This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
TB-500 is a catalogue name applied to a synthetic peptide related to thymosin beta-4, an actin-binding protein found in most mammalian cells. Suppliers do not use the label consistently: some describe it as the full 43-residue protein, others as a short fragment from the actin-binding region, and others as a related tetrapeptide. Because the name is commercial rather than chemical, two products sold under it may not contain the same molecule. This naming ambiguity is the first point to check in any description of the material.
The most frequently cited identity is a seven-residue fragment with the sequence LKKTETQ, taken from the actin-binding domain of the parent protein. A separate molecule, N-acetyl-seryl-aspartyl-lysyl-proline, often shortened to Ac-SDKP, derives from the same protein's N-terminal region and appears in overlapping literature. Reported molecular masses therefore differ between sources, and a mass value on its own does not establish which fragment is present. Confirmation requires a defined sequence rather than a single number.
Thymosin beta-4 is a 43-residue actin-binding protein found in most mammalian cell types, where it participates in cytoskeletal regulation and cell migration. TB-500 represents only a short fragment of that protein and does not include the remaining residues. Whether the isolated fragment reproduces the full range of activities reported for the intact protein remains an open question. Researchers commonly treat the two as related but distinct entities when comparing results.
Published work involving this sequence spans actin-binding assays, cell-migration studies, wound-healing models, and cardiovascular or musculoskeletal experiments. Much of the biological rationale derives from in vitro systems and animal models, and the number of controlled human studies is small. Reported outcomes vary across preparations, doses, and routes, which complicates comparison between studies. Reviews generally describe the evidence base as preliminary rather than settled. Mechanistic explanations are often proposed by analogy to the parent protein rather than demonstrated directly.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white lyophilized powder | Typical form for short synthetic peptides |
| Solubility class | Freely soluble in water and aqueous buffer | Dissolution aided by gentle mixing, not vigorous shaking |
| Typical storage temperature | −20 °C, desiccated | −80 °C used for long-term holding |
| Common analytical method | Reverse-phase HPLC with UV detection near 214 nm | Identity confirmed separately by mass spectrometry |
| Common synonyms | Thymosin beta-4 fragment; TB4 fragment | Naming varies between suppliers and publications |
Discussion of TB-500 appears in several distinct literatures that rarely cite one another. Peer-reviewed studies usually describe in vitro assays or small animal experiments and are cautious about extrapolation. Veterinary and sports communities circulate anecdotal reports with limited methodological detail. Commercial listings add a third layer, often using the name interchangeably with thymosin beta-4 even though the two molecules differ in size and sequence. Regulatory status varies by country, and the compound is not a licensed medicine in most jurisdictions, so readers comparing sources should check which molecule and which purity each source actually describes.
TB-500 is a synthetic seven-residue peptide whose sequence, LKKTETQ, matches the N-terminal actin-binding region of thymosin beta-4. It is usually supplied in an N-terminally acetylated form, a modification that blocks the free amino terminus and can influence behavior in solution. In the research literature the same sequence appears under several names, including thymosin beta-4 fragment and shortened thymosin beta-4. Because it is a short peptide rather than the full 43-residue parent protein, its measured properties differ from those reported for thymosin beta-4 as a whole, and the two are not interchangeable in experimental design.
Thymosin beta-4 itself is a small, widely expressed protein that sequesters monomeric actin and participates in cell migration, angiogenesis, and tissue repair. Researchers have examined the shortened fragment as a possible mimic of some of these activities, reasoning that the actin-binding motif lies within the first few residues. Binding to monomeric actin has been observed in cell-free systems. Whether the fragment reproduces the broader effects of the full protein in living tissue remains an open question, and findings from animal models are frequently cited without a clear bridge to human physiology.
Thymosin beta-4 was isolated from calf thymus in the early 1980s and later characterised as an abundant intracellular actin-sequestering protein. Interest in short synthetic fragments grew once the actin-binding motif had been mapped to the middle of the sequence. TB-500 came out of that line of work as a truncated analogue rather than a natural isolate, and it is now sold mainly to laboratories. Published studies on the fragment have been largely in vitro or in animal models, and controlled human trials remain sparse, so claims about effects in people rest on extrapolation.
Literature and online discussion often conflate TB-500 with full-length thymosin beta-4, even though the two differ in size and are not interchangeable in analytical terms. The fragment is produced by solid-phase peptide synthesis, and the product is a defined seven-residue chain rather than a biological extract. Because the term is a trade-style label, two vendors may supply materials of the same nominal sequence but different counter-ion content, purity, or water content. Comparisons across studies are therefore difficult unless the exact sequence and purity are reported.
=== Implementing agencies === Bureau of Industry and Security Directorate of Defense Trade Controls Office of Foreign Assets Control U.S. Customs and Border Protection United States Department of Commerce (Export Administration Regulations, EAR) United States Department of Defense United States Department of Energy (nuclear technology) United States Department of Homeland Security (border crossings) United States Department of Justice (including ATF and FBI) United States Department of State (International Traffic in Arms Regulations, ITAR) United States Department of the Treasury
It also requires secondary dressing because wounds can quickly dry up with alginate dressing. Hydrofiber dressing: Made up of sodium carboxymethyl cellulose, hydrofibers can absorb high amounts of wound discharge, forming a gel and preventing skin maceration.
The origins of Cannabis are linked to a Scythian word. The ancient Greeks may have learned of the use of cannabis, which they called κάνναβις, by observing Scythian funerals, during which cannabis was consumed. In Akkadian, cannabis was known as qunubu (𐎯𐎫𐎠𐎭𐏂). The word was adopted in to the Hebrew as qaneh bosem (קָנֶה בֹּשׂם). The Latin term cannabis derived from Greek evolved into Proto-Germanic *xan(a)paz, yielding various Germanic forms (Old Norse hampr, Old English hænep, Old Saxon hanup, Old High German hanaf) and ultimately modern British English "hemp."
=== Clinical trials === Bhatt has served as principal investigator, co-principal investigator, or steering-committee chair for multiple large, multicenter randomized controlled trials examining strategies to reduce cardiovascular events in high-risk patients. His work has included studies of sodium–glucose cotransporter2 (SGLT2) based therapies in patients with diabetes and either heart failure or chronic kidney disease, high-dose eicosapentaenoic acid (icosapent ethyl) in statin-treated patients with elevated triglycerides, intravenous antiplatelet therapy during percutaneous coronary intervention, and intensified oral antiplatelet regimens in patients with stable coronary artery disease and diabetes. His publication record includes work on standardized bleeding definitions for cardiovascular trials, stroke and acute coronary syndrome guidelines, and large outcome studies in diabetes and chronic kidney disease, many of which are highly cited and have been referenced in clinical practice discussions and educational materials in cardiology and stroke medicine.
Sources: en.wikipedia.org
Jasleen Kaur is named as the winner of the 2024 Turner Prize. 4 December Cheshire Constabulary confirms they have interviewed Lucy Letby under caution in prison about further baby deaths. The former prime minister, Boris Johnson, accuses Starmer of misleading the House of Commons and says he should correct the record immediately. This follows an exchange in the House during PMQs when Starmer, answering a question from the leader of the opposition, Kemi Badenoch, said that "two of her predecessors had convictions for breaking the Covid rules". Although the former Conservative prime ministers, Johnson and Rishi Sunak had received fixed penalty notices for breaking COVID-19 regulations, neither had any criminal convictions. 5 December – The Princess of Wales hosts her annual Christmas carol service at Westminster Abbey. 6 December Data published by the Halifax Bank indicates house prices rose by 1.3% in November 2024, marking the fifth consecutive month of growth, with the average house price now estimated at £298,083. Around three million people in Wales and South West England are sent emergency alerts as Storm Darragh approaches the UK. The owners of The Observer confirm the newspaper has been sold to Tortoise Media. The Royal Mint unveils a collector's edition £5 coin featuring Sir Paul McCartney. The UK government announces a £500m contract to build 14 "state-of-the-art" trains at Hitachi's Newton Aycliffe factory, securing the facility's future.
== Acquisitions == Bruker acquisitions include GE NMR Instruments (1992), Siemens AXS (1997), Nonius (2001), MacScience (2002), Vacuumschmelze Hanau (2003), Röntec (2005), SOCABIM (2005), PGT (2005), Keymaster (2006), Quantron (2006), JuWe (2008), SIS (2008), ACCEL (2009), Michrom Bioresources (2011), Skyscan (2012), Prairie Technologies (2013), Oncovision (Preclinical PET imaging business, 2016), Oxford Instruments Superconducting Technology (2016), Hysitron Inc. (2017), XGLab (2017), Luxendo (2017), JPK Instruments (2018), Alicona (2018), PMOD Technologies LLC (2019), Canopy Biosciences (2020), Optimal Group (2022), Neurescence Inc (2022), PhenomeX (2023), MIRO Analytical (majority 2023), NanoString Technologies assets (2024), and ELITechGroup (2024).
== Discovery of PTD-DBM == Professor Kang-Yell Choi and his research team at Yonsei University in South Korea discovered a protein responsible for hair loss in the condition known as androgenetic alopecia. The responsible protein is called CXXC-type zinc finger protein 5 (CXXC5), which acts as a negative regulator for the Wnt/β-catenin pathway, involved in hair regeneration and wound healing. CXXC5 negatively regulates hair growth, and the researchers developed a new substance that promotes hair regeneration by controlling the function of CXXC5. When CXXC5 binds with the Dvl protein, which functions at the upstream of Wnt/β-catenin pathway, it suppresses hair regrowth and hair follicle neogenesis. The observation of CXXC5 overexpression in the bald scalp by Professor Choi’s team led to the development of PTD-DBM, which interferes with the CXXC5-Dvl protein-protein interaction (PPI). By topical application, PTD-DBM enhances hair regrowth as well as neogenesis. The hair growth promoting effect of PTD-DBM is further enhanced when used in combination with a Wnt/β-catenin signaling activator such as VPA, which is generally used as a drug for bipolar disorder and activates the Wnt/β-catenin pathway by inhibition of GSK3β. Currently, topical application of PTD-DBM or its combination with VPA has been used for treatment of hair loss.
=== Myopathies with cores === 'Core myopathies' such as multicore myopathy and central core disease are characterized by sharply-demarcated areas devoid of oxidative enzymes NADH, SDH, and COX, in muscle fibres.
1993/2755) Housing (Right to Buy) (Priority of Charges) (No. 2) Order 1993 (S.I. 1993/2757) Mortgage Indemnities (Recognised Bodies) (No.2) Order 1993 (S.I. 1993/2758) Food Labelling (Amendment) Regulations 1993 (S.I. 1993/2759) Rules of the Supreme Court (Amendment No. 2) 1993 (S.I. 1993/2760) Northern Ireland (Emergency Provisions) Act 1991 (Codes of Practice) (No. 1) Order 1993 (S.I. 1993/2761) Leasehold Reform, Housing and Urban Development Act 1993 (Commencement and Transitional Provisions No. 3) Order 1993 (S.I. 1993/2762) Environmentally Sensitive Areas (Central Borders) Designation Order 1993 (S.I. 1993/2767) Environmentally Sensitive Areas (Stewartry) Designation Order 1993 (S.I. 1993/2768) Charities (Designated Religious Bodies) (Scotland) Order 1993 (S.I. 1993/2774) Plant Breeders' Rights (Amendment) Regulations 1993 (S.I. 1993/2775) Plant Breeders' Rights (Trees, Shrubs and Woody Climbers) Scheme 1993 (S.I. 1993/2776) Plant Breeders' Rights (Tomatoes) Scheme 1993 (S.I. 1993/2777) Plant Breeders' Rights (Miscellaneous Ornamental Plants) (Variation) Scheme 1993 (S.I. 1993/2778) Plant Breeders' Rights (Sainfoin and Birdsfoot Trefoil) Scheme 1993 (S.I. 1993/2779) Plant Breeders' Rights (Herbaceous Perennials) (Variation) Scheme 1993 (S.I. 1993/2780) Plant Breeders' Rights (Quince Rootstocks) Scheme 1993 (S.I. 1993/2781) Finance Act 1993 (Appointed Day No. 2) Order 1993 (S.I. 1993/2782) Local Government Superannuation (South Yorkshire Transport Limited) Regulations 1993 (S.I. 1993/2783) Northern Ireland (Emergency Provisions) Act 1991 (Codes of Practice) (No.
Sources: en.wikipedia.org
TB-500 is a trade-style label for a synthetic peptide connected to thymosin beta-4. It is sold mainly through research-chemical channels and is not a single chemically defined product across suppliers.
Not necessarily. Some vendors use the name for the full 43-residue protein, while others apply it to a short actin-binding fragment or to a related tetrapeptide. The sequence should be confirmed from documentation rather than assumed from the label.
No thymosin beta-4 fragment holds marketing approval as a medicine in major jurisdictions. Material offered for sale is typically labelled for laboratory research only.
No. TB-500 is a short synthetic peptide matching residues 17 to 23 of thymosin beta-4, while the parent protein contains 43 residues. The fragment lacks the rest of the protein sequence, so the two are related but not identical.