If you have been reading about prothymosin alpha 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.
Last reviewed on 2025-10-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
The peptide was described in the 1970s as a component of thymic extracts, and early research focused on restoring immune function in immunodeficiency states. A synthetic version entered clinical development in the 1980s and is approved as a drug in several countries for conditions such as chronic hepatitis B and certain immunodeficiencies. Approval status varies widely by jurisdiction, and in the United States it is not an approved therapeutic. Regulatory and clinical positions differ, so statements about efficacy should be tied to specific indications and studies.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids, corresponding to the N-terminal fragment of prothymosin alpha. Its sequence begins with acetylation at the N-terminus, a modification that affects stability and receptor interaction. The peptide is acidic, with a calculated isoelectric point near 4.2, and carries no disulfide bonds, so its secondary structure is largely flexible in solution. Molecular mass is approximately 3108 daltons. The native form was first isolated from bovine thymus tissue, while pharmaceutical material is produced by solid-phase peptide synthesis.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The molecule consists of 28 amino acid residues with an acetyl group attached to the N-terminal serine. Its sequence is acidic overall, with several glutamic and aspartic acid residues distributed along the chain and no cysteine, so disulfide bridges do not form. The peptide carries a net negative charge at physiological pH. Because the N-terminus is blocked, the intact molecule resists degradation by many aminopeptidases, which contributes to its stability in biological fluids.
The peptide is generated in cells by cleavage of prothymosin alpha, a larger acidic protein encoded by the PTMA gene. Prothymosin alpha is expressed in many tissues, not only in the thymus, and its functions include nuclear roles in chromatin-related processes. The 28-residue fragment corresponds to the N-terminal portion of that precursor. How the cleavage occurs and how the fragment's concentration is regulated remain open questions; circulating amounts are small and difficult to measure reliably with routine assays.
==== Melzer's reagent ==== Chloral hydrate is an ingredient used to make Melzer's reagent, an aqueous solution that is used to identify certain species of fungi. The other ingredients are potassium iodide, and iodine. Whether tissue or spores react to this reagent is vital for the correct identification of some mushrooms.
Meitnerium is a synthetic chemical element; it has symbol Mt and atomic number 109. It is an extremely radioactive synthetic element (not naturally occurring, but can be created in a laboratory). The most stable known isotope, meitnerium-278, has a half-life of 4.5 seconds, although the unconfirmed meitnerium-282 may have a longer half-life of 67 seconds. The element was first synthesized in August 1982 by the GSI Helmholtz Centre for Heavy Ion Research near Darmstadt, Germany, and it was named after the Austrian-Swedish nuclear physicist Lise Meitner in 1997. In the periodic table, meitnerium is a d-block transactinide element. It is a member of the 7th period and is placed in the group 9 elements, although no chemical experiments have yet been carried out to confirm that it behaves as the heavier homologue to iridium in group 9 as the seventh member of the 6d series of transition metals. Meitnerium is calculated to have properties similar to its lighter homologues, cobalt, rhodium, and iridium.
Blocking LRP5 expression using siRNA against LRP5 resulted in a significant decrease in MMP13 mRNA and protein expressions. The catabolic role of LRP5 appears to be mediated by the Wnt/beta-catenin pathway in human osteoarthritis. The polyphenol curcumin increases the mRNA expression of LRP5.
=== Diet === People with autoimmune hyperthyroidism (such as in Graves' disease) should not eat foods high in iodine, such as edible seaweed and seafood. From a public health perspective, the general introduction of iodized salt in the United States in 1924 resulted in lower rates of disease and goiters, and improved the lives of children whose mothers would not have eaten enough iodine during pregnancy, which would have lowered the IQs of their children.
Sources: en.wikipedia.org
The Jardin des Plantes is the home of the main galleries of the MNHN, and a division of the museum, which was born there. The garden was founded by Louis XIII 1635 as the Royal Garden of medicinal plants, under the direction of the royal physician. In the early 18th century, the chateau of the gardens was enlarged to house the collections of the royal pharmacist. In 1729, this collection was broadened into the Cabinet of Natural History, destined to receive the Royal collections dedicated to zoology and mineralogy. New plants and animal species were collected from around the world, examined, illustrated, classified, named and described in publications which were circulated across Europe and to America. An amphitheatre was constructed in the garden in 1787 to provide a venue for lectures and classes on the new discoveries. New greenhouses were built beginning in 1788, and the size of the gardens was doubled. The gardens served as the laboratory of scientists including Jean Baptiste Lamarck, author of the earliest theory of evolution, and were a base for major scientific expeditions by Nicolas Baudin, Alexander von Humboldt, Jules Dumont d'Urville and others throughout the 18th and 19th century. The gardens today include a large formal garden planted in geometric designs; and two enormous greenhouses, keeping tropical plants at a steady temperature of 22 degrees Celsius. The Alpine gardens present plants coming from Corsica, the Caucasus, North American and the Himalaya. The gardens of the School of Botany contain 3,800 species of plants, displayed by genre and family.
The Bergmann degradation is a series of chemical reactions designed to remove a single amino acid from the carboxylic acid (C-terminal) end of a peptide. First demonstrated by Max Bergmann in 1934, it is a rarely used method for sequencing peptides. The later developed Edman degradation is an improvement upon the Bergmann degradation, instead cleaving the N-terminal amino acid of peptides to produce a hydantoin containing the desired amino acid. The Bergmann degradation follows the earlier work of Bergmann and his close colleague Leonidas Zervas, combining the organic azide degradation of the Curtius rearrangement with the Bergmann-Zervas carbobenzoxy method, which they designed to occur under relatively mild conditions so as to allow peptide sequencing. A single round of the Bergmann degradation yields an aldehyde containing the sought after amino acid residue and the remaining fragment of the original peptide in amide form.
In 2001, the World Health Organization reported that data from Kosovo was inconclusive and called for further studies. That same year, governments of several European countries, particularly Italy, reported an increase in illnesses and developments of cancers among veterans that served in Balkan peacekeeping missions. A 2003 study by the United Nations Environment Programme (UNEP) in Bosnia and Herzegovina stated that low levels of contaminant were found in drinking water and air particulate at DU penetrator impact points. The levels were stated as not a cause for alarm. Yet, Pekka Haavisto, chairman of the UNEP DU projects stated, "The findings of this study stress again the importance of appropriate clean-up and civil protection measures in a post-conflict situation." A team of Italian scientists from the University of Siena reported in 2005 that, although DU was "clearly" added to the soil in the study area, "the phenomenon was very limited spatially and the total uranium concentrations fell within the natural range of the element in soils.
=== Cancer === In response to a report of precancerous changes in the pancreases of rats and organ donors treated with the DPP-4 inhibitor sitagliptin, the US FDA and the European Medicines Agency each undertook independent reviews of all clinical and preclinical data related to the possible association of DPP-4 inhibitors with pancreatic cancer. In a joint letter to the New England Journal of Medicine, the agencies stated that they had not yet reached a final conclusion regarding a possible causative relationship. A 2014 meta-analysis found no evidence for increased pancreatic cancer risk in people treated with DPP-4 inhibitors, but owing to the modest amount of data available, the authors were unable to completely exclude possibly increased risk.
Anaerobic respiration is used by microorganisms, either bacteria or archaea, in which neither oxygen (aerobic respiration) nor pyruvate derivatives (fermentation) are the final electron acceptor. Rather, an inorganic acceptor such as sulfate (SO2−4), nitrate (NO−3), or sulfur (S) is used. Such organisms are found in unusual environments such as underwater caves or near hydrothermal vents at the bottom of the ocean, in digestive tracts, as well as in anoxic soils or sediment in wetland ecosystems. In July 2019, a scientific study of Kidd Mine in Canada discovered sulfur-breathing organisms which live 7900 feet (2400 meters) below the surface. These organisms are also remarkable because they consume minerals such as pyrite as their food source.
Sources: en.wikipedia.org
By 8 May 1945, the 8th, 9th, and 15th Air Force's P-51 groups claimed some 4,950 aircraft shot down (about half of all USAAF claims in the European theater, the most claimed by any Allied fighter in air-to-air combat) and 4,131 destroyed on the ground. Losses were about 2,520 aircraft. In air combat, the top-scoring P-51 units (both of which exclusively flew Mustangs) were the 357th Fighter Group of the 8th Air Force with 565 air-to-air combat victories and the 9th Air Force's 354th Fighter Group with 664, which made it one of the top-scoring fighter groups. The top Mustang ace was the USAAF's George Preddy, whose final tally stood at 26.83 victories (a number that includes shared one half- and one third victory credits), 23 of which were scored with the P-51. Preddy was shot down and killed by friendly fire on Christmas Day 1944 during the Battle of the Bulge.
=== Exon 3 === Studies have identified a GHBP isoform that exists due to gene polymorphism, or variable expression of the allele. These isoforms differ based on whether or not the extracellular domain of GHR includes the amino acids encoded by exon 3 - exon 3 is either kept (dominant) or spliced out (recessive). As human are diploid, they may genotype as homozygous dominant (two copies of the allele retain exon 3), heterozygous (one copy with Exon 3, and one without), or homozygous recessive (two copies of the allele without exon 3). Studies have shown that the two isoforms can co-exist as dimerized GH receptors, as E3+/E3+, E3+/E3-, or E3-/E3-. Furthermore, the two isoforms both exist in the blood as GHBP. However, they may have separate functions that are poorly understood. The presence or absence of exon 3 in humans is individual-specific, but one study suggests that gender may play a role in this variable splicing, as females were shown to express higher levels of deleted-exon 3 GHBP in their blood. The evolutionary reason for exon-3 variable GHBP expression has not clearly be defined, and the isoforms in the blood have not been shown to differ with respect to GH affinity, which is unusual for an isoform that is missing an entire exon.
== Adsorption solar heating and storage == The low cost ($200/ton) and high cycle rate (2,000 ×) of synthetic zeolites such as Linde 13X with water adsorbate has garnered much academic and commercial interest recently for use for thermal energy storage (TES), specifically of low-grade solar and waste heat. Several pilot projects have been funded in the EU from 2000 to the present (2020). The basic concept is to store solar thermal energy as chemical latent energy in the zeolite. Typically, hot dry air from flat plate solar collectors is made to flow through a bed of zeolite such that any water adsorbate present is driven off. Storage can be diurnal, weekly, monthly, or even seasonal depending on the volume of the zeolite and the area of the solar thermal panels. When heat is called for during the night, or sunless hours, or winter, humidified air flows through the zeolite. As the humidity is adsorbed by the zeolite, heat is released to the air and subsequently to the building space. This form of TES, with specific use of zeolites, was first taught by John Guerra in 1978.
=== 2 May === Russia claimed to have taken Berdychi, near Avdiivka. It also claimed to have shot down a drone over Crimea. Two people were killed in separate Russian attacks in Donetsk and Kharkiv Oblasts.
Sources: en.wikipedia.org
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.
Thymosin alpha-1 is a single defined 28-residue peptide, while the broader family includes unrelated peptides such as thymosin beta-4. The shared name reflects historical isolation from thymus tissue rather than a common structure. Confusion between the two is common in older literature.
No single pathway fully accounts for its reported effects. Several studies describe interaction with innate immune receptors and downstream cytokine changes, but the complete picture is not settled. Open questions remain about which effects occur at physiological concentrations.
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.