The short version of thymosin beta-4 fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-12-19 and is reviewed periodically as new material appears.
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.
Research interest in thymosin beta-4 fragments centres on actin sequestration, cell migration and tissue repair models. Most published work uses cultured cells or animal wound and cardiac preparations, and findings are generally described as preliminary. No fragment of this protein has been approved as a therapeutic product by major regulators. Reviews of the field note inconsistent dosing, delivery routes and outcome measures across studies, which complicates direct comparison. The material is best understood as a laboratory reagent with an active but unresolved research literature.
TB-500 is a synthetic peptide whose sequence corresponds to a short fragment near the N-terminus of thymosin beta-4, a small protein present in most mammalian cells. The fragment is commonly cited as containing the actin-binding region of the parent molecule, which is why it appears in laboratory work on cell migration and tissue repair. Suppliers distribute it as a lyophilised powder intended for research use. Its identity is defined by amino acid sequence and by the presence of an acetyl group on the N-terminal residue.
Full-length thymosin beta-4 consists of roughly forty-three amino acids and ranks among the more abundant small proteins in the cytoplasm. The fragment is much shorter, so it cannot reproduce every function attributed to the intact molecule. In cell culture, short actin-binding motifs can interfere with filament dynamics and cell movement, but such observations come from controlled experiments rather than from whole-animal work. Whether a truncated fragment produces the same effects as the parent protein remains an open question.
Interest in the peptide grew during the 2000s and 2010s, when studies of tendon and ligament injuries in horses reported changes in lesion size after treatment. Those reports circulated widely outside the scientific literature and shaped much of the current online discussion. Subsequent reviews noted inconsistent study design, small groups, and a shortage of independent replication. Popular descriptions often blur the line between the fragment, the complete protein, and unrelated growth factors, which complicates comparisons across sources.
| 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 |
Dry powder is commonly held at minus twenty degrees Celsius, with some suppliers recommending lower temperatures for long-term archival storage. Once dissolved, solutions are typically kept cold and protected from light, since aqueous peptide solutions can lose integrity through hydrolysis or oxidation over time. Stability data specific to this fragment are limited in the public literature, and much of the guidance comes from general peptide handling practice rather than from controlled degradation studies. Users therefore treat stated shelf lives as approximate rather than fixed.
Identity and purity are normally assessed with reversed-phase high-performance liquid chromatography, paired with mass spectrometry to confirm molecular mass. A certificate of analysis reports a purity percentage, usually derived from chromatographic peak area, but that figure does not by itself prove a correct sequence or the absence of counterions. Independent verification may include amino acid analysis or peptide mapping. Batch-to-batch variation is a documented concern in the research chemical market, and the gap between a quoted purity value and actual peptide content can be substantial when the material is a salt or retains residual water.
Lyophilized peptide arrives as a dry cake that should stay sealed until use. Reconstitution is generally performed with sterile water or a buffered solution, and the resulting liquid should be handled gently to limit mechanical stress. Repeated freeze-thaw cycles are widely described as harmful to short peptides, so dividing a reconstituted batch into single-use portions is a common practice. Laboratories also record the solvent, concentration, and date of preparation on the vial label to keep later measurements traceable.
TB-500 is a short synthetic peptide sold under a trade name rather than a systematic chemical name. Suppliers usually describe it as a fragment of thymosin beta-4 and ship it as a lyophilised powder intended for laboratory use. Because the label is commercial, the exact sequence attributed to it is not fully consistent across catalogues, and some listings present a seven-residue peptide while others describe related fragments of similar length. It is not an approved medicine in any major jurisdiction, and it is handled as a research chemical.
Thymosin beta-4 itself is a natural peptide of 43 residues found in many cell types and body fluids. Its best-characterised function is binding and sequestering actin monomers, which influences cytoskeletal dynamics. The sequence most often associated with TB-500, LKKTETQ, corresponds to part of that actin-binding region. A different fragment, Ac-SDKP, is also derived from the same parent peptide and is studied in its own right, which is one reason discussions of thymosin fragments can become confusing. The two are structurally distinct and are not interchangeable.
Interest in the fragment grew during the 1990s and 2000s, when it moved from laboratory work into sports and supplement markets. Anti-doping bodies added thymosin beta-4 fragments to prohibited lists, and a small number of adverse analytical findings have been reported in competition testing. Published controlled human trials remain scarce. Most mechanistic evidence comes from cell culture and animal models, and those studies examine endpoints such as cell migration, wound closure and inflammation markers. That evidence supports research interest but does not establish clinical benefit, and broad regenerative claims should be read as unverified.
=== 1973 to 2009 === Hanmi was founded in 1973 by Lim Sung-ki, who was a pharmacist. It was originally named Lim, Sung-ki Pharmaceutical Co., but it was quickly changed to Hanmi Pharmaceutical. The company originally started selling Trimethoprim/sulfamethoxazole powder, and would expand to produce Cephalosporin antibiotics in 1985 and injectable Ceftriaxone antibiotics in 1987. By 1988 the company was listed in the Korea Exchange. Hanmi started selling drugs in China in 1996. In 1994, the company began developing Cyclosporin. The company broke the ₩100,000,000,000 barrier in sales in 1997. The company began moving into the European market in 1998. The company still was developing new drugs, with Paclitaxel in 2000, Itraconazole tablets in 2001, 24-hour controlled-release Nifedipine tablets and a new salt form of Amlodipine in 2004, and an anti-obesity drug using sibutramine mesilate in 2007. Hanmi and Crystal Genomics formed a strategic partnership in 2008.
The batmen were skilled at presenting and maintaining several police uniform 'dress orders' worn throughout any given day, all of which were expected to be immaculate at all times. The responsibilities of these Caucasian police officers, once trained, were broadly the same as those of UK police officers. Black officers engaged in operational police work worked alongside their white colleagues on investigations and patrols, necessarily acting as interpreters with the indigenous population, as well as patrolling alone and conducting their own crime investigations or as otherwise directed. Black "ground coverage" officers acted as undercover plainclothes intelligence gatherers in both rural and urban areas. A district (rural) police station with a strength of anything from a dozen to forty personnel was often required to 'fly the flag' over an area comprising several hundred sq. kilometres. On 18 December 1978, Equitation Squad 14/78–the first multi-racial recruit squad-began training at Morris Depot in Salisbury (now Harare). Prior to this date, Black recruits were trained at Tomlinson Depot, while White officers were trained at Morris Depot. Included in this historic intake was Patrol Officer Sinclair Roberts, the first mixed-race Police Officer accepted to the Force, 89 years after it was founded.
In 2006 and 2007, a series of studies provided arguably the first documented examples of de novo gene birth that did not involve overprinting. These studies were conducted using the accessory gland transcriptomes of Drosophila yakuba and Drosophila erecta and they identified 20 putative lineage-restricted genes that appeared unlikely to have resulted from gene duplication. Levine and colleagues identified and confirmed five de novo candidate genes specific to Drosophila melanogaster and/or the closely related Drosophila simulans through a rigorous approach that combined bioinformatic and experimental techniques. Since these initial studies, many groups have identified specific cases of de novo gene birth events in diverse organisms. The first de novo gene identified in yeast, BSC4 gene was identified in S. cerevisiae in 2008. This gene shows evidence of purifying selection, is expressed at both the mRNA and protein levels, and when deleted is synthetically lethal with two other yeast genes, all of which indicate a functional role for the BSC4 gene product. Historically, one argument against the notion of widespread de novo gene birth is the evolved complexity of protein folding. Interestingly, Bsc4 was later shown to adopt a partially folded state that combines properties of native and non-native protein folding. In plants, the first de novo gene to be functionally characterized was QQS, an Arabidopsis thaliana gene identified in 2009 that regulates carbon and nitrogen metabolism.
Sources: en.wikipedia.org
The following list contains only notable graduates and former students of Columbia College, the undergraduate liberal arts division of Columbia University, and its predecessor, from 1754 to 1776, King's College. For a full list of individuals associated with the university as a whole, see the List of Columbia University people. An asterisk (*) indicates a former student who did not graduate.
Labcorp ($14.00B revenue in 2020) IQVIA ($11.35B revenue in 2020) PPD, Inc. ($4.68B revenue in 2020) Syneos Health ($4.41B revenue in 2020) Charles River Laboratories ($2.92B revenue in 2020) ICON PLC ($2.79B revenue in 2020) Parexel ($2.44B revenue in 2017) Wuxi Apptec ($1.01B revenue in 2017) Medpace ($0.92B revenue in 2020)
These strongly electrophilic NAIs allow for reactions with a wide range of nitrogen nucleophiles, including hindered and electron-deficient amines. An added benefit of the use of NMI as the base, due to its low pKa(H2O) of 7, is that the epimerization of labile stereogenic centers is minimized. The reaction by-products have high water solubility, facilitating reaction workup and isolation.
Between 400 and 1200 AD, Arab traders introduced opium to China, and to India by 700 AD. The physician Muhammad ibn Zakariya al-Razi of Persian origin ("Rhazes", 845–930 CE) maintained a laboratory and school in Baghdad, and was a student and critic of Galen; he made use of opium in anesthesia and recommended its use for the treatment of melancholy in Fi ma-la-yahdara al-tabib, "In the Absence of a Doctor", a home medical manual directed toward ordinary citizens for self-treatment if a doctor was not available. The renowned Andalusian ophthalmologic surgeon Abu al-Qasim al-Zahrawi ("Abulcasis", 936–1013 CE) relied on opium and mandrake as surgical anesthetics and wrote a treatise, al-Tasrif, that influenced medical thought well into the 16th century. The Persian physician Abū 'Alī al-Husayn ibn Sina ("Avicenna") described opium as the most powerful of the stupefacients, in comparison to mandrake and other highly effective herbs, in The Canon of Medicine. The text lists medicinal effects of opium, such as analgesia, hypnosis, antitussive effects, gastrointestinal effects, cognitive effects, respiratory depression, neuromuscular disturbances, and sexual dysfunction. It also refers to opium's potential as a poison. Avicenna describes several methods of delivery and recommendations for doses of the drug. This classic text was translated into Latin in 1175 and later into many other languages and remained authoritative until the 19th century. Şerafeddin Sabuncuoğlu used opium in the 14th-century Ottoman Empire to treat migraine headaches, sciatica, and other painful ailments.
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.
It is a synthetic peptide based on a short sequence near the start of thymosin beta-4. It is supplied as a research chemical rather than as a licensed pharmaceutical product.