If you have been reading about thymalfasin 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 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 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 |
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.
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.
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.
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.
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。
=== Structure Stabilization Improvements === DNA brick structures can be used to synthesize various and specific geometries that serve as tools in biological studies. Due to their nucleotide nature, they can quickly dissociate under environmental fluctuations during assembly, in the presence of low concentrations of divalent cations, and in the presence of nucleases. Various methods have been developed to protect and stabilize the DNA structures. However, such methods require the encapsulation of the nanostructure making accessing DNA strands difficult and leading to covalent crosslinking. Kim and Yi presented a stabilization method involving the synthesis of DNA brick nanostructure with dendritic oligonucleotides attached to the outer surface which maintain the DNA accessibility and prevent nuclease digestion. Certain DNA brick motifs remain structurally stable at low divalent salt concentrations and in the presence of nucleases. They demonstrated that neither chemical protectants nor covalent base pair interlocking was necessary to maintain the DNA brick structure stability, especially structures with binding domain lengths of 13 nucleotides or longer. Likewise, coating their surfaces with dendritic oligonucleotides prevented the usage of chemical base-pair interlocking techniques and encapsulation methods as they could still display structural stability in cellular media and made it possible to access the DNA sequences at the surface.
D-dimer (or D dimer) is a dimer that is a fibrin degradation product (FDP), a small protein fragment present in the blood after a blood clot is degraded by fibrinolysis. It is so named because it contains two D fragments of the fibrin protein joined by a cross-link, hence forming a protein dimer. D-dimer concentration may be determined by a blood test to help diagnose thrombosis. Since its introduction in the 1990s, it has become an important test performed in people with suspected thrombotic disorders, such as venous thromboembolism. While a negative result practically rules out thrombosis, a positive result can indicate thrombosis but does not exclude other potential causes. Its main use, therefore, is to exclude thromboembolic disease where the probability is low. D-dimer levels are used as a predictive biomarker for the blood disorder disseminated intravascular coagulation and in the coagulation disorders associated with COVID-19 infection. A four-fold increase in the protein is an indicator of poor prognosis in people hospitalized with COVID-19.
== Film == On February 6, 2013, while speaking at the 2013 DICE conference about storytelling in games and film, J. J. Abrams and Gabe Newell announced that they had plans for a game and a film collaboration. Abrams said, "There's an idea we have for a game that we'd like to work with Valve on," while Newell said, "We're going to figure out if we can make a Portal movie or Half-Life movie together". In an interview in March 2016, Abrams stated that while he has been working on many other projects since, he still has plans to direct these films in the future, with both films in the writing stage.
Sources: en.wikipedia.org
== Uses == In industry, hexanes are used in the formulation of glues for shoes, leather products, and roofing. They are also used to extract cooking oils (such as canola oil or soybean oil) from seeds, for cleansing and degreasing a variety of items, and in textile manufacturing. A typical laboratory use of hexanes is to extract oil and grease contaminants from water and soil for analysis. Since hexane cannot be easily deprotonated, it is used in the laboratory for reactions that involve very strong bases, such as the preparation of organolithiums. For example, butyllithiums are typically supplied as a hexane solution. Hexanes are commonly used in chromatography as a non-polar solvent. Higher alkanes present as impurities in hexanes have similar retention times as the solvent, meaning that fractions containing hexane will also contain these impurities. In preparative chromatography, concentration of a large volume of hexanes can result in a sample that is appreciably contaminated by alkanes. This may result in a solid compound being obtained as an oil and the alkanes may interfere with analysis. As an internal combustion engine fuel, n-hexane has low octane numbers; a research octane number of 24.8 and a motor octane number of 26. In 1983 its share in Japanese gasoline varied around 6%, in 1992 it was present in American gas between 1 and 3%, and in Swedish automobile fuel in the same year the share was consistently under 2%, often below 1%. By 2011 its share in US gas stood between 1 and 7%.
== UK appliance safety recalls == Following its 2014 acquisition of Indesit, Whirlpool identified a fire risk affecting certain vented and condensing tumble dryers sold in the United Kingdom under the Hotpoint, Indesit, Creda, Swan and Proline brands. The affected models had been manufactured between April 2004 and September 2015; lint could accumulate and come into contact with a heating element, creating a fire risk. Whirlpool told the House of Commons Business, Energy and Industrial Strategy Committee that 5.3 million affected machines had been manufactured for the UK market. Whirlpool began a modification programme in November 2015 rather than a full recall. Owners were initially advised that affected dryers could continue to be used under specified precautions, but the advice was changed in early 2017 to tell consumers not to use unmodified machines. In August 2016, a fire at Shepherds Court in Shepherd's Bush was attributed by the London Fire Brigade to an Indesit tumble dryer covered by Whirlpool's corrective-action programme. A House of Commons committee later criticised the decision not to initiate a full recall and the pace of the modification programme. In April 2019, the Office for Product Safety and Standards (OPSS) concluded that the risk of harm or injury from lint fires in dryers that had been modified was low, but required Whirlpool to improve aspects of its risk management and communication with consumers. Following further intervention by OPSS, Whirlpool agreed in July 2019 to recall remaining unmodified affected tumble dryers.
== Tissue distribution == IGFBP-3 mRNA is expressed in all tissue examined, with kidney, stomach, placenta, uterus and liver showing highest expression in rat tissues. Rat liver IGFBP-3 mRNA is found in nonparenchymal cells including sinusoidal endothelium, but not in hepatocytes. In contrast, human hepatocytes do express IGFBP-3.
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.