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.
Reviewed 2025-12-07. Anything still debated is marked as such rather than presented as settled.
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。
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.
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.
| 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 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 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.
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.
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.
=== Protactinium-234m === Protactinium-234m is a member of the uranium series with a half-life of 1.17 minutes. It was discovered in 1913 by Kazimierz Fajans and Oswald Helmuth Göhring, who named it brevium for its short half-life. It is now believed that all decays of the parent thorium-234 produce this isomer and the ground state is observed because of (invisible) IT decay. Protactinium-234m has the same mass (same number of protons and neutrons) as protactinium-234, the difference merely visible in their non-identical half-life, with protactinium-234m having a noticeably shorter lifespan. This phenomenon is called nuclear isomerism.
==== Implications for cardiovascular disease and therapeutics ==== The dual extracellular and intracellular actions of PTHrP make it a promising target for cardiovascular therapies. Given its role in regulating cardiac cell growth and vascular integrity, modulating PTHrP expression or its intracellular signaling pathways could be beneficial in conditions such as heart failure, atherosclerosis, and ischemic heart disease. Additionally, therapeutic strategies that enhance intracrine PTHrP activity could improve angiogenesis and myocardial repair following injury. In conclusion, PTHrP is a key intracrine regulator in the cardiovascular system, influencing both myocardial and vascular function. Its ability to act within the nucleus and cytoplasm of cardiac cells highlights its potential as a therapeutic target for cardiovascular diseases. Future research focusing on the intracrine mechanisms of PTHrP may provide novel insights into cardiac regeneration and vascular remodeling.
Among Sporck's cost control efforts was his offshore outsourcing of labour. National Semiconductor was among the pioneers in the semiconductor industry to invest in facilities to perform final manufacturing operations of integrated circuits in developing countries, especially in Southeast Asia. National Semiconductor's manufacturing improvements under Sporck (in collaboration with Lamond) was enabled not by emphasizing process innovation but by improving and standardizing processes already established by other companies like Fairchild and Texas Instruments, as well as by frequent raiding to hire from Fairchild's pool of talents.
Sources: en.wikipedia.org
Subcutaneous adipose tissue is also a source of mesenchymal stem cells and have demonstrated positive outcomes in terms of cardiovascular tissue remodeling. Mammal hearts also host naturally occurring cardiac stem cells which may be capable of differentiating themselves into cardiomyocytes, endothelial cells and cardiac fibroblasts. This self-regeneration capacity gives rise to alternatives to classical cellular therapies whereby administration of growth factors such as Thymosin β4 for cell activation and migration are solely necessary. Largely democratized in terms of population information, embryonic stem cells are known for their strong capacity for expansion and differentiation into cardiomyocytes, endothelial cells and cardiac fibroblasts. However, if non autologous, immunosuppression therapy is associated with such treatment. Hence, research has been focused on induced pluripotent stem cells (iPSCs) from somatic human tissue. Further to cell and necessary relevant growth factor selection, cell delivery is an important issue. Indeed, the intracoronary route is the most straightforward cell delivery route as associated with intramyocardial cellular retention; retention rates are however low, i.e. exceed 10%. Washed off cells reach other organs or die, which can be an issue at the time of prepare ICH module 8. Other alternative injection routes have been studied, namely injection via sternotomy, endomyocardial and intracoronary routes.
=== Transthyretin-related hereditary amyloidosis === The FDA granted Patisiran (Onpattro) orphan drug status and breakthrough therapy designation due to its novel mechanism involving RNA therapy to block the production of an abnormal form of transthyretin. Patisiran received full FDA approval in 2018 and its RNA lipid nanoparticle drug delivery system was later used in the Pfizer–BioNTech COVID-19 vaccine and Moderna RNA vaccines.
== Further reading == Zachara, Natasha; Akimoto, Yoshihiro; Hart, Gerald W. (2015), Varki, Ajit; Cummings, Richard D.; Esko, Jeffrey D.; Stanley, Pamela (eds.), "The O-GlcNAc Modification", Essentials of Glycobiology (3rd ed.), Cold Spring Harbor Laboratory Press, PMID 28876858.
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。
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.