BULKGLP RESEARCH LIBRARY
BPC-157 vs TB-500: Molecular Identity
Published
BPC-157 and material labeled TB-500 are different peptides; a useful comparison starts with the exact amino-acid sequence, not the product nickname.
At a glance
- BPC-157 is a synthetic 15-residue peptide: GEPPPGKPADDAGLV.
- An original TB-500 analysis identified the seven-residue fragment Ac-LKKTETQ.
- Full-length thymosin beta-4 has 43 residues and is a separate molecular identity.
Compare the specified molecules
| Identity | Length | Specification to confirm |
|---|---|---|
| BPC-157 | 15 residues | GEPPPGKPADDAGLV and declared terminal groups |
| Ac-Tβ4(17–23) | 7 residues | Ac-LKKTETQ; N-terminal acetylation |
| Thymosin beta-4 | 43 residues | Full sequence and terminal modifications |
The BPC-157 sequence is documented in an original mass-spectrometric characterization study. Esposito and colleagues identified Ac-LKKTETQ in a product named TB-500 using chromatography and mass spectrometry, then synthesized the fragment for confirmation. Full-length thymosin beta-4 is described separately in structural work on its actin complex.
Why the TB-500 name needs clarification
The name alone does not tell the laboratory whether a supplied material is the acetylated fragment or full-length thymosin beta-4. Request the stated sequence, terminal chemistry and expected molecular mass before assigning it to an assay. The prefix “Ac” indicates an acetyl group; it changes the molecular specification.
A result obtained with the full-length molecule cannot automatically be assigned to its fragment. Sequence length and modification can affect interactions, chromatographic behavior and assay response. Likewise, a comparison does not establish equivalent activity or suitability for a particular experiment.
Match the lot to the specification
Review the BPC-157 listing and TB-500 listing without inferring either lot’s sequence from the name. Match the received lot to its report, expected mass and any available sequence evidence. The COA interpretation guide explains why HPLC peak area purity, molecular identity and measured peptide content require separate checks.