If you have been reading about reconstitution 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 2026-01-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Acetylated peptide | N-terminal acetyl group blocks aminopeptidase attack |
| Residue count | 28 amino acids | Matches the N-terminus of prothymosin alpha |
| Molecular mass | About 3,108 Da | Value for the free, unmodified peptide |
| Isoelectric point | Approximately 4.2 | Acidic; net negative charge at neutral pH |
| Encoding gene | PTMA | Human gene for the precursor protein |
Thymosin alpha 1 is a synthetic 28-amino-acid peptide first isolated in 1966 from thymosin fraction 5, a bovine thymus extract. Its chain begins with an acetylated serine residue and ends with asparagine. The native peptide carries a molecular mass near 3,108 daltons. Researchers classify it as an immunomodulatory agent rather than a hormone with a single endocrine target. Early work framed it as a thymus-derived factor that supports T-cell maturation. The synthetic form used in research and clinical products matches the natural sequence.
Immune signaling studies link thymosin alpha 1 to Toll-like receptor pathways, particularly TLR2 and TLR9, on dendritic cells and other antigen-presenting cells. Activation of these receptors promotes maturation of T cells and increases natural killer cell activity. The peptide shifts cytokine output toward a T helper 1 profile, raising interferon gamma and interleukin 2 while modulating interleukin 10. Whether these effects translate into clinical benefit for any specific disease remains a subject of debate. Reported outcomes vary across trials and populations.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
Ondarza RN, Abney R, Lopez-Colome AM (1969). "Characterization of a NADPH-dependent coenzyme A-SS-glutathione reductase from yeast". Biochim. Biophys. Acta. 191 (2): 239–48. doi:10.1016/0005-2744(69)90243-5. PMID 4390951. Ondarza RN, Escamilla E, Gutierrez J, De la Chica G (1974). "CoAS-Sglutathione and GSSG reductases from rat liver. Two disulfide oxidoreductase activities in one protein entity". Biochim. Biophys. Acta. 341 (1): 162–71. doi:10.1016/0005-2744(74)90076-x. PMID 4151341. Carlberg I, Mannervik B (1977). "Purification by affinity chromatography of yeast glutathione reductase, the enzyme responsible for the NADPH-dependent reduction of the mixed disulfide of coenzyme A and glutathione". Biochim. Biophys. Acta. 484 (2): 268–74. doi:10.1016/0005-2744(77)90083-3. PMID 334266.
== Development and production == Pimecrolimus was developed by Novartis. Its development number was ascomycin derivative ASM 981. The New Drug Application (NDA) was filed December 15, 2000. It received US FDA approval on December 13, 2001. At its US approval, it was one of the first new eczema treatments introduced since the topical corticosteroids of the 1950s. It is available as a topical cream, once marketed by Novartis. Since early 2007, Galderma has been promoting the compound in Canada. The trade name is Elidel.
== Inferior == The inferior tarsus (tarsus inferior; inferior tarsal plate) is smaller, is thin, is elliptical in form, and has a vertical diameter of about 5 mm (0.2 in). The free or ciliary margins of these plates are thick and straight.
Sources: en.wikipedia.org
== War period, 1938–1945 == When the committee was outlawed in September 1937, six of its members were deported, its president Amin al-Husayni managed to escape arrest and went into exile in Beirut. Jamal al-Husayni escaped to Syria. Three other members were deported to the Seychelles, and other members moved into voluntary exile in neighbouring countries. Al-Hadi, who was out of the country at the time, was not allowed to return. Membership of the outlawed committee had dwindled to Jamal al-Husayni (acting chairperson), Husayn al-Khalidi (secretary), Ahmed Hilmi Pasha and Emil Ghuri. For all practical purposes, the committee ceased to exist, however, this brought little change in the structure of Arab political life and the Palestinian revolt continued. With the indications of a new European war on the horizon, and in an endeavor to resolve the inter-communal issues in Palestine, the British government proposed in late 1938 a conference in London of the two Palestinian communities. Some Arab leaders welcomed the proposed London Conference but indicated that the British would need to deal with the disbanded Arab Higher Committee and with Amin al-Husayni. On 23 November 1938, the Colonial Secretary, Malcolm MacDonald, repeated his refusal to allow Amin al-Husayni to be a delegate, but was willing to allow the five Palestinian leaders held in the Seychelles to take part in the conference.
=== Formate dehydrogenase === Some microorganisms utilize selenium in formate dehydrogenase. Formate is produced in large amounts in the hepatic (liver cells) mitochondria of embryonic cells and in cancer cells by the folate cycle. Formate is reversibly oxidized by the enzyme formate dehydrogenase:
Traditional chemotherapeutic agents are cytotoxic by means of interfering with cell division (mitosis) but cancer cells vary widely in their susceptibility to these agents. To a large extent, chemotherapy can be thought of as a way to damage or stress cells, which may then lead to cell death if apoptosis is initiated. Many of the side effects of chemotherapy can be traced to damage to normal cells that divide rapidly and are thus sensitive to anti-mitotic drugs: cells in the bone marrow, digestive tract and hair follicles. This results in the most common side-effects of chemotherapy: myelosuppression (decreased production of blood cells, hence that also immunosuppression), mucositis (inflammation of the lining of the digestive tract), and alopecia (hair loss). Because of the effect on immune cells (especially lymphocytes), chemotherapy drugs often find use in a host of diseases that result from harmful overactivity of the immune system against self (so-called autoimmunity). These include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, vasculitis, malignant hypertension and many others.
Sources: en.wikipedia.org
In the Constituent Assembly of India debates between 1946 and 1949, India's founders strongly preferred birthplace citizenship, viewing it as more democratic than basing rights on race or descent. While India’s 1950 constitution originally offered palliative measures to those displaced by the Partition, the Citizenship Act of 1955 formally established birthplace as the foundation for Indian citizenship. More recently, India's new citizenship laws have shifted to favour bloodline over birthplace, creating legal obstacles for new or marginalised groups to experience substantive equality. The Lok Sabha, India’s lower house of parliament, has 543 members directly elected by citizens aged 18 and older, with specific seats reserved to ensure fair representation for Scheduled Castes and Scheduled Tribes. However, its legislative productivity has significantly declined over the decades, with the average number of working days dropping from 121 days per year in the 1950s to 68 days between 2000 and 2023. In addition, more meeting time is lost to disruptions. The Rajya Sabha, India’s upper house of parliament, serves as a federal chamber where state legislatures elect members through a system that balances state size with minimum representation for smaller regions. However, historical data shows that most members serve only a single term, suggesting that political party leaders sometimes use these seats to reward favourites.
Additional conservation efforts for the tree involve fencing against livestock, watering of seedlings in open areas, and involving local communities in planting seedlings. By the 21st century threats arising from global warming and overgrazing have made it difficult for new trees to grow in wild. A collaboration of local people with assistance from others such as UK-based Friends of Socotra and Mendel University in Brno has been aiding a number of slow growing saplings by watering them while they are too young to draw down sufficient water, and protecting them from hungry goats. As of 2022, about 600 saplings have reached the point where they no longer need regular watering, leading to hopes that a new generation of the tree may become established on Socotra.
Fish and shellfish have a natural tendency to concentrate inorganic and organic toxins and pollutants in their bodies, including methylmercury, a highly toxic organic compound of mercury, polychlorinated biphenyls (PCBs), and microplastics. Species of fish that are high on the food chain, such as shark, swordfish, king mackerel, albacore tuna, and tilefish contain higher concentrations of these bioaccumulates. This is because bioaccumulates are stored in the muscle tissues of fish, and when a predatory fish eats another fish, it assumes the entire body burden of bioaccumulates in the consumed fish. Thus species that are high on the food chain amass body burdens of bioaccumulates that can be ten times higher than the species they consume. This process is called biomagnification. Man-made disasters can cause localized hazards in seafood which may spread widely via piscine food chains. The first occurrence of widespread mercury poisoning in humans occurred this way in the 1950s in Minamata, Japan. Wastewater from a nearby chemical factory released methylmercury that accumulated in fish which were consumed by humans. Severe mercury poisoning is now known as Minamata disease. The 2011 Fukushima Daiichi Nuclear Power Plant disaster and 1947–1991 Marshall Islands nuclear bomb testing led to dangerous radionuclide contamination of local sea life which, in the latter case, remained as of 2008.
Sources: en.wikipedia.org
Thymosin fraction 5 is a mixture of many peptides obtained from thymus tissue, while thymosin alpha 1 is a single defined 28-residue molecule. The two names appear together in older literature because the purified peptide was first obtained from that mixture.
The precursor, prothymosin alpha, is encoded by the PTMA gene in humans. The 28-residue peptide corresponds to the N-terminal segment released from that larger protein.
It is produced as a fragment of prothymosin alpha and is present in many tissues. Circulating concentrations are low, which makes routine measurement difficult.
Lyophilized powder is normally kept at minus twenty degrees Celsius or below, in a sealed container, desiccated and away from light. Reconstituted solutions are less stable and are usually refrigerated and used quickly. Repeated temperature cycling should be avoided.