This is a working overview of thymosin alpha 1, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-11 and is reviewed periodically as new material appears.
Whether the free 28-residue peptide circulates in human tissue remains debated. The best-documented human source is prothymosin alpha, a larger acidic protein that carries the sequence at its N-terminus. Reports of measurable peptide levels in serum and lymphoid tissue exist, yet some of that signal may come from cross-reacting fragments or from the parent protein. Most reviews therefore treat prothymosin alpha as the established human molecule and describe independent circulation of the small peptide as an unresolved question.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
Thymosin alpha-1 is a synthetic 28-amino-acid peptide whose sequence was first identified in extracts of bovine thymus tissue during the 1970s. The chain carries an acetyl group on its N-terminal serine. Its acidic residue content is high, which produces strong water solubility and an isoelectric point well below neutrality. Material supplied for laboratory and clinical use is manufactured by solid-phase peptide synthesis rather than purified from animal tissue. Different salt forms, such as the acetate, alter the counter-ion content without changing the peptide backbone.
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 a short peptide first isolated from bovine thymus tissue in the early 1970s during fractionation work aimed at identifying factors that influence T cell development. It belongs to a family of acidic thymic peptides, and the original preparations contained several components that were later separated by chromatography. The compound is now produced synthetically rather than extracted from tissue, which removes batch variability tied to animal sourcing. Researchers describe it as an immunomodulatory peptide because laboratory studies show effects on several cell types of the innate and adaptive immune systems.
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.
| Property | Value | Notes |
|---|---|---|
| Amino acid length | 28 residues | Single chain with an acetylated N-terminus |
| Molecular mass | Approximately 3,108 Da | Small shifts occur with counter-ion and water content |
| Isoelectric point | Around 3.5 | Low value follows from the many acidic residues |
| Parent molecule | N-terminal region of prothymosin alpha | Free circulating form in humans is not firmly established |
| Common synonyms | Thymalfasin; T alpha 1 | Older literature also uses the full spelled-out form |
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
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 peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
Social and economic factors such as population change and the growth of international markets also have an effect on the number of people purchasing theater tickets, along with audience demographics where some films sell a much higher proportion of discounted children's tickets, or perform better in big cities where tickets cost more. The measuring system for gauging a film's success is based on unadjusted grosses, mainly because historically this is the way it has always been done because of the practices of the film industry: the box-office receipts are compiled by theaters and relayed to the distributor, which in turn releases them to the media. Converting to a more representative system that counts ticket sales rather than gross is also fraught with problems because the only data available for older films are the sale totals. As the motion picture industry is highly oriented towards marketing currently released films, unadjusted figures are always used in marketing campaigns so that new blockbuster films can much more easily achieve a high sales ranking, and thus be promoted as a "top film of all time", so there is little incentive to switch to a more robust analysis from a marketing or even newsworthy point of view. Despite the inherent difficulties in accounting for inflation, several attempts have been made. Estimates depend on the price index used to adjust the grosses, and the exchange rates used to convert between currencies can also affect the calculations, both of which can have an effect on the ultimate rankings of an inflation adjusted list.
== K == kainic acid receptor - kallidin - kappa opioid receptor - kappa-chain immunoglobulin - karyoplasm - karyotype - kelvin - keratin - kinase - kinesin - kinetic energy - kinetic exclusion assay - kinetics - knock-out mouse - Krebs cycle
Once in the brain, the principal mode of action is as a nonselective antagonist of adenosine receptors (in other words, an agent that reduces the effects of adenosine). The caffeine molecule is structurally similar to adenosine, and is capable of binding to adenosine receptors on the surface of cells without activating them, thereby acting as a competitive antagonist. In addition to its activity at adenosine receptors, caffeine is an inositol trisphosphate receptor 1 antagonist and a voltage-independent activator of the ryanodine receptors (RYR1, RYR2, and RYR3). It is also a competitive antagonist of the ionotropic glycine receptor.
De Gruyter. ISBN 978-3-11-042998-5. Keikhosravi, Adib; Bredfeldt, Jeremy S.; Sagar, Abdul Kader; Eliceiri, Kevin W. (2014). "Second-harmonic generation imaging of cancer". Quantitative Imaging in Cell Biology. Methods in Cell Biology. Vol. 123. pp. 531–546. doi:10.1016/B978-0-12-420138-5.00028-8. ISBN 978-0-12-420138-5. ISSN 0091-679X. PMID 24974046. Hanry Yu; Nur Aida Abdul Rahim (2013). Imaging in Cellular and Tissue Engineering, 1st edition. CRC Taylor&Francis. ISBN 978-0-367-44586-7. Cicchi, Riccardo; Vogler, Nadine; Kapsokalyvas, Dimitrios; Dietzek, Benjamin; Popp, Jürgen; Pavone, Francesco Saverio (2013). "From molecular structure to tissue architecture: collagen organization probed by SHG microscopy". Journal of Biophotonics. 6 (2): 129–142. doi:10.1002/jbio.201200092. PMID 22791562. Roesel, D.; Eremchev, M.; Schönfeldová, T.; Lee, S.; Roke, S. (2022-04-18). "Water as a contrast agent to quantify surface chemistry and physics using second harmonic scattering and imaging: A perspective". Applied Physics Letters. 120 (16). AIP Publishing: 160501. Bibcode:2022ApPhL.120p0501R. doi:10.1063/5.0085807. ISSN 0003-6951. S2CID 248252664.
In the skin, systemic sclerosis causes hardening and scarring. The skin may appear tight, reddish, or scaly. Blood vessels may also be more visible. Where large areas are affected, fat and muscle wastage may weaken limbs and affect appearance. Patients report severe and recurrent itching of large skin areas. The severity of these symptoms varies greatly among patients: Some having scleroderma of only a limited area of the skin (such as the fingers) and little involvement of the underlying tissue, while others have progressive skin involvement. Digital ulcers—open wounds especially on fingertips and less commonly the knuckles—are not uncommon.
Sources: en.wikipedia.org
=== Stickler syndrome === Several COL2A1 mutations cause Stickler syndrome, often leading to the production of a truncated protein that cannot be incorporated into collagen fibers. Many mutations introduce premature stop signals, resulting in a 50% reduction of pro-alpha1(II) collagen chains and underproduction of type II collagen in cartilage.
These collagen types can be directly or indirectly associated with fibrils at different affinities to modulate the frictional properties of fibril surfaces. In addition, collagen XIV association with a propeptide suggests FACIT function can extend to providing binding sites for fibril-modifying extracellular enzymes.
== Function == Type IV collagen is a type of collagen that is responsible for providing a scaffold for stability and assembly. It is also predominantly found in extracellular basement membranes. It aids in cell adhesion, migration, survival, expansion, and differentiation.
=== Nuclear weapons === When gram quantities of plutonium were first produced in the Manhattan Project, it was discovered that a minor isotope (240Pu) underwent significant spontaneous fission, which brought into question the viability of a plutonium-fuelled gun-type nuclear weapon. While the Los Alamos team began work on the implosion-type weapon to circumvent this issue, the Chicago team discussed reactor design solutions. Eugene Wigner proposed to use the 240Pu-contaminated plutonium to drive the conversion of thorium into 233U in a special converter reactor. It was hypothesized that the 233U would then be usable in a gun-type weapon, though concerns about contamination from 232U were voiced. Progress on the implosion weapon was sufficient, and this converter was not developed further, but the design had enormous influence on the development of nuclear energy. It was the first detailed description of a highly enriched water-cooled, water-moderated reactor similar to future naval and commercial power reactors. In 1943 the Manhattan Project contracted two private companies, Union Carbide and Chevron, to quietly compile a survey of uranium and thorium deposits around the world. The primary focus was uranium but early in the process thorium was also included. Deposits of monazite sands where identified in Brazil, Netherlands East Indies, and Travancore in India but none of these were pursued by the project. During the Cold War the United States explored the possibility of using 232Th as a source of 233U to be used in a nuclear bomb and it fired a test bomb in 1955.
Sources: en.wikipedia.org
It is usually described as an immunomodulatory peptide rather than a classic circulating hormone. No endocrine gland is known to release it as a primary secretory product, and its measured presence in blood is not firmly established.
Prothymosin alpha is a much larger acidic protein, roughly 111 to 113 residues long, and the thymosin alpha-1 sequence matches its N-terminal region. The small peptide is therefore best understood as a fragment of that parent protein rather than a separate gene product.
Trials and clinical reports have examined chronic hepatitis B and C, use as a vaccine adjuvant, and supportive treatment in some immunodeficiency and oncology settings. Results vary by indication, and regulatory approval differs between countries.
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.