TB-500

{{cs1 config|name-list-style=vanc|display-authors=6}} {{Infobox drug | image = TB-500_structure.png | image_class = skin-invert-image | width = 260 | caption = The structure of TB-500. | tradename = | pregnancy_category = | routes_of_administration = | class = | ATC_prefix = | ATC_suffix = | ATC_supplemental =  | legal_status =  | bioavailability = | protein_bound = | metabolism = | metabolites = | onset = | elimination_half-life = | duration_of_action = | excretion =  | CAS_number = 885340-08-9 | PubChem = 62707662 | IUPHAR_ligand = | DrugBank = | ChemSpiderID = 72380051 | UNII = QHK6Z47GTG | KEGG = | ChEBI = | ChEMBL = | NIAID_ChemDB = | PDB_ligand =  | IUPAC_name = <nowiki>(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</nowiki> | C = 38 | H = 68 | N = 10 | O = 14 | StdInChI = 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 | StdInChIKey = ADKDNDYYIZUVCZ-ZQNQAVPYSA-N | 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 }}

'''TB-500''' ('''Ac-LKKTETQ''') is a synthetic heptapeptide that corresponds to the N-acetylated active fragment (amino acids 17–23)<ref>{{cite journal | vauthors = Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P | title = 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 | journal = Drug Testing and Analysis | volume = 4 | issue = 9 | pages = 733–738 | date = September 2012 | pmid = 22962027 | doi = 10.1002/dta.1402 }}</ref> of the endogenous signalling factor thymosin beta-4.<ref>{{cite journal | vauthors = Van Troys M, Dewitte D, Goethals M, Carlier MF, Vandekerckhove J, Ampe C | title = The actin binding site of thymosin beta 4 mapped by mutational analysis | journal = The EMBO Journal | volume = 15 | issue = 2 | pages = 201–210 | date = January 1996 | doi = 10.1002/j.1460-2075.1996.tb00350.x | pmid = 8617195 | pmc = 449934 }}</ref> It is claimed to increase muscle growth and accelerate wound healing and tissue repair,<ref>{{cite journal | vauthors = Rahaman KA, Muresan AR, Min H, Son J, Han HS, Kang MJ, Kwon OS | title = 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 = Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences | volume = 1235 | article-number = 124033 | date = March 2024 | pmid = 38382158 | doi = 10.1016/j.jchromb.2024.124033 }}</ref> reduce inflammation, and improve flexibility.<ref>{{cite journal | vauthors = Davison G, Brown S | title = The potential use and abuse of thymosin β-4 in sport and exercise science | journal = Journal of Sports Sciences | date = 2013 | volume = 31 | issue = 9 | pages = 917–918 | pmid = 23421910 | doi = 10.1080/02640414.2013.771958 }}</ref><ref>{{cite journal | vauthors = Ying Y, Lin C, Tao N, Hoffman RD, Shi D, Chen Z, Gao J | title = Thymosin β4 and Actin: Binding Modes, Biological Functions and Clinical Applications | journal = Current Protein & Peptide Science | date = 2023 | volume = 24 | issue = 1 | pages = 78–88 | pmid = 36464872 | doi = 10.2174/1389203724666221201093500 }}</ref>

It has been encountered as a designer drug mainly in racehorses,<ref>{{cite journal | vauthors = Kwok WH, Ho EN, Lau MY, Leung GN, Wong AS, Wan TS | title = Doping control analysis of seven bioactive peptides in horse plasma by liquid chromatography-mass spectrometry | journal = Analytical and Bioanalytical Chemistry | volume = 405 | issue = 8 | pages = 2595–2606 | date = March 2013 | pmid = 23318763 | doi = 10.1007/s00216-012-6697-9 }}</ref> 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.<ref>{{cite web | title = Classification of Unscheduled Peptides. Submission to the Medicines Classification Committee. | date = June 2025 | url = https://www.medsafe.govt.nz/profs/class/Agendas/Agen74/5.7Peptides.pdf | work = Medsafe | publisher = New Zealand Medicines and Medical Devices Safety Authority }}</ref>

== References == {{Reflist}}

Category:Heptapeptides