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TB-500
The structure of TB-500. Identifiers
IUPAC name
(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-acetamido-4-methylpentanoyl]amino]-6-aminohexanoyl]amino]-6-aminohexanoyl]amino]-3-hydroxybutanoyl]amino]-4-carboxybutanoyl]amino]-3-hydroxybutanoyl]amino]-5-amino-5-oxopentanoic acid CAS Number
885340-08-9 PubChem CID
62707662 ChemSpider
72380051 UNII
QHK6Z47GTG Chemical and physical data Formula C38H68N10O14 Molar mass 889.018 g·mol−1 3D model (JSmol)
Interactive image
SMILES
C[C@H]([C@@H](C(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H]([C@@H](C)O)C(=O)N[C@@H](CCC(=O)N)C(=O)O)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(C)C)NC(=O)C)O
InChI
InChI=1S/C38H68N10O14/c1-19(2)18-27(42-22(5)51)35(58)44-23(10-6-8-16-39)32(55)43-24(11-7-9-17-40)33(56)47-30(20(3)49)36(59)45-25(13-15-29(53)54)34(57)48-31(21(4)50)37(60)46-26(38(61)62)12-14-28(41)52/h19-21,23-27,30-31,49-50H,6-18,39-40H2,1-5H3,(H2,41,52)(H,42,51)(H,43,55)(H,44,58)(H,45,59)(H,46,60)(H,47,56)(H,48,57)(H,53,54)(H,61,62)/t20-,21-,23+,24+,25+,26+,27+,30+,31+/m1/s1
Key:ADKDNDYYIZUVCZ-ZQNQAVPYSA-N
TB-500 (Ac-LKKTETQ) is a synthetic heptapeptide that corresponds to the N-acetylated active fragment (amino acids 17–23)[1] of the endogenous signalling factor thymosin beta-4.[2] It is claimed to increase muscle growth and accelerate wound healing and tissue repair,[3] reduce inflammation, and improve flexibility.[4][5]
It has been encountered as a designer drug mainly in racehorses,[6] but is also prohibited for use by athletes in competition by the World Anti-Doping Agency, and is classified as a prescription medicine in some jurisdictions such as Australia and New Zealand.[7]
N-acetylated LKKTETQ (Ac-LKKTETQ) and several of its metabolites can be detected in equine urine and plasma following administration of TB-500 using liquid chromatography–mass spectrometry, with metabolite profiling enabling identification of peptide-derived products in biological samples.[8]
Ac-SDKP Adamax BPC-157 CJC-1295 Epidermal growth factor Link-N Mechano growth factor PEPITEM Thymalfasin
↑ Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P (September 2012). "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". Drug Testing and Analysis. 4 (9): 733–738. doi:10.1002/dta.1402. PMID 22962027. ↑ Van Troys M, Dewitte D, Goethals M, Carlier MF, Vandekerckhove J, Ampe C (January 1996). "The actin binding site of thymosin beta 4 mapped by mutational analysis". The EMBO Journal. 15 (2): 201–210. doi:10.1002/j.1460-2075.1996.tb00350.x. PMC 449934. PMID 8617195. ↑ Rahaman KA, Muresan AR, Min H, Son J, Han HS, Kang MJ, et al. (March 2024). "Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro". Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences. 1235 124033. doi:10.1016/j.jchromb.2024.124033. PMID 38382158. ↑ Davison G, Brown S (2013). "The potential use and abuse of thymosin β-4 in sport and exercise science". Journal of Sports Sciences. 31 (9): 917–918. doi:10.1080/02640414.2013.771958. PMID 23421910. ↑ Ying Y, Lin C, Tao N, Hoffman RD, Shi D, Chen Z, et al. (2023). "Thymosin β4 and Actin: Binding Modes, Biological Functions and Clinical Applications". Current Protein & Peptide Science. 24 (1): 78–88. doi:10.2174/1389203724666221201093500. PMID 36464872. ↑ Kwok WH, Ho EN, Lau MY, Leung GN, Wong AS, Wan TS (March 2013). "Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry". Analytical and Bioanalytical Chemistry. 405 (8): 2595–2606. doi:10.1007/s00216-012-6697-9. PMID 23318763. ↑ "Classification of Unscheduled Peptides. Submission to the Medicines Classification Committee" (PDF). Medsafe. New Zealand Medicines and Medical Devices Safety Authority. June 2025. ↑ Ho EN, Kwok WH, Lau MY, Wong AS, Wan TS, Lam KK, et al. "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". Journal of Chromatography. A. 1265: 57–69. doi:10.1016/j.chroma.2012.09.043. PMID 23084823.