Everything below concerns peptide fragment. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-02-07. Numbers and descriptions here follow the published literature rather than marketing material.
TB-500 is a synthetic heptapeptide with the sequence Ac-LKKTETQ. It corresponds to a short N-terminal region of thymosin beta-4, a 43-amino-acid protein found in many cell types. The fragment contains an actin-binding motif, which is one reason it appears in laboratory studies of cell migration and cytoskeletal dynamics. TB-500 is not the full-length protein and is produced as a research chemical rather than an approved therapeutic agent. Its molecular weight is approximately 889 Da.
Several names appear in scientific and commercial contexts for this peptide. The label TB-500 is informal and does not follow standard biochemical nomenclature. Research articles more often describe the compound as a thymosin beta-4 fragment, Tβ4 fragment, or by its sequence Ac-LKKTETQ. Confusing TB-500 with full-length thymosin beta-4 can lead to incorrect assumptions about activity because the fragment lacks the remaining residues of the parent protein. The relationship between fragment and parent protein remains an active area of study.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H68N10O14 | Calculated for the acetylated heptapeptide |
| Molecular weight | ~889 Da | Monoisotopic mass approximately 889.0 Da |
| Amino acid sequence | Ac-LKKTETQ | N-terminal acetylated seven-residue peptide |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Water-soluble | Peptides of this size generally dissolve in aqueous media |
Interest in the compound comes largely from studies of the parent protein, which participates in actin sequestration, cell migration and tissue repair processes. Whether a short fragment reproduces those activities is a separate question that remains open in the published record. Many summaries describe mechanisms by analogy to thymosin beta-4 rather than from direct measurements on the fragment. Claims about activity should be treated as provisional unless a cited study specifies the exact peptide, its purity and the assay used.
TB-500 is a laboratory label applied to a short synthetic peptide that is widely described as a fragment of thymosin beta-4, an actin-binding protein present in most mammalian cells. Suppliers and review articles usually present TB-500 as the N-terminal region of that protein, but the exact sequence attached to the name is not consistent across sources. Some product descriptions list a seven-residue chain; others use the label loosely for the parent protein itself. Because of that variation, any technical discussion of TB-500 needs to state which sequence is meant.
Thymosin beta-4 contains 43 amino acids and has a reported molecular mass near 4963 Da. The short fragment most often associated with the TB-500 label, an acetylated chain beginning LKKTETQ, has a reported mass near 889 Da, so the two are easily separated in analytical work. Mass spectrometry and amino acid analysis can confirm which material is present in a given sample. Statements treating TB-500 and thymosin beta-4 as interchangeable are therefore imprecise, even though the two appear together in much of the same literature.
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.
The regulatory position is broadly consistent across major jurisdictions: no thymosin beta-4 fragment is an approved medicine, and laboratory material is commonly labelled as not intended for human consumption. Anti-doping rules in sport list thymosin beta-4 and its fragments among prohibited peptide hormones. Because these products travel through research-chemical channels rather than pharmaceutical supply chains, quality varies considerably between vendors. Independent testing of identity, purity and sterility is the only dependable check, and a certificate of analysis describes one batch rather than a supplier's whole catalogue.
Lyophilized peptide powder is normally held desiccated at −20 °C, with −80 °C used for longer storage periods. Allowing a sealed vial to reach room temperature before opening is standard practice, because condensation forming on cold powder introduces moisture. Once dissolved, solutions are typically kept cold and shielded from light. Repeated freeze-thaw cycles are avoided because they encourage aggregation and gradual loss of material. These conventions are general to synthetic peptides rather than unique to any one sequence.
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.
TB-500 is a synthetic seven-amino-acid peptide with the sequence LKKTETQ, corresponding to residues 17 through 23 of the protein thymosin beta-4. The N-terminus is typically acetylated in the described form, giving a monoisotopic mass near 888.5 Da and an average mass of about 889 Da. The designation TB-500 is a catalogue label rather than a formal chemical name, and the same sequence appears in the literature under several alternative abbreviations. It is handled as a research reagent rather than a pharmaceutical product.
Most Moluccans in northern Maluku (present-day province of North Maluku) are Muslim. Central and southern Maluku (present-day province of Maluku) have approximately equal numbers of Muslims and Christians. There is significant number of native Hindus (Tanimbar Kei people) living in the Kei Islands, which is a predominantly Catholic region. This is because, according to oral traditions, their ancestors came from Bal (Bali) during the Majapahit era. Additionally, they practice local customary law called Larvul Ngabal (transl. "red blood and spear from Bali"). The most common religion amongst Moluccans in the Netherlands is Protestantism, followed by Islam.
=== Fifth Republic === December 23, 1958: Decree amending various criminal provisions to introduce a fifth class of police contraventions; notably punishes passive soliciting. December 30, 1958: The term "birth allowance" replaces "maternity allowance," and the conditions for both that and the single wage allowance are modified. February 4, 1959: Ordinance on the general status of civil servants, which includes the principle of non-discrimination based on sex, except in certain exceptional cases, notably in the national police. April 9, 1960: Decree concerning the family record book. November 25, 1960: Ordinance on the fight against pimping. November 25, 1960: By decree, passive soliciting becomes a 3rd-class offense, active soliciting a 5th-class offense. December 2, 1960: France ratifies the United Nations Convention for the Suppression of the Traffic in Persons and of the Exploitation of the Prostitution of Others; the sanitary and social registry of prostitutes — created by law on April 24, 1946, and listing about 30,000 people in 1960 — is abolished. July 13, 1965: Law reforming matrimonial regimes: modification of the legal regime for marriages without a contract: the wife is free to manage her own property and pursue professional activity, no longer needing her husband's consent. September 29, 1965: Order establishing a study and liaison committee on women's labor issues. July 11, 1966: Law reforming adoption. December 30, 1966: Law on job protection in cases of maternity.
Suckling lamb or milk-fed lamb Meat from an unweaned lamb, typically 4–6 weeks old and weighing 5.5–8 kg; this is typically unavailable in the United States and the United Kingdom. The flavour and texture of milk-fed lamb when grilled (such as the small lamb cutlets known as chuletillas in Spain) or roasted (lechazo asado or cordero lechal asado) is generally thought to be finer than that of older lamb, and fetches higher prices. The areas in northern Spain where this can be found include Asturias, Cantabria, Castile and León, and La Rioja. Milk-fed lambs are especially prized for Easter in Greece, when they are roasted on a spit. Young lamb A milk-fed lamb between six and eight weeks old Spring lamb A lamb, usually three to five months old, born in late winter or early spring and sold usually before 1 July (in the northern hemisphere). Sucker lambs A term used in Australia — includes young milk-fed lambs, as well as slightly older lambs up to about seven months of age which are also still dependent on their mothers for milk. Carcasses from these lambs usually weigh between 14 and 30 kg. Older weaned lambs which have not yet matured to become mutton are known as old-season lambs.
Muscular dystrophy is a group of disorders associated with progressive muscle weakness and loss of muscle mass. These disorders are caused by genetic mutations. The disease affects between 19.8 and 25.1 per 100,000 person-years globally. There are more than 30 types of muscular dystrophy. Depending on the type, muscular dystrophy can affect a person's heart and lungs, and can affect the ability to move, walk, and perform daily activities. The most common types include:
Sources: en.wikipedia.org
== Biography == Richardson was born on January 25, 1941, and grew up in Teaneck, New Jersey. Her father was an electrical engineer and her mother was an English teacher. Her parents encouraged an interest in science and she was a member of local astronomy clubs as early as elementary school. She attended Teaneck High School and in 1958 won third place in the Westinghouse Science Talent Search, the most prestigious science fair in the United States, with calculations of the satellite Sputnik's orbit from her own observations. She continued her education intending to study mathematics, astronomy and physics at Swarthmore College. However, Richardson instead graduated Phi Beta Kappa with a bachelor's degree in philosophy and a minor in physics in 1962 before she pursued graduate work in philosophy at Harvard University. Meanwhile, she was able to enroll in plant taxonomy and evolution courses at Harvard that would later contribute to her big-picture approach to studying protein structure. Since Harvard's philosophy focused on modern philosophy instead of Richardson's interest, classical philosophy, Richardson left with her master's degree from Harvard in 1966. Post-graduation, Richardson tried teaching high school, but soon realized that this career path was not for her. She subsequently rejoined the scientific world, working as a technician at Massachusetts Institute of Technology in the same laboratory as her husband, David Richardson, whom she met at Swarthmore College.
Optical: To improve visual acuity by replacing the opaque or distorted host tissue by clear healthy donor tissue. The most common indication in this category is pseudophakic bullous keratopathy, followed by keratoconus, corneal degeneration, keratoglobus and dystrophy, as well as scarring due to keratitis and trauma. Tectonic/reconstructive: To preserve corneal anatomy and integrity in patients with stromal thinning and descemetoceles, or to reconstruct the anatomy of the eye, e.g. after corneal perforation. Therapeutic: To remove inflamed corneal tissue unresponsive to treatment by antibiotics or anti-virals. Cosmetic: To improve the appearance of patients with corneal scars that have given a whitish or opaque hue to the cornea.
National teams April 29 – May 1: 2018 FIBA 3x3 Asia Cup in Shenzhen Men: Australia defeated Mongolia, 17–16, in the final. Japan took third place. Women: New Zealand defeated China, 14–11, in the final. Australia took third place. August 5 – 11: 2018 FIBA Under-18 Asian Championship in Thailand In the final, Australia defeated New Zealand, 73–62, to win their 1st title. China took third place. Note: All teams mentioned here, plus Philippines, have qualified to compete at the 2019 FIBA Under-19 Basketball World Cup. October 28 – November 3: 2018 FIBA Under-18 Women's Asian Championship in Bangalore China defeated Japan, 89–76, to win their fifth consecutive and 16th overall FIBA Under-18 Women's Asian Championship title. Australia took third place. Note: All teams mentioned here, plus South Korea, have qualified to compete at the 2019 FIBA Under-19 Women's Basketball World Cup. Clubs teams November 17, 2017 – May 2: 2017–18 ABL season San Miguel Alab Pilipinas defeated Mono Vampire, 3–2 in games played in a 5-legged final, to win their first ABL title. July 17 – 22: Summer Super 8 in Macau Guangzhou Long-Lions defeated Seoul Samsung Thunders, 78–72, to win their first title. Incheon Electroland Elephants took third place.
=== Trim weights in aircraft === Aircraft that contain depleted uranium trim weights for stabilizing wings and control surfaces (such as the Boeing 747–100) may contain between 652 and 1,059 pounds (296 and 480 kg) of DU. This application is controversial because the DU might enter the environment if the aircraft crashes. The metal can also oxidize to a fine powder in a fire. Its use has been phased out in many newer aircraft. Boeing and McDonnell-Douglas discontinued using DU counterweights in the 1980s. Depleted uranium was released during the crash of El Al Flight 1862 on 4 October 1992, in which 152 kilograms (335 lb) was lost, but a case study concluded that there was no evidence to link depleted uranium from the plane to any health problems. DU counterweights manufactured with cadmium plating are considered non-hazardous as long as the plating is intact.
Inhibitors of dipeptidyl peptidase 4 (DPP-4 inhibitors or gliptins) are a class of oral hypoglycemics that block the enzyme dipeptidyl peptidase-4 (DPP-4). They can be used to treat diabetes mellitus type 2. The first agent of the class—sitagliptin—was approved for marketing by the US Food and Drug Administration (FDA) in 2006. Glucagon increases blood glucose levels, and DPP-4 inhibitors reduce glucagon and blood glucose levels. The mechanism of DPP-4 inhibitors is to increase incretin levels (GLP-1 and GIP), which inhibit glucagon release, which in turn increases insulin secretion, decreases gastric emptying, and decreases blood glucose levels. A 2018 meta-analysis found no favorable effect of DPP-4 inhibitors on all-cause mortality, cardiovascular mortality, myocardial infarction or stroke in patients with type 2 diabetes.
Sources: en.wikipedia.org
Bromelain extract is a mixture of protein-digesting (proteolytic) enzymes and several other substances in smaller quantities. The proteolytic enzymes are sulfhydryl proteases; a free sulfhydryl group of a cysteine amino acid side chain is required for function. The two main enzymes are:
===== Doctor of Pharmacy (PharmD) ===== The Doctor of Pharmacy Degree is the only entry-level professional degree offered by the college. The program is fully accredited by the Accreditation Council for Pharmacy Education. Graduates are eligible to sit for the North American Pharmacist Licensure Examination (NAPLEX). Approximately 97 students are enrolled into each class. The Doctor of Pharmacy curriculum is divided into the following:
Aspartame (N-L-α-aspartyl-L-phenylalanine 1-methyl ester) is an artificial sweetener. Carnosine (beta-alanyl-L-histidine) and Anserine (beta-alanyl-N-methyl histidine) are highly concentrated in muscle and brain tissues. They are used in sports medicines. Acetylcarnosine, cataract prevention Ala-Gln and Gly-Tyr, infusion Val-Tyr, antihypertensive
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Sources: en.wikipedia.org
TB-500 is a synthetic heptapeptide corresponding to a fragment of thymosin beta-4. It is used in laboratory research and is not an approved drug.
No. Thymosin beta-4 is a 43-amino-acid protein, while TB-500 represents only a short N-terminal segment. The two should not be treated as interchangeable in experimental design.
It is often called a thymosin beta-4 fragment, Tβ4 fragment, or Ac-LKKTETQ. The name TB-500 is mainly a commercial or catalog label rather than a formal chemical name.
Dry lyophilized powder is usually kept frozen, desiccated, and out of direct light. Sealed vials are not opened until needed, because moisture uptake can degrade short peptides. Longer archival storage is often done at lower temperatures than routine working stock.