Chemical identity
Every value states its source: database, literature, or calculation. Calculated values are not presented as PubChem data.
| Compound class | Monomeric actin-binding peptide (for natural Tβ4) |
|---|---|
| Synonyms | Thymosin β4 · Tβ4 · тимозин бета-4 |
| Formula (Tβ4, 43 residues) | C212H350N56O78SPubChem |
| Mass (Tβ4) | ≈4963 г/мольPubChem |
| PubChem CID | 45382195PubChem |
| Chain length (Tβ4) | 43 а.о.literature |
| Actin-binding motif | LKKTETQliterature |
| Mass of LKKTETQ fragment | ≈847 г/мольcalculatedCalculated from the fragment sequence. Shown for comparison with the full-length molecule; no separate authoritative record is relied on. |
| Sequence | SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGESThe sequence of natural thymosin beta-4, N-acetylated under physiological conditions. Formula and mass were recomputed accounting for acetylation and matched the PubChem record. Material labelled TB-500 does not necessarily correspond to this full sequence. |
What thymosin β4 is
Thymosin β4 is a natural peptide of 43 amino-acid residues present in nearly all mammalian cells. Its best-characterised function is sequestering monomeric G-actin, through which it participates in cytoskeletal regulation, cell migration, and tissue repair.
Published reviews also describe Tβ4 in corneal, skin, and cardiac injury models; clinical studies were conducted in specific indications, but the peptide never became a registered medicine.
What "TB-500" is
"TB-500" is a commercial label that emerged in the research-materials market. No standard ties the name to one molecule: some suppliers sell full-length synthetic thymosin β4 under it, others sell short fragments of its sequence, including the segment described in the literature as the actin-binding site.
Comparing "TB-500" with thymosin β4 in the abstract is therefore meaningless: the question is always which molecule is in a specific batch.
How identity is actually settled
Material identity is established analytically — above all by mass spectrometry, where the measured molecular mass is compared with the value calculated for the declared sequence. A certificate of analysis without identity data does not answer the question "what molecule is this".
For the Moscow Peptides catalogue item, the declared material's identity is stated only after batch documentation has been reviewed. Until then the identity field remains "pending confirmation" — we consider that more honest than a confident claim without data.
References
- Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues — Trends in Molecular Medicine (PMID 16099219), 2005.
- Biological activities of thymosin beta4 defined by active sites in short peptide sequences — The FASEB Journal, 24(7), 2010 (PMID 20179146), 2010.