TB-500 is a label that needs an explicit molecular definition. A published analysis identified Ac-LKKTETQ in the material it examined, while Novum’s standalone reports describe a TB-500 project reference without printing its complete sequence.
Three related names, three distinct descriptions
Esposito and colleagues identified N-terminally acetylated LKKTETQ in the TB-500-labelled sample they examined. The seven residues correspond to positions 17–23 of mature thymosin beta-4. Low and colleagues described the full-length parent as a 43-residue peptide with an acetyl-blocked amino terminus.Esposito et al. (2012) (opens in a new tab)Low, Hu and Goldstein (1981) (opens in a new tab)
| Description | Structural distinction |
|---|---|
| Thymosin beta-4 | Full-length 43-residue parent; N-terminal acetylation |
| LKKTETQ | Seven-residue sequence within the parent |
| Ac-LKKTETQ | That fragment with its own N-terminal acetyl group |
The Ac prefix records a covalent acetyl group. Preserve it with the sequence; it is not a salt designation. The parent numbering identifies a location in the longer chain, while LKKTETQ is the complete fragment sequence in this comparison.Esposito et al. (2012) (opens in a new tab)
What is known about the standalone material
| Field | Documented position |
|---|---|
| Material name | TB-500 project reference; synthetic freeze-dried peptide material |
| Identity test | LC-HRMS comparison with a qualified reference |
| Full sequence and terminal modifications | Not printed in either supplied standalone report |
| CAS number, molecular formula and molecular weight | Not assigned here: the reference structure is not fully disclosed |
Ask for the complete chemical specification of the qualified reference: amino-acid sequence, terminal groups, other covalent modifications and chemical form. The answer should identify the same reference and lot as the report. An identity conformity result does not itself disclose these missing structural fields.Supplied TB-500 5 mg report — lot TB5-06-SQQ (opens in a new tab)Supplied TB-500 10 mg report — lot TB5-07-UPB (opens in a new tab)
The supplied 10 mg BPC-157 + TB-500 blend report explicitly writes Ac-LKKTETQ. That statement belongs to that blend report. It does not specify the sequence of the standalone 5 mg or 10 mg TB-500 material.Supplied BPC-157 + TB-500 10 mg report — lot BPT-42-7LP (opens in a new tab)Supplied TB-500 5 mg report — lot TB5-06-SQQ (opens in a new tab)Supplied TB-500 10 mg report — lot TB5-07-UPB (opens in a new tab)
Product and certificate documents
Sources and further detail
- Esposito et al. (2012) (opens in a new tab)
Existing dossier author manuscript, especially PDF page 7: fragment sequence, acetylation and numbering only.
- Low, Hu and Goldstein (1981) (opens in a new tab)
Full-length thymosin beta-4 residue count and N-terminal acetylation; retained from the parent-peptide reference.
- Supplied TB-500 5 mg report — lot TB5-06-SQQ (opens in a new tab)
Supplied report: identity wording and analytical fields. Results concern the named sample and lot; this is document transcription, not independent authentication.
- Supplied TB-500 10 mg report — lot TB5-07-UPB (opens in a new tab)
Supplied report: identity wording and analytical fields. Results concern the named sample and lot; this is document transcription, not independent authentication.
- Supplied BPC-157 + TB-500 10 mg report — lot BPT-42-7LP (opens in a new tab)
Supplied report: identity wording and analytical fields. Results concern the named sample and lot; this is document transcription, not independent authentication.
Identity sources and supplied documents checked for this revision on 3 October 2026. Report transcription is separate from independent authentication. This article has not undergone independent scientific peer review.