This is a working overview of deamidation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-04-30. 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。
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。
Lyophilized material is generally held at reduced temperature to slow degradation, and storage at minus twenty degrees Celsius or lower is common practice for long-term retention. Short-term working portions are often kept between two and eight degrees Celsius. Once dissolved, the peptide is less stable than the dry powder, and repeated freeze-thaw cycles are associated with loss of material and with aggregate formation. Vials are usually allowed to reach room temperature before opening so that condensation does not introduce moisture, and solutions are protected from light where practical.
Identity and purity are assessed mainly by reversed-phase high-performance liquid chromatography, which separates the peptide from closely related impurities and from truncated or oxidized variants. Mass spectrometry supplies the molecular mass and confirms the expected sequence length, while amino acid analysis can be used to check composition. Because the molecule has no chromophore beyond the peptide backbone, ultraviolet detection is typically performed at a low wavelength, where baseline interference from solvents and buffers is a practical concern. Water content and counter-ion content are often reported alongside purity.
| 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.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
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.
== ABRF Executive Board == Kevin Knudtson, ABRF President, Genomics Division, University of Iowa Justine Kigenyi, Treasurer, KU Medical Center Marie Adams, Van Andel Institute Roxann Ashworth, Johns Hopkins University Kym Delventhal, Stowers Institute for Medical Research Sridar Chittur, SUNY Albany Nick Ambulos, University of Maryland School of Medicine Sue Weintraub, University of Texas Health Science Center at San Antonio Magnus Palmblad, Leiden University Medical Center Ken Schoppmann, ABRF Executive Director
==== Amino acid ==== Cortisol raises the free amino acids in the serum by inhibiting collagen formation, decreasing amino acid uptake by muscle, and inhibiting protein synthesis. Cortisol (as opticortinol) may inversely inhibit IgA precursor cells in the intestines of calves. Cortisol also inhibits IgA in serum, as it does IgM; however, it is not shown to inhibit IgE.
=== Literature === In Mary Shelley's novel Frankenstein (1818), Victor Frankenstein takes laudanum as his only means of sleeping and thus preserving his life while in recovery from months of fever and a series of horrible events. A laudanum-addicted character also appeared in Wilkie Collins' novel Armadale (1864–1866). Wilkie Collins' novel The Moonstone (1868) features laudanum "as an essential ingredient of the plot." Collins based his description of the drug's effects on his own experiences with it. Laudanum appears in Charles Baudelaire's prose poem The Double Room, published in his collection Le Spleen de Paris in 1869. Laudanum is portrayed as the surgical drug of choice for fifteenth-century physicians in Lawrence Schoonover's novel The Burnished Blade (1948), the plot of which deals in part with the smuggling of expensive raw opium into France from the Empire of Trebizond. Stephen Maturin, one of the main characters in Patrick O'Brian's Aubrey–Maturin series of novels (1969–2004) about the Napoleonic wars, is a sometime laudanum addict.
Sources: en.wikipedia.org
=== Chilled caramel topping === Another example of non-Newtonian fluid flow is chilled caramel ice cream topping (so long as it incorporates hydrocolloids such as carrageenan and gellan gum). The sudden application of force—by stabbing the surface with a finger, for example, or rapidly inverting the container holding it—causes the fluid to behave like a solid rather than a liquid. This is the "shear thickening" property of this non-Newtonian fluid. Gentler treatment, such as slowly inserting a spoon, will leave it in its liquid state. Trying to jerk the spoon back out again, however, will trigger the return of the temporary solid state.
Andrew Welsh has served as President of the board since September 2025, with Vice-President Anthony Di Pietro serving since March 2026. Essendon's board members are Andrew Welsh, Tim Roberts, David Wills, Dorothy Hisgrove, Andrew Muir, Kate O'Sullivan, Anthony Howard AM KC, and Catriona Larritt.
=== Hypodermis === Beneath these layers lies the hypodermis, which is composed of adipose tissue, fascia, as well as larger lymphatic and blood vessels. For joint and muscle disease treatment, topically applied drugs such as non-steroidal anti-inflammatory drugs (NSAIDs) can penetrate the subcutaneous tissue or even deeper tissues in the hypodermis. Drugs are primarily delivered into the underlying muscle by direct penetration without prior entry into the systemic circulation to prevent unintended side effects.
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。
Cool storage below freezing is usual for long-term retention, with a desiccant and protection from light. Portions are often split before first use to avoid repeated handling.