TB-500 and Thymosin Beta-4
TB-500 is a product name whose molecular meaning needs checking. Researchers identified a short acetylated fragment of thymosin beta-4 in one preparation sold under that name. To decide whether a paper applies to another vial, compare the actual sequence and modifications first. [1]
Full-length thymosin beta-4, its fragment and a TB-500 label
| Record | What it identifies |
|---|---|
| Full-length thymosin beta-4 research | The complete peptide construct used in that experiment |
| Published TB-500 preparation analysis | The specific material analysed by those investigators |
| A supplier's TB-500 label | A commercial name requiring a documented molecular match |
Esposito and colleagues used chromatography and high-resolution mass spectrometry on their TB-500 sample. They identified Ac-LKKTETQ, corresponding to residues 17–23 of human thymosin beta-4 with an acetyl group at the fragment’s N-terminus. That finding identifies the material analysed in 2012. [1]
Why the distinction changes the interpretation
Full-length thymosin beta-4 features in a different experiment. Xue and colleagues resolved structures of thymosin beta-4 bound to actin. One structure showed two peptide helices contacting different faces of actin. A paper about those contacts does not establish the binding behaviour of an isolated seven-residue fragment. [2]
Malinda and colleagues studied thymosin beta-4 in a rat full-thickness wound model and separately measured keratinocyte migration in a laboratory assay. Both the material and the model differ from an uncharacterised TB-500 blend. Human treatment outcomes were outside those experiments. [3]
Resolve the supplier identity in writing
Ask the supplier to name the sequence and terminal groups, then ask which result on the offered lot supports that assignment. If the specification says “fragment” but cites only research on full-length thymosin beta-4, request the fragment-specific evidence before using the citation.
The names and identifiers guide explains the reconciliation process. Mass spectrometry explains why a measured ion and its interpretation need method context.
When the report arrives, use the Certificate of Analysis guide to check its material description and lot connection before interpreting the results.
The co-formulated product needs both identities
On the BPC-157 5 mg + TB-500 5 mg listing, the TB-500 amount is nominal. Ask for both component identities, their quantity bases and a method that resolves each in the mixture. The BPC-157 and TB-500 comparison shows which fields belong to each constituent.
Record the TB-500 identity as unresolved until the specification and applicable lot evidence agree. Neither the 2012 sample nor a paper about full-length thymosin beta-4 can fill that gap.
Continue the material check
| Resource | Why open it |
|---|---|
| Thymosin Beta-4 and Actin Binding | Read actin-binding evidence for the actual thymosin construct. |
| Repair and Tissue Research Peptides | Browse the tissue-research category and its distinct identity questions. |
| Compound Index | Find another molecular profile without confusing it with a vial. |
| Sterility, Endotoxin and Bioburden Are Three Different Things | Separate sterility, endotoxin and bioburden evidence. |
Sources and scope
- Esposito et al. (2012). TB-500 fragment characterisation. Drug Testing and Analysis.Chemical analysis of one preparation. The authors identify the N-terminally acetylated 17–23 fragment.
- Xue et al. (2014). Thymosin β4, profilin and actin exchange. PNAS.Structural and biochemical work on thymosin beta-4, actin and profilin. The structures concern the construct used in this experiment.
- Malinda et al. (1999). Thymosin β4 in a wound model. Journal of Investigative Dermatology.Rat full-thickness wounds and a separate keratinocyte migration assay. The experiments used thymosin beta-4.