prothymosin alpha comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-27. Numbers and descriptions here follow the published literature rather than marketing material.
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。
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.
| 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 |
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.
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.
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.
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.
=== Prescription drug history === Antibiotics first arrived on the medical scene in 1932 thanks to Gerhard Domagk; and were coined the "wonder drugs". The introduction of the sulfa drugs led to the mortality rate from pneumonia in the U.S. to drop from 0.2% each year to 0.05% (i.e., 1⁄4 as much) by 1939. Antibiotics inhibit the growth or the metabolic activities of bacteria and other microorganisms by a chemical substance of microbial origin. Penicillin, introduced a few years later, provided a broader spectrum of activity compared to sulfa drugs and reduced side effects. Streptomycin, found in 1942, proved to be the first drug effective against the cause of tuberculosis and also came to be the best known of a long series of important antibiotics. A second generation of antibiotics was introduced in the 1940s: aureomycin and chloramphenicol. Aureomycin was the best known of the second generation. Lithium was discovered in the 19th century for nervous disorders and its possible mood-stabilizing or prophylactic effect; it was cheap and easily produced. As lithium fell out of favor in France, valpromide came into play. This antibiotic was the origin of the drug that eventually created the mood stabilizer category. Valpromide had distinct psychotrophic effects that were of benefit in both the treatment of acute manic states and in the maintenance treatment of manic depression illness. Psychotropics can either be sedative or stimulant; sedatives aim at damping down the extremes of behavior. Stimulants aim at restoring normality by increasing tone.
TFA is the precursor to trifluoroacetic anhydride, trifluoroperacetic acid, and 2,2,2-trifluoroethanol. It is a reagent used in organic synthesis because of a combination of convenient properties: volatility, solubility in organic solvents, and its strength as an acid. TFA is also less oxidizing than sulfuric acid but more readily available in anhydrous form than many other acids. One complication to its use is that TFA forms an azeotrope with water (b. p. 105 °C). TFA is used as a strong acid to remove protecting groups such as Boc used in organic chemistry and peptide synthesis. At a low concentration, TFA is used as an ion pairing agent in liquid chromatography (HPLC) of organic compounds, particularly peptides and small proteins. TFA is a versatile solvent for NMR spectroscopy (for materials stable in acid). It is also used as a calibrant in mass spectrometry. TFA is used to produce trifluoroacetate salts. TFA is a high-production chemical and has wide applicationos in organic synthesis, e.g., in rearrangements, functional group deprotections, oxidations, reductions, condensations, hydroarylations, and trifluoromethylations.
=== Internal systems === Bats have an efficient circulatory system. They seem to make use of particularly strong venomotion, a rhythmic contraction of venous wall muscles. In most mammals, the walls of the veins provide mainly passive resistance, maintaining their shape as deoxygenated blood flows through them, but in bats, they appear to actively support blood flow back to the heart with this pumping action. Because of their small, lightweight bodies, bats are not at risk of blood rushing to their heads when roosting. Compared to a terrestrial mammal of similar size, the bat's heart can be up to three times larger and pump more blood, while blood oxygen levels are twice as much. An active microbat can reach a heart rate of 1000 beats per minute.
== Chemistry == Vortioxetine (1-[2-(2,4-dimethylphenylsulfanyl)phenyl]piperazine) is a bis-aryl-sulfanyl amine as well as piperazine derivative. The acid dissociation constant (pKa) values for vortioxetine hydrobromide were determined to be 9.1 (± 0.1) and 3.0 (± 0.2) according to an Australian Public Assessment Report.
Sources: en.wikipedia.org
==== Reactions of cysteines ==== Because free cysteine rarely occurs on protein surface, it is an excellent choice for chemoselective modification. Under basic condition, the cysteine residues will be deprotonated to generate a thiolate nucleophile, which will react with soft electrophiles, such as maleimides and iodoacetamides (shown in the first two reactions in Figure 2 below). As a result, a carbon-sulfur bond is formed. Another modification of cysteine residues involves the formation of disulfide bond (shown in the third reaction in Figure 2). The reduced cysteine residues react with exogenous disulfides, generating new a disulfide bond on the protein. An excess of disulfides is often used to drive the reaction, such as 2-thiopyridone and 3-carboxy-4-nitrothiophenol. Electron-deficient alkynes were demonstrated to selectively react with cysteine residues of proteins in the presence of other nucleophilic amino acid residues. Depending on the alkyne substitution, these reactions can produce either cleavable (when alkynone derivatives are used), or hydrolytically stable bioconjugates (when 3-arylpropiolonitriles are used; the last reaction below in Figure 2).
On Stalin's instructions on 5 January 1946, Kimon Georgiev, Damyan Velchev and Anton Yugov met with opposition leaders Nikola Petkov and Kosta Lulchev, but they flatly refused to enter the government, rejecting the legitimacy of the elections and demanding an end to the Communists' terror. On 7 January Georgiev was summoned to Stalin, who sharply criticised him for his soft attitude towards the opposition. On 10 January, Soviet First Deputy Foreign Minister Andrei Vyshinsky met with Petkov and Lulchev in Sofia, but they did not change their position.
== Biological roles == Human uses of AGPs include the use of gum arabic in the food and pharmaceutical industries because of natural properties in thickening and emulsification. AGPs in cereal grains have potential applications in biofortification, as sources of dietary fibre to support gut bacteria and protective agents against ethanol toxicity. AGPs are found in a wide range of plant tissues, in secretions of cell culture medium of root, leaf, endosperm and embryo tissues, and some exudate producing cell types such as stylar canal cells. AGPs have been shown to regulate many aspects of plant growth and development including male-female recognition in reproduction organs, cell division and differentiation in embryo and post-embryo development, seed mucilage cell wall development, root salt tolerance and root-microbe interactions. These studies suggest that they are multifunctional, similar to what is found in mammalian proteoglycans/glycoproteins. Conventional methods to study functions of AGPs include the use of β-glycosyl (usually glucosyl) Yariv reagents and monoclonal antibodies (mAbs). β-Glycosyl Yariv reagents are synthetic phenylazo glycoside probes that specifically, but not covalently, bind to AGPs and can be used to precipitate AGPs from solution. They are also used commonly as histochemical stains to probe the locations and distribution of AGPs. A number of studies have shown that addition of β-Yariv reagents to plant growth medium can inhibit seedling growth, cell elongation, block somatic embryogenesis and fresh cell wall mass accumulation.
In August 1914 Britain entered the First World War. Tolkien's relatives were shocked when he elected not to volunteer immediately for the British Army. In a 1941 letter to his son Michael, Tolkien recalled: "In those days chaps joined up, or were scorned publicly. It was a nasty cleft to be in for a young man with too much imagination and little physical courage." Instead, Tolkien, "endured the obloquy", and entered a programme by which he delayed enlistment until completing his degree. By the time he passed his finals in July 1915, Tolkien recalled that the hints were "becoming outspoken from relatives". He was commissioned as a temporary second lieutenant in the Lancashire Fusiliers on 15 July 1915. He trained with the 13th (Reserve) Battalion on Cannock Chase, Rugeley Camp near to Rugeley, Staffordshire, for eleven months. In a letter to Edith, Tolkien complained: "Gentlemen are rare among the superiors, and even human beings rare indeed." Following their wedding Lieutenant and Mrs. Tolkien took up lodgings near the training camp. On 2 June 1916, Tolkien received a telegram summoning him to Folkestone for posting to France. The Tolkiens spent the night before his departure in a room at the Plough & Harrow Hotel in Edgbaston, Birmingham. He later wrote: "Junior officers were being killed off, a dozen a minute. Parting from my wife then ... it was like a death."
Cossack forces played an important role in Russia's wars of the 18th–20th centuries, including the Great Northern War, the Seven Years' War, the Crimean War, the Napoleonic Wars, the Caucasus War, many Russo-Persian Wars, many Russo-Turkish Wars, and the First World War. In the late 19th and early 20th centuries, the Tsarist regime used Cossacks extensively to perform police service. Cossacks also served as border guards on national and internal ethnic borders, as had been the case in the Caucasus War. During the Russian Civil War, Don and Kuban Cossacks were the first people to declare open war against the Bolsheviks. In 1918, Russian Cossacks declared their complete independence, creating two independent states, the Don Republic and the Kuban People's Republic, and the revived Hetmanate emerged in Ukraine. Cossack troops formed the effective core of the anti-Bolshevik White Army, and Cossack republics became centers for the anti-Bolshevik White movement. With the victory of the Red Army, Cossack lands were subjected to decossackization and the Holodomor famine. As a result, during the Second World War, their loyalties were divided and both sides had Cossacks fighting in their ranks. Following the dissolution of the Soviet Union, the Cossacks made a systematic return to Russia. Many took an active part in post-Soviet conflicts. In the 2002 Russian Census, 140,028 people reported their ethnicity as Cossack. There are Cossack organizations in Russia, Kazakhstan, Ukraine, Belarus, and the United States.
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.