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 2026-05-25 and is reviewed periodically as new material appears.
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 short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
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。
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 3,108 Da | Consistent with a 28-residue acetylated peptide |
| Residue count | 28 | Corresponds to the amino terminal region of prothymosin alpha |
| Appearance of dry powder | White to off-white solid | Slight variation between lots is normal |
| Solubility class | Freely soluble in water | Low solubility in most organic solvents |
| Common synonyms | Thymosin alpha 1, T alpha 1 | The numeral reflects an early fraction numbering scheme |
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
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.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
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.
Different functional groups have different pKa values and bond strengths (single, double, triple) leading to increased electrophilicity with lower pKa and increased nucleophile strength with higher pKa. More basic/nucleophilic functional groups desire to attack an electrophilic functional group with a lower pKa on another molecule (intermolecular) or within the same molecule (intramolecular). Any group with a net acidic pKa that gets within range, such as an acyl or carbonyl group is fair game. Since the likelihood of being attacked decreases with an increase in pKa, acyl chloride components with the lowest measured pKa values are most likely to be attacked, followed by carboxylic acids (pKa = 4), thiols (13), malonates (13), alcohols (17), aldehydes (20), nitriles (25), esters (25), then amines (35). Amines are very basic, and are great nucleophiles/attackers.
Paregoric, or camphorated tincture of opium, also known as tinctura opii camphorata, is a patent medicine known for its antidiarrheal, antitussive, and analgesic properties. According to Goodman and Gilman's 1965 edition, "Paregoric is a 4% opium tincture in which there is also benzoic acid, camphor, and anise oil. ... Paregoric by tradition is used especially for children." The term paregoric, which comes from Ancient Greek παρηγορικός parēgorikós "soothing", has also been used for boiled sweets which contained the substance, in particular the Army & Navy brand.
8 October – Conservative Party leader Kemi Badenoch delivers her keynote speech to the Conservative Party Conference on its final day. 9 October – Kensington Palace announces that Prince William will attend the COP30 conference in Brazil in November. Former prime minister Rishi Sunak takes up paid adviser roles with Microsoft and Anthropic, the earnings from which will be donated to the charity to tackle numeracy problems in the UK that he and his wife founded. Councillor Rowland O'Connor resigns as deputy leader of the Reform UK group on Cornwall Council. 10 October – Ash Regan resigns from the Alba Party in order to "focus" on her efforts to criminalise prostitution. Bristol City councillor Fabian Breckels is suspended from the Labour Party over an alleged racist comment posted on Facebook. 12 October – Starmer arrives in Egypt ahead of an international summit on the Gaza peace process where Downing Street says he will pay "particular tribute" to the US president, Donald Trump. 13 October – MI5 warns MPs they are being targeted in espionage operations by Russia, China and Iran. The Scottish National Party conference is held in Aberdeen. Councillor Rob Parsonage resigns as leader of the Reform UK group on Cornwall Council. 14 October – The Northern Ireland Troubles Bill, designed to replace the Northern Ireland Troubles (Legacy and Reconciliation) Act 2023, receives its first reading in the House of Commons.
Sources: en.wikipedia.org
Another form of recognized duplex invasion at targeted sequence can occur in dsDNA containing mixed T–C sequences. This form of duplex invasion is achieved through a complementary sequence of homopurine PNA oligomers. This triplex is formed from a PNA-DNA hybrid that binds anti-parallel with the complementary DNA sequence and results in a displaced non-complementary DNA strand. Additionally, PNA can be modified to form "clamp" triplex structures at the target site. One type of "clamp" formed is a bis-PNA structure, in which two PNA molecules are held together by a flexible linker such as 8-amino-3,6-dioxaoctanoic acid (O). The bis-PNA structure forms a PNA-DNA-PNA triplex at the target site, where one strand forms Watson-Crick base pairs with DNA in an antiparallel orientation and the other strand forms Hoogsteen base pairs with the homopurine DNA strand in the DNA-PNA duplex. A tail clamp PNA (tcPNA) is also another form of triplex clamp that can also be formed. TcPNAs contain an extended 5-10 bp tail that forms a PNA/DNA duplex in addition to a PNA-DNA-PNA "clamp". This allows for more specified PNA binding without the need for a homopyrimidie/pyridine stretch. These clamp structures had been shown to have high affinity and specificity. The addition of lysine residues to either or both ends of PNA's could be used to increase cellular uptake and binding.
=== Databases of orthologous genes and de novo orthology inference tools === Given their tremendous importance for biology and bioinformatics, orthologous genes have been organized in several specialized databases that provide tools to identify and analyze orthologous gene sequences. These resources employ approaches that can be generally classified into those that use heuristic analysis of all pairwise sequence comparisons, and those that use phylogenetic methods. Sequence comparison methods were first pioneered in the COGs database in 1997. These methods have been extended and automated in twelve different databases the most advanced being AYbRAH Analyzing Yeasts by Reconstructing Ancestry of Homologs as well as these following databases right now. Some tools predict orthologous de novo from the input protein sequences, might not provide any Database. Among these tools are SonicParanoid and OrthoFinder.
== Analogue controls == Several jurisdictions have implemented analogue law controls of fentanyl analogues in an attempt to pre-emptively ban novel derivatives before they appear on the market. One representative example is the New Zealand provisions enacted in 1988 in response to the first wave of fentanyl derivatives. This bans a set of structures as follows; "Fentanyl analogues, in which the N-[1-(2-phenethyl)-4-piperidyl]aniline nucleus has additional radicals, either alone or in combination, attached as follows: (a) an acetyl, propionyl, butenoyl or butanoyl radical, attached to the aniline nitrogen atom: (b) 1 or more alkyl radicals, with up to 10 carbon atoms in total, attached to the ethyl moiety: (c) any combination of up to 5 alkyl radicals and/or alkoxy radicals (each with up to 6 carbon atoms, including cyclic radicals) and/or halogen radicals, attached to each of the benzene rings." A more recent and somewhat broader example was introduced into US Federal legislation in 2018, covering the following structures; "...fentanyl-related substances includes any substance not otherwise controlled in any schedule...that is structurally related to fentanyl by one or more of the following modifications:
Sources: en.wikipedia.org
The name reflects an early convention for naming thymus-derived fractions. The peptide is characterized and measured as a defined molecule, and it does not operate through a single classical endocrine axis.
它不是经典的内分泌激素，而是一种免疫调节肽。其作用主要通过局部免疫细胞间的信号传递实现，而非经血液循环作用于远隔器官。
天然胸腺素α1主要从胸腺组织提取，也可在脾脏和淋巴结中检出。目前研究和临床使用的多为化学合成版本，不再依赖动物组织。
胸腺素组分5是牛胸腺提取物的粗组分，包含多种肽。胸腺素α1是其中一种被纯化和表征的单一肽，具有明确的28个氨基酸序列。