Compound monograph
TB-500
Analytical studies have identified an N-terminally acetylated heptapeptide with the residue sequence LKKTETQ in material labeled TB-500. The designation alone does not establish the complete molecular identity of another preparation.
01
Identity & nomenclature
Analytical studies have identified an N-terminally acetylated heptapeptide with the residue sequence LKKTETQ in material labeled TB-500. The designation alone does not establish the complete molecular identity of another preparation.
TB-500 is a product designation whose use does not uniquely specify a molecular structure. This dossier concerns the acetylated LKKTETQ referent identified in analytical literature. It does not establish the identity or composition of a commercial preparation.
Declared aliases and development codes: N-acetyl-thymosin beta-4 (17-23).
02
Molecular properties
| One-letter sequence | LKKTETQ |
|---|---|
| Three-letter sequence | Ac–Leu–Lys–Lys–Thr–Glu–Thr–Gln |
The residue sequence LKKTETQ corresponds to positions 17-23 of mature human thymosin beta-4 and positions 18-24 of UniProt P62328, whose initiator methionine is removed. The fragment's N-terminal acetyl modification is attached to leucine, rather than to the serine that begins the mature parent.
03
Structural characteristics
Terminal features: N-terminal acetylation at Leu1.
04
Molecular targets & mechanisms
05
Analytical considerations
The retrieved registry representations disagree on molecular formula and molecular weight. Their reported properties are retained as conflicting observations; no settled formula or average molecular weight is assigned here. A calculation for a specified terminal structure characterizes that structure and does not resolve the source disagreement.
06
Verified bibliography
- Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential.
Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P
Drug testing and analysis · 2012-09-07 · Journal Article
current - Doping control analysis of TB-500, a synthetic version of an active region of thymosin β₄, in equine urine and plasma by liquid chromatography-mass spectrometry.
Ho EN, Kwok WH, Lau MY, Wong AS, Wan TS, Lam KK, Schiff PJ, Stewart BD
Journal of chromatography. A · 2012-09-23 · Journal Article
current - TB500/TB1000 and SGF1000: A scientific approach for a better understanding of misbranded and adulterated drugs.
Delcourt V, Garcia P, Chabot B, Barnabé A, Bouscarel M, Loup B, Popot MA, Bailly-Chouriberry L
Drug testing and analysis · 2022-12-23 · Journal Article
current
10
Methodology & citation verification
Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.
Read the full methodology →