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 2025-09-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
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.
| Property | Value | Notes |
|---|---|---|
| 化学分类 | 线性肽 | 由28个氨基酸组成 |
| 分子量 | 约3108 Da | 合成版本一致 |
| 外观 | 白色至类白色粉末 | 冻干品 |
| 溶解度 | 易溶于水 | 微溶于有机溶剂 |
| 储存温度 | -20°C（冻干） | 溶解后2-8°C |
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.
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.
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.
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.
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.
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.
Acetyl (Ac), Benzoyl (Bz) groups — common in oligonucleotide synthesis for protection of N4 in cytosine and N6 in adenine. Removed by base, often aqueous or gaseous ammonia or methylamine. Too stable to readily remove from aliphatic amides. Troc (trichloroethoxycarbonyl) group – Removed by Zn insertion in the presence of acetic acid Tosyl (Ts) group – Removed by concentrated acid (HBr, H2SO4) & strong reducing agents (sodium in liquid ammonia or sodium naphthalenide) Other sulfonamide (Nosyl & Nps) groups — Removed by samarium iodide, thiophenol or other soft thiol nucleophiles, or tributyltin hydride Benzylamines:
The basis of bone tissue engineering is that the materials will be resorbed and replaced over time by the body's own newly regenerated biological tissue. Tissue engineering is not only limited to the bone: a large amount of research is devoted to cartilage, ligament, skeletal muscle, skin, blood vessel, and neural tissue engineering as well.
=== Pigmentation === UV exposure can also lead to inflammation and vasodilation, which is clinically manifested as sunburn. UV radiation activates the transcription factor NF-κB, which is the first step in inflammation. NF-κB activation results in the increase of proinflammatory cytokines, for example, interleukin 1 (IL-1), IL-6, vascular endothelial growth factor, and tumor necrosis factor (TNF-α). This then attracts neutrophils, which lead to an increase in oxidative damage through the generation of free radicals. Additionally, UV radiation would cause the down-regulation of an angiogenesis inhibitor, thrombospondin-1, and the up-regulation of an angiogenesis activator, which is platelet-derived endothelial cell growth factor, in keratinocytes. These enhance angiogenesis and aid in the growth of UV-induced neoplasms.
Sources: en.wikipedia.org
=== Disadvantages === The used fuel is difficult and dangerous to reprocess because many of the daughters of 232Th and 233U are strong gamma emitters. All 233U production methods result in impurities of 232U, either from parasitic knock-out (n,2n) reactions on 232Th, 233Pa, or 233U that result in the loss of a neutron, or from double neutron capture of 230Th, an impurity in natural 232Th:
On 2 March, the US embassy in Kuwait was struck and closed indefinitely. The US-flagged tanker Stena Imperative and the Honduras-flagged tanker Athe Nova were struck. An advisor to an IRGC commander said he would set fire to any ship coming through the Strait of Hormuz, and added that no oil would leave the area. Qatari air defenses shot down two Iranian Su-24 bombers. The Qatari Ministry of Defense announced that Ras Laffan Industrial City, the main Qatari gas facility, and Mesaieed Industrial Area were struck by Iranian drones. According to satellite imagery analysis by the Energy Economics and Society Research Institute, Ras Laffan appeared to not have been damaged before the "unprecedented shutdown" which sent fuel prices higher. The US and Israel attacked the Natanz Nuclear Facility and the Iranian media reported damage to the Khatam-al-Anbia and Gandhi hospitals. In a friendly fire incident, the pilot of an F/A-18 of the Kuwait Air Force shot down three US F-15E fighters. Israel and Hezbollah exchanged strikes. Hezbollah began firing rockets and missiles on Israel in retaliation for the killing of Khamenei. Hezbollah claimed that the attack was a "defensive act" after more than a year of Israeli attacks despite a 2024 truce. It added that it restarted fighting to force Israel to stop its aggression and evacuate from seized Lebanese territories, emphasizing that the move was unrelated to the war. Lebanon banned military activities by Hezbollah after the attacks.
==== Miscellaneous laurasiatherian research ==== A study on the preservation of different kinds of steroids in bones of Ashoroa laticosta, Behemotops katsuiei and an unidentified whale from the Oligocene Morawan Formation (Japan) is published by Umamaheswaran et al. (2026). Matsui, Mitoh & Tsubamoto (2026) identify a purported humerus of a member of the genus Behemotops from the Miocene Chikubetsu Formation (Japan) as actually belonging to a juvenile member of the genus Desmostylus, and interpret the specimen as indicating that members of the genus Desmostylus expanded their range across Hokkaido during the Middle Miocene Climatic Optimum. Kramarz & Bond (2026) revise the composition of astrapothere assemblages from the Las Flores Formation (Argentina). Evidence of gradual increase of body mass of macraucheniids throughout their evolutionary history, likely linked to climate changes, is presented by Lobo, Gelfo & de Azevedo (2026). Wilson et al. (2026) determine that early hypsodont notoungulates from the Oligocene Tinguiririca Fauna (Chile) lived in an open, woody habitat, interpret the tooth wear of the studied notoungulates as consistent with a browsing diet, and interpret the evolution of their hypsodonty as unrelated to the expansion of grasslands. Redescription of the anatomy of Puelia plicata is published by Vera, Folino & Scarano (2026). A study on the phylogenetic relationships of toxodontid notoungulates is published by Armella & Deforel (2026). Armella et al.
Sources: en.wikipedia.org
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。
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.