This is a working overview of actin binding, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-01-02. Anything still debated is marked as such rather than presented as settled.
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.
Purity is normally assessed by reversed-phase HPLC, with the main peak reported as a percentage of total peak area, while identity is confirmed by mass spectrometry. Electrospray and MALDI-TOF instruments are both used, and the observed mass is compared with the value calculated from the stated sequence. Ion-exchange or size-exclusion methods appear where aggregation or charge variants are of interest. Water content, counter-ion content and residual trifluoroacetate from purification are separate variables that can shift the measured mass and should be weighed when reading a certificate of analysis.
Research peptides are typically supplied as a white to off-white lyophilised powder in a sealed vial. The dry solid is more stable than a solution and is normally kept refrigerated or frozen until use. Dissolution is usually done in water, phosphate-buffered saline or a similar aqueous medium, depending on the assay. Because the material is hygroscopic and easily contaminated, opening vials in a low-humidity environment and recording the lot number before use are standard laboratory practices.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C38H68N10O14 | Acetylated heptapeptide form |
| Monoisotopic mass | 888.5 Da | Average mass about 889 Da |
| Appearance | White to off-white solid | Usually supplied as lyophilised powder |
| Solubility class | Highly water soluble | Also dissolves in aqueous buffers |
| Common synonyms | Tbeta4 fragment, thymosin beta-4 (17-23) | Refer to the same sequence |
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.
Purity and identity are separate measurements and are often confused. Reverse-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, reports the share of total peak area belonging to the target compound. Mass spectrometry by electrospray or matrix-assisted laser desorption then checks whether the observed mass matches the expected sequence. Neither measurement alone shows that a vial holds the intended peptide. Peptide content, meaning the fraction of vial mass that is genuine peptide rather than counter-ion, water or residual acid, is reported separately and is frequently lower than the stated purity figure.
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.
The designation TB-500 circulates in laboratory and catalog contexts without a single agreed definition. Most product listings apply it to an N-terminally acetylated seven-residue fragment of thymosin beta-4, while other listings attach the same label to the full 43-residue protein. Because the term is commercial rather than systematic, two entries bearing identical names may describe different molecules. Any documentation should therefore state which sequence a given sample is claimed to contain.
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.
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.
Lyophilised peptide powders are hygroscopic, and the fragment absorbs atmospheric moisture when a vial is opened at room temperature. Weighing and aliquoting are normally done quickly in a dry environment, and stock solutions are divided into single-use portions before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and can shift the measured content of a vial. These practices are general to synthetic peptides rather than unique to this sequence, but they matter more for short chains kept for long periods.
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.
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.
Some hematomas are visible under the surface of the skin (commonly called bruises) or possibly felt as masses or lumps. Lumps may be caused by the limitation of the blood to a sac, subcutaneous or intramuscular tissue space isolated by fascial planes. This is an anatomical feature that helps prevent injuries from causing massive blood loss. In most cases a hematoma as a sac of blood eventually dissolves; however, in some cases it may continue to grow due to blood seepage or show no change. If the sac of blood does not disappear, then it may need to be surgically cleaned out or repaired. The slow process of reabsorption of hematomas can allow the broken down blood cells and hemoglobin pigment to move in the connective tissue. For example, an injury to the base of the thumb might cause a hematoma that moves slowly throughout the finger over the course of a week. Gravity is the main determinant of this process. Hematomas on articulations can reduce mobility of a member and present roughly the same symptoms as a fracture. In most cases, movement and exercise of the affected muscle is the best way to introduce the collection back into the bloodstream.
== Early life == She was born in London to Georgian mother Nino Kvinitadze, daughter of General Giorgi Kvinitadze, and Anglo-Dutch father Peter Claude Holland d'Abo, of a landed gentry family of West Wratting, Cambridgeshire. Maryam d'Abo was raised in Paris and Geneva. D’Abo was drawing from the age of eight, but by 13 she wanted to become an actress; she joined an amateur theatre company while at school in Geneva. She decided to do a foundation course at the London College of Printing at 18, but she abandoned those studies in order to go to drama school at Drama Centre London. She left after one term in order to make her film debut.
In October 2016, word leaked through social media that Arby's was about to test a venison sandwich, which Arby's confirmed, selecting 17 stores in Georgia, Michigan, Minnesota, Pennsylvania, Tennessee, and Wisconsin (all major deer hunting states) to offer it during a four-day test during those states' respective hunting seasons. Prior to the start of the promotion, USA Today published the locations of all 17 participating restaurants. Both due to curiosity and heavy demand from hunters, the sandwiches sold out in all markets on the first day of the test. Another USA Today article reported that the farm-raised venison was imported from New Zealand. In the following year, Arby's announced that the venison sandwich would return nationwide on October 21, 2017, also available in limited quantities. In September 2017, Arby's introduced the Chicken Pepperoni Parm sandwich, their version of a chicken parmigiana sandwich which also contains pepperoni slices. In October 2017, Arby's announced that three locations in Colorado, Montana, and Wyoming will offer an elk sandwich for a limited time. The farm-raised elk meat that was used to make the sandwiches was obtained from the same farm in New Zealand that provides the venison to Arby's since many states, such as Montana, prohibit the raising of game animals on commercial farms. The following October, Arby's once again offered a featured wild game sandwich in 16 of its restaurants. This time, it would be a duck breast sandwich topped with a cherry sauce and crispy onions.
The first was Nordenfelt I, a 56-tonne, 19.5-metre (64 ft) vessel similar to Garrett's ill-fated Resurgam (1879), with a range of 240 kilometres (130 nmi; 150 mi), armed with a single torpedo, in 1885.
Many affected infants also have distinctive abnormalities of the head and facial (craniofacial) area. Many of the physical features associated with the disorder are congenital. In most cases, premature closure of fibrous joints (sagittal sutures) between certain bones (parietal bones) of the skull may restrict lateral growth of the skull, causing it to appear abnormally long and narrow that is disproportionate to the body size. In addition, the forehead may be abnormally prominent and the face may be triangular shaped with a hypo plastic mid face, pointed chin. Infants with this disorder may also have abnormally flat cheeks and cheekbones, large ears, prominent mouth with widely spread lips, and or underdeveloped upper jaw bones (maxillary hypoplasia). In addition, in some cases, the teeth may be abnormally crowded together, particularly toward the front of the mouth (anterior crowding) and as a result, the upper result, the upper jaw and lower teeth may not meet properly, they might be abnormally crowded together.
Sources: en.wikipedia.org
As a final step, McMillan and Abelson prepared a much larger sample of bombarded uranium that had a prominent 23-minute half-life from 239U and demonstrated conclusively that the unknown 2.3-day half-life increased in strength in concert with a decrease in the 23-minute activity through the following reaction:
Because lithium-ion batteries can have a variety of positive and negative electrode materials, the energy density and voltage vary accordingly. The open-circuit voltage is higher than in aqueous batteries (such as lead–acid, nickel–metal hydride and nickel–cadmium). Internal resistance increases with both cycling and age, although this depends strongly on the voltage and temperature the batteries are stored at. Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw. Eventually, increasing resistance will leave the battery in a state such that it can no longer support the normal discharge currents requested of it without unacceptable voltage drop or overheating. Batteries with a lithium iron phosphate positive and graphite negative electrodes have a nominal open-circuit voltage of 3.2 V and a typical charging voltage of 3.6 V. Lithium nickel manganese cobalt (NMC) oxide positives with graphite negatives have a 3.7 V nominal voltage with a 4.2 V maximum while charging. The charging procedure is performed at constant voltage with current-limiting circuitry (i.e., charging with constant current until a voltage of 4.2 V is reached in the cell and continuing with a constant voltage applied until the current drops close to zero). Typically, the charge is terminated at 3% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less.
==== Off-line ==== Off-line storage requires some direct action to provide access to the storage media: for example, inserting a tape into a tape drive or plugging in a cable. Because the data is not accessible via any computer except during limited periods in which they are written or read back, they are largely immune to on-line backup failure modes. Access time varies depending on whether the media are on-site or off-site.
Chronic cholestasis occurs in primary biliary cholangitis (PBC). PBC is a progressive autoimmune liver disease in which small intrahepatic bile ducts are selectively destroyed, leading to cholestasis, biliary fibrosis, cirrhosis, and eventually liver failure that requires transplantation. Prevalence of PBC ranges from 19 to 402 cases/million depending on geographic location, with a 9:1 female preponderance and median ages of diagnosis of 68.5 years for females and 54.5 years for males. At diagnosis, 50% of PBC patients are asymptomatic, indicative of an early stage of disease, while another 50% report fatigue and daytime sleepiness. Other symptoms include pruritus and skin lesions, and in prolonged cholestasis, malabsorption and steatorrhea leading to fat-soluble vitamin deficiency. Disease progression is accompanied by intensifying portal hypertension and hepatosplenomegaly. Clinically, diagnosis generally requires a 1:40 or greater titer of anti-mitochondrial antibody (AMA) against PDC-E2 and elevated alkaline phosphatase persisting for 6+ months. Ursodeoxycholic acid (UDCA) is an FDA-approved first-line treatment for PBC. At moderate doses, UDCA has been demonstrated to slow disease progression and improve transplant-free survival. A complete response is achieved in 25–30% patients, and similar survival as the general population is expected in 2/3 of patients on UDCA. For the 1/3 non-responders, obeticholic acid (OCA) is approved by the FDA as a second-line treatment. The precise etiology of PBC remains poorly understood, though a clearer picture is starting to emerge.
=== Neurological === Higher concentrations of TGF-β are found in the blood and cerebrospinal fluid of patients with Alzheimer's disease as compared to control subjects, suggesting a possible role in the neurodegenerative cascade leading to Alzheimer's disease symptoms and pathology. The role of TGF-β in neuronal dysfunction remains an active area of research.
Sources: en.wikipedia.org
=== Soft tissue rheumatism === Local diseases and lesions affecting the joints and structures around the joints including tendons, ligaments capsules, bursae, stress fractures, muscles, nerve entrapment, vascular lesions, and ganglia. For example:
== Synthesis == HMX is more complicated to manufacture than most explosives, and this confines it to specialist applications. It and RDX are both produced by the Bachmann process—nitration of hexamine using a mixture of ammonium nitrate and nitric acid in a mixture of acetic acid and acetic anhydride as solvent—with the major product determined by the specific reaction conditions.
Especially since 2023, Xi has also overseen significant anti-corruption efforts in the military, with some targets involving those that rose to prominence under his leadership. Those targeted included former defense ministers Li Shangfu and Wei Fenghe, CMC vice chairmen He Weidong and Zhang Youxia, and CMC member Miao Hua. In addition, former Xinjiang Party Secretary and Politburo member Ma Xingrui was put under investigation in 2026. Bloomberg News estimated that as October 2025, at least 14 generals out of 79 appointed under Xi's leadership have been ousted. Xi has introduced stringent restrictions on naked officials, CCP officials with spouses or children residing abroad, eventually culminating in a 2025 campaign to require cadres of vice-ministerial rank or above being required to either repatriate family members or resign from office.
The known amino acids to be targeted in the protein are tyrosine and threonine, and sometimes serine. When charges on a protein undergo a change, it affects the characteristics of the protein, normally by altering its shape via interactions of the amino acids which make up the protein. AMPylation can have various effects on the protein. These are properties of the protein like, stability, enzymatic activity, co-factor binding, and many other functional capabilities of a protein. Another function of adenylylation is amino acids activation, which is catalyzed by tRNA aminoacyl synthetase. The most commonly identified protein to receive AMPylation are GTPases, and glutamine synthetase.
==== Adverse effects ==== The most common adverse effects of nabilone include drowsiness, dizziness, dry mouth, euphoria, concentration difficulties, ataxia, and headache. It has the potential to affect the central nervous system, resulting in anxiety, disorientation, depression, hallucinations and psychosis. Moreover, it may lead to cardiovascular side effects such as orthostatic hypotension and tachycardia. Gastrointestinal adverse reactions also include anorexia, constipation, nausea, vomiting, and oral paresthesia (sensation of tingling in the mouth).
Sources: en.wikipedia.org
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.
It consists of leucine, lysine, lysine, threonine, glutamic acid, threonine, and glutamine in that order. The N-terminal leucine is usually acetylated in the forms described in catalogues.
Controlled human data is limited, and most published findings come from cell culture or animal work. This makes it difficult to state clinical effects with confidence.
Sealed, desiccated and protected from light, at -20 °C or lower for long-term storage. Short-term storage at refrigerator temperature is common in working laboratories.