is checked by an independent fragment sum (ADP-ribose, CID 33576, plus nicotinamide, CID 936, minus water).
• PubChem name lookup "NAD+" returns four CIDs: 5892 (Nadide, C21H27N7O14P2, CAS 53-84-9), 5893 (protonated cation, C21H28N7O14P2+), 15938971 (anion, C21H26N7O14P2-) and 10897651 (a second record with the same formula as 5892). CID 5892 is used because CAS 53-84-9 resolves to it.
• PubChem's CAS section also lists 64417-72-7 for this record (1 source entry, against 12 for 53-84-9); 53-84-9 is used.

5-Amino-1MQ

• Not a peptide: no sequence or residue count. Formula checked by an independent fragment sum (5-aminoquinoline, CID 11911, plus a methyl group on the ring nitrogen).
• PubChem name lookup "5-Amino-1MQ" returns no record. The cation is CID 950107 (CAS 685079-15-6, C10H11N2+, 159.21). The iodide salt is CID 66522933 (CAS 42464-96-0, C10H11IN2, 286.11). Which CAS number and molecular weight apply to a material depends on its counter-ion.
• FLAG (PubChem data, not this row): the iodide record's synonym list also contains "5-Amino-1-methylquinolinium chloride", which does not match that record's formula (iodide). Not used.

Cite

Vortex Research (2026). Vortex Research peptide identity reference [Data set]. Zenodo. https://doi.org/10.5281/zenodo.23578942

Archived on Zenodo (DOI 10.5281/zenodo.23578942); each release has its own version DOI.

Research use only. Vortex Research materials are sold for in-vitro laboratory research by qualified researchers. Not for human or veterinary use. Not a drug, dietary supplement or cosmetic. Statements have not been evaluated by the FDA. This page holds identity data only: what each molecule is, not what it does.