The short version of RP-HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-21 and is reviewed periodically as new material appears.
The fragment most often associated with the name carries the sequence Ac-LKKTETQ, matching residues 17 through 23 of thymosin beta-4. That region holds the actin-binding motif responsible for much of the parent protein's biochemical activity. Apart from N-terminal acetylation the peptide is unmodified and contains no disulfide bonds, so it shows little ordered secondary structure in solution. Full-length thymosin beta-4 is instead a 43-residue polypeptide of roughly 4.9 kDa found widely across mammalian cell types.
Material sold under this label typically arrives as a freeze-dried powder in a sealed vial with a certificate of analysis. Such certificates usually report reversed-phase chromatography purity plus a mass confirmation, and stated purities commonly sit between 95 and 99 percent. Counter-ion identity, residual trifluoroacetate, water content, and peptide net weight are separate specifications that a certificate may or may not include. A purity figure alone does not establish sequence identity, so independent mass verification remains the practical check.
Detection in biological samples relies on mass spectrometry, typically liquid chromatography coupled to tandem mass spectrometry after peptide extraction and enrichment. Intact peptides can also be confirmed by high-resolution mass measurement together with fragmentation data. Detection windows in urine are short because the peptide is degraded by proteases and cleared quickly, and concentrations are low. Many jurisdictions treat the compound as a prohibited substance in sport, grouped with peptide hormones and related factors, while it is not an approved therapeutic product. Identity and purity statements therefore rest on certificates of analysis, ideally issued by an independent laboratory.
Material is normally supplied as a lyophilised powder in a sealed vial. The powder is hygroscopic, so exposure to humid air leads to water uptake, caking and gradual loss of the fluffy texture that indicates a good freeze-dry. Vials are best kept sealed with desiccant, protected from light and stored cold. Letting a cold vial warm to room temperature before opening reduces condensation on the contents. Purity is normally reported from a chromatographic run, and that figure applies to the batch as tested rather than to the vial after repeated opening.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | ≈889 Da for the 7-residue fragment | Full-length thymosin beta-4 is ≈4.9 kDa; catalogs differ |
| Appearance | White to off-white powder | Hygroscopic; weight shifts with residual moisture |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffers; poorly soluble in nonpolar solvents |
| Typical storage temperature | −20 °C, desiccated, protected from light | Once rehydrated, short-term holding at 2-8 °C |
| Typical analytical method | Reversed-phase HPLC with mass spectrometry | Purity by UV absorbance; identity by ESI-MS or MALDI-TOF |
The seven-residue chain carries several polar and charged side chains, so it dissolves readily in water and in aqueous buffers near neutral pH. No cysteine is present, so disulphide formation is not a concern and reducing agents are unnecessary. Dilute ammonium hydroxide or acetonitrile-water mixtures are sometimes used for stock solutions when initial dissolution is slow. Strongly alkaline conditions and prolonged contact with oxidising agents are avoided because they can modify lysine-containing stretches, and haze in solution usually signals incomplete dissolution or aggregated material.
Identity and purity are checked with reversed-phase high-performance liquid chromatography, which separates the target sequence from truncated or deletion analogues, and with mass spectrometry, which confirms the expected molecular mass. Amino acid analysis and peptide mapping give orthogonal confirmation but are used less often outside specialist laboratories. Counter-ion content varies: material purified on trifluoroacetic acid gradients retains trifluoroacetate, and ion exchange can convert the salt form. Residual water and solvent are measured by Karl Fischer titration or thermogravimetric analysis, and any purity figure should be read together with the method used to obtain it.
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.
Identity and purity are checked with chromatographic and mass spectrometric methods. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities, while mass spectrometry confirms the expected molecular mass. A certificate of analysis may report a purity percentage, but the laboratory should still verify the material independently. Common quality concerns include truncated sequences, deamidation, oxidation, and residual solvents from synthesis. Because TB-500 is short, some impurities can differ from the target by only a few mass units.
Reconstitution practices affect downstream measurements. The dry powder is typically dissolved in sterile water or a suitable aqueous buffer, then mixed gently rather than vortexed at high speed. Visible particles or cloudiness suggest incomplete dissolution or contamination and should be investigated. For long-term storage, aliquots should be labeled with concentration, solvent, and date. Open questions include how different buffers alter peptide conformation and whether specific container materials adsorb the peptide. Those variables can change apparent concentration in assays even when the chemical identity is correct.
Lyophilized TB-500 is hygroscopic and should be kept dry before use. The usual storage recommendation for the solid is -20 °C, protected from light and moisture. Once dissolved, the peptide is less stable, and repeated freeze-thaw cycles can promote aggregation or degradation. Laboratories often divide a reconstituted solution into single-use aliquots and store them at -80 °C. Exact stability limits depend on buffer, pH, and concentration, so published data do not define a single universal condition.
==== Research and traditional medicine ==== Preliminary research indicates that the phytochemicals, betulin and possibly other triterpenes, are active in Episalvan gel and wound healing properties of birch bark. Over centuries, birch bark was used in traditional medicine practices by North American indigenous people for treating superficial wounds by applying bark directly to the skin. Splints made with birch bark were used as casts for broken limbs in the 16th century.
Brenner has developed targeted, quantitative analysis of the NAD+ metabolome and made fundamental contributions to NAD metabolism including discovery of nicotinic acid riboside-dependent NAD synthesis, elucidating the mechanism of synthesis of nicotinic acid adenine dinucleotide phosphate, and discovering multiple conditions in which NAD metabolism is dysregulated in disease. Brenner is active in translating NR technologies to treat and prevent human conditions that disturb the NAD system including cancer diabetic and chemotherapeutic peripheral neuropathy, heart failure, central brain injury, inflammation, mitochondrial myopathy pellagra, and infections such as coronavirus infection Brenner's work included the first human trial of NR in 2016, which demonstrated safe oral availability as an NAD+ precursor, thereby creating the foundational intellectual property for the NAD boosting industry. Though Brenner was the first to show that NR increases SIR2 activity, improves gene silencing, and can extend yeast lifespan, his work has not emphasized sirtuins or nonspecific anti-aging claims and instead emphasizes how NR repairs inflammatory conditions and metabolic stresses that dysregulate NAD+ and NADPH.
Somalia is a semi-arid country with about 1.6% arable land. The first local environmental organisations were Ecoterra Somalia and the Somali Ecological Society, which promoted ecological awareness and mobilised environmental programs governmentally and through grassroots efforts. From 1971 onward, a massive tree-planting campaign on a nationwide scale was introduced by the communist government to halt the advance of wind-driven sand dunes, which threatened to engulf towns, roads and farm land. By 1988, 265 hectares of a projected 336 hectares had been treated, with 39 range reserve sites and 36 forestry plantation sites established. In 1986, the Wildlife Rescue, Research and Monitoring Centre was established by Ecoterra International, with the goal of raising ecological awareness. This effort led in 1989 to a decision by the Somali government to adhere to the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which banned the trade of elephant ivory. Following the tsunami of December 2004, it was alleged that Somalia's shoreline was used to dump toxic waste. The waves after the tsunami stirred up nuclear and toxic waste that was possibly dumped illegally by foreign firms.
== Non-traditional sales == Due to their limited restaurant locations throughout the United States, White Castle had developed a cult following among former customers who develop a craving for their hamburger in areas not served by their restaurants. By the early 1980s, these customers would go to extreme length to obtain White Castle burgers, such as having friends and relatives ship the burgers to them. In November 1980, the town officials of Fountain Hills, Arizona, placed an order for 10,000 hamburgers to be sold at a town festival as part of a fundraiser. The following year, the town created an annual festival that was held each May called Midwest Fest or Midwest Festival in which 100,000 or more hamburgers were purchased and sold as part of a fundraiser. By the middle of the decade, several other western cities were purchasing hundreds of thousands of burgers at a time for fundraisers. In 1982, a Dayton disc jockey sent 3,000 burgers to 1,200 U.S. Marines stationed in Beirut. In late 1982, White Castle established a toll free phone line in which customers can order as few as 50 burgers to be shipped frozen to any metropolitan area in the United States serviced by Federal Express for as low as $57 as part of a program called "Hamburgers to Fly". By early 1983, White Castle was shipping 10,000 hamburgers per week via FedEx. Based on the success of the sale of hamburgers shipped via air express, White Castle decided to expand their frozen hamburgers distribution by selling the burgers through supermarkets.
The main preparation of the drug commercially available is mixed with cyclizine (Diconal, Wellconal) which has the advantage of reducing nausea, vomiting and histamine release associated with strong opioid therapy. Dipipanone was also available as an oral mixture 10 mg/5 mL without the cyclizine during the 1970s–1980s in the United Kingdom. This form was rare and used normally only in drug trials and in specialist Diconal addiction clinics. Dipipanone is now the only alternative opioid left to use in the UK that is of equal strength to morphine that can be prescribed instead, aside from oxycodone and hydromorphone which are typically the second and third-line alternative to pain relief when morphine is indicated but not tolerated. A fentanyl patch may also be used, especially in cases of renal impairment. One of the limitations of using dipipanone is that it is only produced in one dosage form that is mixed with the anti-emetic and anti-histamine cyclizine at a ratio of 25% dipipanone to 75% cyclizine which limits the dose of dipipanone to an absolute maximum of 3 tablets per dose up to 4–6 times a day. This is a 10 mg dipipanone and 30 mg cyclizine formulation. It is made by the following manufacturers:
Sources: en.wikipedia.org
=== Under development === Nivasorexant (ACT-539313) – selective OX1 antagonist – under development for binge eating disorder and previously for anxiety disorders, up to phase 2 – half-life 3–7 hours Seltorexant (MIN-202, JNJ-42847922, JNJ-922) – selective OX2 antagonist – under development for major depressive disorder, insomnia, and sleep apnea, up to phase 3 – half-life 2–3 hours Tebideutorexant (JNJ-61393215, JNJ-3215) – selective OX1 antagonist – under development for major depressive disorder, no development reported for anxiety disorders and panic disorder, up to phase 2 – half-life 14–25 hours
Acute toxicity has been reportedly associated with hyperhidrosis, panic attacks, severe anxiety, mydriasis, paranoia, aggressive behavior, psychosis, rhabdomyolysis, and punding. The violent and aggressive behavior associated with acute stimulant toxicity may partially be driven by paranoia. Most drugs classified as stimulants are sympathomimetic, meaning that they stimulate the sympathetic branch of the autonomic nervous system. This stimulation leads to effects such as mydriasis (dilation of the pupils), increased heart rate, blood pressure, respiratory rate and body temperature. When these changes become pathological, they are called arrhythmia, hypertension, and hyperthermia, and may lead to rhabdomyolysis, stroke, cardiac arrest, or seizures. However, given the complexity of the mechanisms that underlie these potentially fatal outcomes of acute stimulant toxicity, it is impossible to determine what dose may be lethal.
1949), right wing conservative cultural critic; contributing editor to City Journal, published by Manhattan Institute, where he is the Dietrich Weismann Fellow; his work has appeared in The British Medical Journal, The Times, New Statesman, The Observer, The Daily Telegraph, The Spectator, The Salisbury Review, National Review, New English Review, The Wall Street Journal and Axess magasin; author of Life at the Bottom: The Worldview That Makes the Underclass, Our Culture, What's Left of It and Spoilt Rotten: The Toxic Cult of Sentimentality; his writing argues that leftist views prevalent within Western intellectual circles minimise responsibility of individuals for their own actions and undermine traditional mores, contributing to the formation within prosperous countries of an underclass afflicted by endemic violence, criminality, sexually transmitted diseases, welfare dependency, and drug abuse. Dalrymple was awarded Prize for Liberty by the Flemish classical-liberal think-tank Libera!. John Diamond, journalist Alf Dubs, Baron Dubs (b.
Chemical burns can be caused by over 25,000 substances, most of which are either a strong base (55%) or a strong acid (26%). Most chemical burn deaths are secondary to ingestion. Common agents include: sulfuric acid as found in toilet cleaners, sodium hypochlorite as found in bleach, and halogenated hydrocarbons as found in paint remover, among others. Hydrofluoric acid can cause particularly deep burns that may not become symptomatic until some time after exposure. Formic acid may cause the breakdown of significant numbers of red blood cells.
Sources: en.wikipedia.org
=== Interests === Freeman resides in Charleston, Mississippi, and maintains a home in New York City. He earned a private pilot's license at the age of 65 and owns—or has owned—at least three private aircraft, including both a Cessna Citation 501 and Cessna 414 as well as an Emivest SJ30. In December 2010, Freeman joined former President Bill Clinton, president of the United States Soccer Federation Sunil Gulati, and soccer player Landon Donovan in Zurich for a presentation to bid for the U.S. hosting rights for the 2022 FIFA World Cup. Freeman's favorite film that he did not work on is Moulin Rouge!. He later reaffirmed this during his tribute speech at Nicole Kidman's AFI Life Achievement Award ceremony.
John K. Smith opened his first pharmacy in Philadelphia in 1830. In 1865, Mahlon Kline joined the business, which 10 years later became Smith, Kline & Co. In 1891, it merged with French, Richard and Company, and in 1929, changed its name to Smith Kline & French Laboratories as it focused more on research. Years later it bought Norden Laboratories, a business doing research into animal health, and Recherche et Industrie Thérapeutiques in Belgium in 1963, to focus on vaccines. The company began to expand globally, buying seven laboratories in Canada and the United States in 1969. In 1982, it bought Allergan, a manufacturer of eye and skincare products. Smith Kline & French merged with Beckman Inc. in 1982, and changed its name to SmithKline Beckman. In 1988, it bought International Clinical Laboratories.
== Biosynthesis == The production of bottromycin by S. bottropensis and S. scabies, as well as the production of a bottromycin analog termed bottromycin D, has been studied. It was independently confirmed in 2012 by multiple groups that bottromycin is produced as a ribosomal peptide natural product that it subsequently post-translationally modified. Before this, it was unclear whether bottromycin was produced by nonribosomal peptide synthetase machinery (NRPS). The presence of amino acids other than the 20 proteinogenic amino acids is often a feature of NRPS products because NRPS machinery can directly incorporate other amino acids, among other chemical building blocks. Ribosomal peptide synthesis, which is the same machinery that produces all proteins found in the cell, is limited to the 20 proteinogenic amino acids. However, bottromycin was found to be a highly modified ribosomal peptide by a combination of genome mining and gene deletion studies. In ribosomal peptide synthesis, the final product results from modifications to a linear peptide starting material translated by the ribosome from an mRNA transcript. In S. scabies the precursor peptide, termed BtmD, is a 44-amino acid peptide. The precursor peptide is termed BmbC in S. bottropensis. The amino acids forming the bottromycin core are residues 2-9 in BtmD: Gly-Pro-Val-Val-Val-Phe-Asp-Cys. In bottromycin D, the sequence is Gly-Pro-Ala-Val-Val-Phe-Asp-Cys, and the precursor peptide is termed BstA. BstA shares high sequence homology with BtmD in the follower peptide region.
Sources: en.wikipedia.org
Usually not, though usage overlaps. The label most often refers to a short acetylated fragment of the parent protein, while thymosin beta-4 itself is the full 43-residue molecule. Because suppliers vary, a sequence statement is needed to settle the question for any particular lot.
The name is a commercial label rather than a systematic chemical designation, so different vendors and papers attach it to different sequences. Some treat it as a fragment and others as the whole protein. Comparing two reports therefore requires checking what each one actually analyzed.
Typically it reflects the relative area of the main peak in a reversed-phase chromatogram at a given wavelength. It does not confirm the amino acid sequence, the counter-ion, or the amount of peptide by mass. Identity is normally established by a separate mass measurement.
Sealed, dry and protected from light at reduced temperature is the usual laboratory convention. Allowing a cold vial to reach room temperature before opening limits condensation. Repeated opening exposes the powder to moisture and should be minimised.