If you have been reading about actin binding and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-07-24. Numbers and descriptions here follow the published literature rather than marketing material.
Animal work has examined the peptide in models of cardiac injury, skin wounding, and corneal repair, with reported outcomes covering cell migration, inflammatory cell influx, and tissue remodeling. Several of those experiments used the full-length protein or longer fragments instead of the seven-residue sequence, which makes direct comparison between reports difficult. Results are generally described as tissue-dependent, and effect sizes vary considerably across laboratories. Independent replication is uneven, so the overall picture is incomplete rather than settled.
Controlled human trials of the short fragment are scarce. Much of what appears in review articles is extrapolated from animal models or from studies of the parent protein, and literature searches return a larger body of cardiac and ophthalmic work on thymosin beta-4 than on the abbreviated peptide. Regulatory treatment differs by jurisdiction, and in several countries the material is handled as a research chemical rather than an approved therapeutic. Statements about human benefit should be read as provisional.
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.
Once dissolved, the peptide is far less stable than the dry powder. Aqueous solutions are subject to hydrolysis, oxidation at susceptible residues and gradual loss of material through adsorption onto glass and plastic surfaces. Terminal glutamine can cyclise under some conditions, producing a related species that complicates purity assessment. Dilute solutions tend to lose a larger fraction of material to surfaces than concentrated ones. Buffers, pH and ionic strength all influence the rate of change, so stability figures are only meaningful when those parameters are stated alongside the storage interval.
| Property | Value | Notes |
|---|---|---|
| Common synonyms | Thymosin beta-4 fragment; TB4 fragment | Naming is inconsistent across suppliers and publications |
| Reported sequence | Ac-LKKTETQ | Corresponds to residues 17-23 of the parent protein |
| Frequently cited registry number | 77591-33-4 | Associated with full-length thymosin beta-4 rather than the fragment |
| Common supplied form | Freeze-dried solid | Often presented as an acetate or trifluoroacetate salt |
| Regulatory treatment | Varies by country | Frequently handled as a research chemical; not broadly approved as a therapeutic |
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.
TB-500 is a research peptide whose sequence matches residues 17 to 23 of thymosin beta-4, a 43-residue protein present in most mammalian cells. The chain is seven amino acids long, written as LKKTETQ, and is normally supplied with an acetyl group on the N-terminus. Suppliers list it as a lyophilised powder under the code name TB-500, and the same sequence appears elsewhere in catalogues as the thymosin beta-4 actin-binding fragment. The label is commercial rather than systematic, so no single authority fixes exactly what TB-500 denotes.
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.
=== Concentrating protein solutions === After initial purification, protein solutions may need to be concentrated to increase the protein's concentration for downstream applications. This can be achieved through various methods, including ultrafiltration, which uses semi-permeable membranes to separate proteins from smaller molecules and salts, and lyophilization (freeze-drying), which removes water and allows proteins to be stored in a stable form. Precipitation methods, such as ammonium sulfate precipitation, can also be employed to concentrate proteins by altering the solubility conditions.
The close of the Cretaceous period saw the demise of the Mesozoic era reptilian megafauna (see the Cretaceous–Paleogene extinction event, also known as K-T extinction event). Of the large marine reptiles, only sea turtles were left; and of the non-marine large reptiles, only the semi-aquatic crocodilians and broadly similar choristoderes survived the extinction, with last members of the latter, the lizard-like Lazarussuchus, becoming extinct in the Miocene. Of the great host of dinosaurs dominating the Mesozoic, only the small beaked birds survived. This dramatic extinction pattern at the end of the Mesozoic led into the Cenozoic. Mammals and birds filled the empty niches left behind by the reptilian megafauna and, while reptile diversification slowed, bird and mammal diversification took an exponential turn. However, reptiles were still important components of the megafauna, particularly in the form of large and giant tortoises. After the extinction of most archosaur and marine reptile lines by the end of the Cretaceous, reptile diversification continued throughout the Cenozoic. Squamates took a massive hit during the K–Pg event, only recovering ten million years after it, but they underwent a great radiation event once they recovered, and today squamates make up the majority of living reptiles (> 95%). Approximately 10,000 extant species of traditional reptiles are known, with birds adding about 10,000 more, almost twice the number of mammals, represented by about 5,700 living species (excluding domesticated species).
On 8 December 2023, authorities reportedly denied her transfer request from the Rampton Secure Hospital, a high-security psychiatric facility, to a mainstream prison. She will not be eligible for another assessment until 2026 at the earliest.
Copper IUDs acts as a spermicide. Copper ions released from the IUD damage sperm and disrupt their ability to move, preventing sperm from traveling through the cervical mucus or destroying them as they pass through so that they never meet the egg. They also start a local inflammatory reaction that causes the uterus and fallopian tubes to produce a fluid that contains white blood cells, enzymes, and prostaglandins, which are toxic to sperm. While not the main mechanism of action, studies have found that copper can also alter the endometrial (uterine) lining. This alteration can prevent implantation of a fertilized egg ("blastocyst"), but it cannot disrupt a fertilized egg that has already been implanted in the uterine lining.
In the establishment of the Soviet Union in the former Russian Empire, Bolshevism was the ideological basis. As the only legal vanguard party, it decided almost all policies, which the communist party represented as correct. Because Leninism was the revolutionary means to achieving socialism in the praxis of government, the relationship between ideology and decision-making inclined to pragmatism and most policy decisions were taken in light of the continual and permanent development of Marxism–Leninism, with ideological adaptation to material conditions. The Bolshevik Party lost in the 1917 Russian Constituent Assembly election, obtaining 23.3% of the vote, to the Socialist Revolutionary Party, which obtained 37.6%. On 6 January 1918, the Draft Decree on the Dissolution of the Constituent Assembly was issued by the Central Executive Committee of the Congress of Soviets, a committee dominated by Vladimir Lenin, who had previously supported multi-party free elections. After the Bolshevik defeat, Lenin started referring to the assembly as a "deceptive form of bourgeois-democratic parliamentarism". This was criticised as being the development of vanguardism as a form of hierarchical party–elite that controlled society. Within five years of the death of Lenin, Joseph Stalin completed his rise to power and was the leader of the Soviet Union who theorised and applied the socialist theories of Lenin and Karl Marx as political expediencies used to realise his plans for the Soviet Union and for world socialism.
Sources: en.wikipedia.org
== Isoform diversity == Amyloid-beta precursor protein is highly versatile with several isoforms generated through alternative splicing of its mRNA. The primary isoforms include APP695, APP751, and APP770, differing in their inclusion of certain exons, mainly exon 7 and 8. APP695 is predominantly expressed in neuronal cells and is crucial for normal neuronal function. APP751 and APP770 are more widely expressed in non-neuronal tissues but exhibit distinct expression patterns during neuron differentiation. The differential expression of these isoforms plays a significant role in cellular processes such as neurodevelopment, synaptic plasticity, and the pathogenesis of Alzheimer's disease. Understanding the isoform diversity of APP is essential for deciphering its various physiological and pathological roles.
Rachel Jane Nickell (23 November 1968 – 15 July 1992) was a British woman who was stabbed to death on Wimbledon Common in southwest London on 15 July 1992. The initial police investigation of the crime resulted in the arrest in controversial circumstances of an innocent man, who was acquitted. Nickell was walking with her two-year-old son on Wimbledon Common when she was stabbed 49 times in the neck and torso and died at the scene. A lengthy police investigation to find the perpetrator followed, during which a suspect was wrongfully charged and later acquitted—before the case went cold. The detectives involved in arresting the innocent man had rejected, with "hostility", a suggestion from detectives investigating the November 1993 murders of single mother Samantha Bisset and her four-year-old daughter, Jazmine, as having been perpetrated by the same suspect due to a preponderance of similarities in the crimes. In 2006, a cold case investigation did identify Robert Napper – the man caught and convicted in 1995 for the Bisset murders – as Nickell's murderer. In 2008, Napper pleaded guilty to Nickell's manslaughter on the grounds of diminished responsibility. Napper, who was already detained at high-security Broadmoor Hospital in Berkshire for the Bisset murders, was ordered to be detained there indefinitely.
The plasma pH can be altered by respiratory changes in the partial pressure of carbon dioxide; or altered by metabolic changes in the carbonic acid to bicarbonate ion ratio. The bicarbonate buffer system regulates the ratio of carbonic acid to bicarbonate to be equal to 1:20, at which ratio the blood pH is 7.4 (as explained in the Henderson–Hasselbalch equation). A change in the plasma pH gives an acid–base imbalance. In acid–base homeostasis there are two mechanisms that can help regulate the pH. Respiratory compensation a mechanism of the respiratory center, adjusts the partial pressure of carbon dioxide by changing the rate and depth of breathing, to bring the pH back to normal. The partial pressure of carbon dioxide also determines the concentration of carbonic acid, and the bicarbonate buffer system can also come into play. Renal compensation can help the bicarbonate buffer system. The sensor for the plasma bicarbonate concentration is not known for certain. It is very probable that the renal tubular cells of the distal convoluted tubules are themselves sensitive to the pH of the plasma. The metabolism of these cells produces carbon dioxide, which is rapidly converted to hydrogen and bicarbonate through the action of carbonic anhydrase. When the ECF pH falls (becoming more acidic) the renal tubular cells excrete hydrogen ions into the tubular fluid to leave the body via urine. Bicarbonate ions are simultaneously secreted into the blood that decrease the carbonic acid, and consequently raise the plasma pH.
In late August 2013, Starbucks announced its first store in Colombia at a press conference in Bogotá, where the company's CEO explained, "Starbucks has always admired and respected Colombia's distinguished coffee tradition." In May 2014, Starbucks announced its first café in Bolivia would open in 2014 in Santa Cruz de la Sierra and the first in Panama in 2015. In January 2016, Starbucks announced that it would launch operation in Trinidad and Tobago. On August 29, 2016, Starbucks opened its first store at South Park Mall in San Fernando. In November 2017, Starbucks commenced operations in Jamaica, where the first store opened in the resort city of Montego Bay on the shores of the Doctor's Cave Beach Club, offering views of the Caribbean Sea. The company also reaffirmed its commitment to working with local coffee farmers to "implement systems to increase productivity and yields, while also increasing compliance to international standards". Starbucks Jamaica opened its first store on November 21, 2017, with plans to open 15 locations island-wide over a 5-year period. Starbucks Jamaica opened stores at the Sangster International Airport in Montego Bay and at the Falmouth Pier, in Falmouth, Jamaica. Starbucks Jamaica announced plans to open up to six stores in Kingston, Jamaica, by 2019. The first of the Kingston stores opened on June 21, 2018. The second store is in Kingston's central business district, New Kingston.
Signs and Symptoms Rough, red rash Lymphadenopathy Abnormal thickening of the palms of the hands and soles of the feet Hair loss of balding Nail trauma Ectropion Liver and Spleen become swollen 4 Stages (link) Diagnosis Physical exam to check for lesions Peripheral blood smear Use a microscope to count the number of blood cells and look at their shape. Skin biopsy Checks for signs of cancer Immunophenotyping Flow cytometry T-cell receptor gene rearrangement test Liver Function test HIV test X-ray, CT scan, and PET scan To determine if the lymphoma is metastatic Treatments Chemotherapy Radiation Drug Therapy Photodynamic Therapy Biologic Therapy using Interferon Targeted Therapy UV Radiation Therapy Clinical Trials being pursued Stem cell transplant combined with chemoradiation Clinical trials being pursued
Sources: en.wikipedia.org
== See also == Ketoconazole, another antifungal agent used in shampoos Piroctone olamine, another antifungal agent used in shampoos Selenium disulfide, an active ingredient used in shampoos such as Selsun Blue
== Dietary supplement == Although neither a prescription drug nor an essential nutrient, CoQ10 is commonly used as a dietary supplement with the intent to prevent or improve disease conditions, such as cardiovascular disorders. Despite its significant role in the body, it is not used as a drug to treat any specific disease. Nevertheless, CoQ10 is widely available as an over-the-counter dietary supplement and is recommended by some healthcare professionals, despite a lack of definitive scientific evidence supporting these recommendations, especially when it comes to cardiovascular diseases.
Playing Cards (French: Une partie de cartes, literally "A Card Party") is an 1896 French black-and-white silent actuality film by Georges Méliès. It was the first film in Méliès' prolific career, and thus is number one in his Star Film catalogue. It is a remake of Louis Lumière's film The Messers. Lumière at Cards, which was released earlier the same year. Along with Georges Méliès himself, his brother Gaston Méliès and daughter Georgette Méliès also appear in the film.
=== Antifungal properties === Capsaicin acts as an antifungal agent in four primary ways. First, capsaicin inhibits the metabolic rate of the cells that make up the fungal biofilm. This inhibits the area and growth rate of the fungus, since the biofilm creates an area where a fungus can grow and adhere to the chili in which capsaicin is present. Capsaicin also inhibits fungal hyphae formation, which impacts the amount of nutrients that the rest of the fungal body can receive. Thirdly, capsaicin disrupts the structure of fungal cells and the fungal cell membranes. This has consequential negative impacts on the integrity of fungal cells and their ability to survive and proliferate. Additionally, the ergosterol synthesis of growing fungi decreases in relation to the amount of capsaicin present in the growth area. This impacts the fungal cell membrane, and how it is able to reproduce and adapt to stressors in its environment.
To reduce the effects of the testosterone flare at the initiation of GnRH agonist therapy in men Androgen-dependent skin and hair conditions such as acne, seborrhea, excessive hair growth, and scalp hair loss in women as well as high testosterone levels due to polycystic ovary syndrome (PCOS) in women, at 25 to 50 mg/day generally in combination with a birth control pill Feminizing hormone therapy for transgender women usually at 50 mg/day in combination with an estrogen. Peripheral precocious puberty in boys at 12.5 to 100 mg/day in combination with an aromatase inhibitor like anastrozole, especially for familial male-limited precocious puberty (testotoxicosis) Overly long-lasting erections in men at 50 mg per week to 50 mg every other day The medication has been suggested for but has uncertain effectiveness in the following indication:
Sources: en.wikipedia.org
The leading proposal involves sequestration of monomeric actin, which would alter cytoskeletal turnover and cell movement. The actin-binding motif shared with the parent protein is central to that idea. Direct confirmation in whole organisms remains limited.
Very few controlled human studies focus on the seven-residue sequence itself. Most clinical data concern the full-length protein in cardiac or ophthalmic settings. Conclusions drawn for one form should not be assumed to transfer to the other.
Detection normally relies on reversed-phase liquid chromatography paired with mass spectrometry. Chromatographic retention time establishes the expected elution window, and the mass spectrum confirms the molecular ion. Immunoassays exist but can cross-react with related peptides.
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.