solid-phase synthesis is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-07-02. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
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.
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.
Thymosin alpha 1 is approved as a medicine in several countries, including Italy and China, for indications such as chronic hepatitis B and as an immune adjuvant. It is not approved by the United States Food and Drug Administration as a therapeutic product. In research settings the peptide appears in studies of sepsis, vaccine response, and oncology support, often with mixed or inconclusive results. The evidence base is uneven, and reviews note that many trials were small. Regulatory status therefore differs widely between jurisdictions.
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.
== RNA structural alignment == Structural alignment techniques have traditionally been applied exclusively to proteins, as the primary biological macromolecules that assume characteristic three-dimensional structures. However, large RNA molecules also form characteristic tertiary structures, which are mediated primarily by hydrogen bonds formed between base pairs as well as base stacking. Functionally similar noncoding RNA molecules can be especially difficult to extract from genomics data because structure is more strongly conserved than sequence in RNA as well as in proteins, and the more limited alphabet of RNA decreases the information content of any given nucleotide at any given position. However, because of the increasing interest in RNA structures and because of the growth of the number of experimentally determined 3D RNA structures, few RNA structure similarity methods have been developed recently. One of those methods is, e.g., SETTER which decomposes each RNA structure into smaller parts called general secondary structure units (GSSUs). GSSUs are subsequently aligned and these partial alignments are merged into the final RNA structure alignment and scored. The method has been implemented into the SETTER webserver. A recent method for pairwise structural alignment of RNA sequences with low sequence identity has been published and implemented in the program FOLDALIGN.
In chemical ionization (CI) a reagent gas, typically methane or ammonia is introduced into the mass spectrometer. Depending on the technique (positive CI or negative CI) chosen, this reagent gas will interact with the electrons and analyte and cause a 'soft' ionization of the molecule of interest. A softer ionization fragments the molecule to a lower degree than the hard ionization of EI. One of the main benefits of using chemical ionization is that a mass fragment closely corresponding to the molecular weight of the analyte of interest is produced. In positive chemical ionization (PCI) the reagent gas interacts with the target molecule, most often with a proton exchange. This produces the species in relatively high amounts. In negative chemical ionization (NCI) the reagent gas decreases the impact of the free electrons on the target analyte. This decreased energy typically leaves the fragment in great supply.
FutureFeed is a ruminant livestock feed ingredient based on seaweed that can reduce methane emissions, established by Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO). FutureFeed holds the global intellectual property to use the seaweed Asparagopsis for livestock feed. Lowered methane emissions can be achieved by the addition of a small amount of the seaweed into the daily diet of livestock. This discovery was made by a team of scientists from CSIRO and James Cook University (JCU), supported by Meat & Livestock Australia (MLA), who came together in 2013 to investigate the methane reduction potential of various native Australian seaweeds. Asparagopsis is a genus of red algae, endemic in many parts of the world including Australia. The seaweed has proven to be the most efficient natural supplement available for lowering methane from ruminant livestock. It also has feed efficiency benefits. The active ingredient in seaweed is bromoform, which inhibits a key enzyme for methanogenesis.
=== Atomic number === In chemistry, the number of protons in the nucleus of an atom is known as the atomic number, which determines the chemical element to which the atom belongs. For example, the atomic number of chlorine is 17; this means that each chlorine atom has 17 protons and that all atoms with 17 protons are chlorine atoms. The chemical properties of each atom are determined by the number of (negatively charged) electrons, which for neutral atoms is equal to the number of (positive) protons so that the total charge is zero. For example, a neutral chlorine atom has 17 protons and 17 electrons, whereas a Cl− anion has 17 protons and 18 electrons for a total charge of −1 e. All atoms of a given element are not necessarily identical, however. The number of neutrons may vary to form different isotopes, and energy levels may differ, resulting in different nuclear isomers. For example, there are two stable isotopes of chlorine: 3517Cl with 35 − 17 = 18 neutrons and 3717Cl with 37 − 17 = 20 neutrons.
Sources: en.wikipedia.org
Bukele announced at the Bitcoin 2021 conference on 5 June 2021 that he would introduce a bill to the Legislative Assembly that would make bitcoin legal tender, saying that it would "generate jobs" and promote "financial inclusion" in the short term. The Legislative Assembly approved the bill three days later. Although the World Bank rejected a request from the Salvadoran government to assist it with the implementation of bitcoin as legal tender, citing concerns about transparency and the environmental effects of bitcoin mining, Athena Bitcoin announced that it would invest $1 million to install 1,500 bitcoin ATMs. This would allow users to exchange U.S. dollars for bitcoin and vice versa. Bitcoin became legal tender on 7 September 2021 in El Salvador, the first country to do so. It became legal tender alongside the United States dollar, which had been adopted in 2001 and replaced the Salvadoran colón. About 1,000 people marched in the streets of San Salvador to protest the country's adoption of bitcoin, though other citizens saw the adoption as an "opportunity." According to The New York Times, bitcoin adoption has allowed Salvadorans without bank accounts to "access digital payments, invest savings or boost earnings." The day before bitcoin became legal tender, Bukele announced that the Salvadoran government had bought its first 200 bitcoins. Economist Steve Hanke stated that El Salvador had "the most distressed sovereign debt in the world" due to its adoption of bitcoin, and other economists predicted that the country would likely default on its debt.
September 13 Trump dismisses concerns over the rapid pace of AI research, following days of warnings from experts in the field about possible existential risks. In a meeting with US officials, the Houthis promise not to attack American or any other commercial vessels, with the exception of those belonging to Saudi Arabia. September 14 The yield on benchmark 10-year U.S. Treasury notes rises above 5% for the first time since October 2023, amid a global bond sell-off as surging oil prices and disruption to Middle Eastern energy supplies fuel renewed fears of inflation. The yield reaches 5.01%, while Brent crude rises above $108 a barrel. U.S. Senator Mitch McConnell returns to the Senate floor following a three-month absence. Trump announces that he is willing to engage with Iran to negotiate a deal. Donald Trump Jr.'s wedding celebration is reported to have been partly funded by a Russian oligarch with close connections to President Vladimir Putin. A court in Boston blocks Trump restrictions on how long foreign students and journalists can remain in the country. The Supreme Court rejects the Trump administration's request to lift an injunction blocking new United States Postal Service restrictions on mail-in voting ahead of the midterm elections. The US Space Force announces that the country now has weapons deployed in orbit, suggesting that the unspecified platforms are needed to compete with adversaries China and Russia.
Most modern nuclear weapons utilize 238U as a "tamper" material (see nuclear weapon design). A tamper which surrounds a fissile core works to reflect neutrons and to add inertia to the compression of the 239Pu charge. As such, it increases the efficiency of the weapon and reduces the critical mass required. In the case of a thermonuclear weapon, 238U can be used to encase the fusion fuel, the high flux of very energetic neutrons from the resulting fusion reaction causes 238U nuclei to split and adds more energy to the "yield" of the weapon. Such weapons are referred to as fission-fusion-fission weapons after the order in which each reaction takes place. An example of such a weapon is Castle Bravo. The larger portion of the total explosive yield in this design comes from the final fission stage fueled by 238U, producing enormous amounts of radioactive fission products. For example, an estimated 77% of the 10.4-megaton yield of the Ivy Mike thermonuclear test in 1952 came from fast fission of the depleted uranium tamper. Because depleted (or natural) uranium has no critical mass, it can be added to thermonuclear bombs in almost unlimited quantity. The Soviet Union's test of the Tsar Bomba in 1961 produced "only" 50 megatons of explosive power, over 90% of which came from fusion because the 238U final stage had been replaced with lead. Had 238U been used instead, the yield of the Tsar Bomba could have been well above 100 megatons, and it would have produced nuclear fallout equivalent to one third of the global total that had been produced up to that time.
== Mechanism of action == GLP-1 poly-agonist peptides work by activating two hormone receptors rather than one. The two receptors targeted are both triggered naturally after eating, but they act on different parts of the body and play complementary roles in regulating blood sugar, appetite, and fat metabolism. In the pancreas, both receptors stimulate insulin release in response to elevated blood glucose, but through slightly different cellular pathways. Activating both at once produces a stronger insulin response than either receptor alone. The two receptors also balance each other in their effects on glucagon; GIP raises glucagon when blood sugar is too low, while GLP-1 suppresses glucagon when blood sugar is too high. In fat tissue, GIP promotes the removal of triglycerides from the bloodstream, while GLP-1 encourages fat breakdown through signals sent via the central nervous system. Both hormones also reduce fat build up in the liver and lower insulin resistance.
=== Controversy === In 2015, ex-Transportation corps commander Major General Liu Zhanqi, ex-Transportation corps Political commissar Major General Wang Xin and ex-Transportation Corps Chief engineer Major General Miao Guirong were arrested on 16 June, 31 July and 15 September respectively on corruption-related charges as part of the anti-corruption campaign under Xi Jinping. As of 16 September 2015, a total of 43 people were arrested in relation to the case.
Sources: en.wikipedia.org
It corresponds to a fragment of the larger protein prothymosin alpha, which is present in many tissues. The isolated 28-amino-acid peptide was originally obtained from thymus preparations, and the pharmaceutical product is synthesized rather than extracted. The term therefore describes both a natural fragment and a manufactured drug substance.
Thymosin alpha-1 is a single defined 28-residue peptide, while the broader family includes unrelated peptides such as thymosin beta-4. The shared name reflects historical isolation from thymus tissue rather than a common structure. Confusion between the two is common in older literature.
No single pathway fully accounts for its reported effects. Several studies describe interaction with innate immune receptors and downstream cytokine changes, but the complete picture is not settled. Open questions remain about which effects occur at physiological concentrations.
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。