If you have been reading about 合成肽 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 2026-07-15. Where a claim depends on a specific study, the study is described rather than over-claimed.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
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 |
|---|---|---|
| Class | Synthetic peptide | 28 residues; not a small-molecule compound |
| Molecular mass | About 3,106 Da | Monoisotopic mass of the unmodified chain |
| N-terminal group | Acetylated serine | Present in both native and synthetic forms |
| Secondary structure | Disulfide-constrained loop | One bridge between two cysteine residues |
| Typical source | Solid-phase synthesis | Early isolates came from bovine thymus extracts |
Thymosin alpha 1 was identified in 1977 as a component of thymosin fraction 5, a heterogeneous preparation used in early studies of thymic function. Investigators purified the active material and determined its amino acid sequence, which enabled chemical synthesis. Work in the following decades concentrated on T-cell maturation and immune reconstitution in animals and small human cohorts. Early preparations varied in composition, so results from that period are difficult to compare with studies using defined synthetic peptide.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Findings across trials are mixed; some report changes in selected immune markers, while others find no clear clinical benefit. Many studies are small and define outcomes differently, which limits comparison. Regulatory approval is confined to a few countries, and the compound is not an approved drug in the United States or most of Europe.
Overall evidence quality varies considerably. A large share of published reports come from single centers, rely on surrogate immunological markers, or lack adequate control groups. Systematic reviews have highlighted this heterogeneity as a barrier to pooling results. Open questions include which patients, if any, might benefit, what treatment duration is appropriate, and whether any effect is independent of standard care. The peptide is often described as an immune modulator rather than a therapy for one disease, which complicates confirmatory trial design.
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 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.
The majority of mammals have seven cervical vertebrae (bones in the neck). The exceptions are the manatee and the two-toed sloth, which have six, and the three-toed sloth which has nine. All mammalian brains possess a neocortex, a brain region unique to mammals. Placental brains have a corpus callosum, unlike monotremes and marsupials.
== Formation and secretion == Osteoid is synthesized and secreted by osteoblasts, specialized bone-forming cells. Osteoblasts are large cuboidal cells characterized by abundant rough endoplasmic reticulum, reflecting their high synthetic activity. At their apical surface, osteoblasts secrete large amounts of type I collagen and smaller amounts of matrix organizing proteins, including osteocalcin and osteopontin. The newly secreted osteoid forms a hydrated protein matrix layer between the mineralization front and the osteoblast layer. The synthesis of bone matrix occurs in two main steps: deposition of organic matrix (osteoid) and its subsequent mineralization. During active bone formation, osteoblasts continuously produce osteoid matrix until mineralization occurs.
The number of 60Fe atoms per unit area found on Earth can be estimated if the typical amount of 60Fe ejected from a supernova is known. This can be done by dividing the surface mass density (Σej) by the atomic mass of 60Fe.
Sources: en.wikipedia.org
== Occurrence == Diallyl disulfide and the related trisulfide are produced by decomposition of allicin, which is released upon breaking the cells of the Alliaceae plants, especially garlic. The diallyl disulfide yield is the highest for the steam distillation of garlic bulbs which contain about 2 wt.% of diallyl disulfide-rich oil. Diallyl disulfide can also be extracted from garlic leaves, but their oil content is significantly lower at 0.06 wt.%.
=== Evo Morales declared persona non grata === On 20 August 2021, Congress voted against a proposal to declare the former Bolivian president Evo Morales a persona non grata. However, on 22 November 2021, the Foreign Relations Commission of Congress, led by Popular Force, agreed to declare Evo Morales a persona non grata for "his negative political activism" and "political interference" in Peruvian territory, referring to repeated trips Morales undertook to rally support for Castillo's agenda. The Foreign Relations Commission (FRC) also questioned Morales' protection by state security and use of official vehicles. The FRC's resolution urged authorities to take "necessary actions" to prohibit Morales from entering Peru. The Free Peru parliamentarian Margot Palacios spoke out against the FRC's resolution, saying that "Only a colonial mentality, narrow, premodern, medieval and discriminatory, can deny entry to Peru to a brother who has done much for the Andean culture, of which Peruvians and Bolivians are part of. For several centuries, we were one state: the Tahuantinsuyo."
Electromagnetic spectrum refers to the full range of all frequencies of electromagnetic radiation and also to the characteristic distribution of electromagnetic radiation emitted or absorbed by that particular object. Devices used to measure an electromagnetic spectrum are called spectrograph or spectrometer. The visible spectrum is the part of the electromagnetic spectrum that can be seen by the human eye. The wavelength of visible light ranges from 390 to 700 nm. The absorption spectrum of a chemical element or chemical compound is the spectrum of frequencies or wavelengths of incident radiation that are absorbed by the compound due to electron transitions from a lower to a higher energy state. The emission spectrum refers to the spectrum of radiation emitted by the compound due to electron transitions from a higher to a lower energy state. Light from many different sources contains various colors, each with its own brightness or intensity. A rainbow, or prism, sends these component colors in different directions, making them individually visible at different angles. A graph of the intensity plotted against the frequency (showing the brightness of each color) is the frequency spectrum of the light. When all the visible frequencies are present equally, the perceived color of the light is white, and the spectrum is a flat line. Therefore, flat-line spectra in general are often referred to as white, whether they represent light or another type of wave phenomenon (sound, for example, or vibration in a structure).
Sources: en.wikipedia.org
The Coffee Bean & Tea Leaf (sometimes shortened to simply "Coffee Bean" or "The Coffee Bean") is an American coffee chain founded in 1963. It was previously owned and operated by International Coffee & Tea, LLC based in Los Angeles, California, before it was acquired in 2019 by Jollibee Group, a multinational company based in the Philippines, for $350 million. As of 2024, the chain has 1,232 stores spread across 24 countries.
=== Systems biology and systems medicine === Beginning in the 1990s, Hood focused more on cross-disciplinary biology and systems biology. He established in 1992 the first cross-disciplinary biology department, the Molecular Biotechnology Department at the University of Washington. In 2000, he co-founded the Institute for Systems Biology (ISB) in Seattle, Washington to develop strategies and technologies for systems approaches to biology and medicine. He co-led the Hood-Price research lab at ISB with Nathan Price until Price left to join Center for Human Healthspan at the Buck Institute for Research on Aging. Hood pioneered the systems biology concept of considering human biology as a "network of networks." In this model, understanding how systems function requires knowledge of: (1) the components of each network (including genetic, molecular, cellular, organ networks), (2) how these networks inter- and intra-connect, (3) how the networks change over time and undergo perturbations, and (4) how function is achieved within these networks. At the ISB under Hood's direction, genomic, transcriptomic, metabolomic and proteomic technologies are used to understand the "network of networks" and are focused on diverse biological systems (e.g. yeast, mice and humans). Hood applies the notion of systems biology to the study of medicine, specifically to cancer and neurodegenerative disease.
==== Nitriles from glucosinolates in cruciferous plants ==== An important group of natural products that serve as precursors of nitriles are the mustard oil glycosides (glucosinolates), which are biosynthesized analogously to direct nitrile formation via an aldoxime intermediate. Glucosinolates constitute a major class of secondary metabolites produced by plants of the cruciferous family (Brassicaceae) for defense against herbivores and microorganisms. Normally, glucosinolates are hydrolyzed by myrosinase to isothiocyanates; however, in the presence of an additional protein (epithio specifier protein), nitriles are formed instead. Sinigrin is found primarily in horseradish, wasabi, and brown mustard, but also in head cabbage, kale, cauliflower, and Brussels sprouts; in addition to allyl isothiocyanate, it can be degraded to allyl cyanide (3-butenenitrile). Glucotropaeolin, present in garden cress, is degraded to phenylacetonitrile; gluconasturtiin, found in watercress, is degraded to 3-phenylpropionitrile. Sinalbin, occurring in Lepidium draba, can analogously be degraded to 4-hydroxyphenylacetonitrile.
Sources: en.wikipedia.org
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.
The single bridge between two cysteine residues holds the chain in a folded loop that influences its shape and its behavior in solution. Loss of the bridge through reduction or oxidation shifts chromatographic retention and is tracked during stability work.
It is a defined 28-residue sequence derived from a larger precursor, whereas many other thymic preparations are mixtures of several polypeptides. Its acetylated amino terminus and single disulfide bridge distinguish it chemically from unrelated thymic extracts.
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.