This is a working overview of 合成肽, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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 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.
| 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 |
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.
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.
Biologically, the peptide is studied mainly in the context of immune cell development and regulation. It is produced in the thymus and in several other tissues, and it appears to influence the maturation and activity of T cells and other immune populations. Laboratory work describes effects on cytokine production, on the balance between T cell subsets, and on the function of dendritic cells. Much of this evidence comes from cell culture and animal models, so the extent to which the same pathways operate in humans remains an open question.
Clinical interest has centered on chronic viral hepatitis, on immune restoration in various conditions, and on use as an adjuvant intended to improve responses to vaccines. Trials have reported mixed results, and regulatory status differs sharply between countries; in some places it is a prescription product, while elsewhere it is sold without an approved therapeutic indication. Because published studies vary widely in design, population, and endpoints, comparisons across them are difficult and no single conclusion covers the whole literature.
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。
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.
Clinical research has examined the peptide in chronic hepatitis B and C, as a vaccine adjuvant, and in sepsis and oncology settings. Results across trials have been mixed, and several studies were small or conducted under differing protocols. Regulatory status varies by country, and the compound is not approved in every jurisdiction where it is studied. Evidence for any single indication should be read with attention to sample size and endpoint choice.
There are also intra-country zones such as the Cactus Curtain surrounding the Guantanamo Bay Naval Base in Cuba, the Korean Demilitarised Zone along the North Korea-South Korea demarcation line and the Frontier Closed Area in Hong Kong. Important historical examples are the Wire of Death set up by the German Empire to control the Belgium–Netherlands border and the Iron Curtain, a set of border zones maintained by the Soviet Union and its satellite states along their borders with Western states. One of the most militarised parts was the restricted zone of the inner German border. While the zone was initially and officially for border security, it was eventually engineered to prevent escape from the Soviet sphere into the West. Ultimately, the Eastern Bloc governments resorted to using lethal countermeasures against those trying to cross the border, such as mined fences and orders to shoot anyone trying to cross into the West. The restrictions on building and habitation made the area a "green corridor", which today is known as the European Green Belt. In the area stretching inwards from its internal border with the mainland, Hong Kong maintains a Frontier Closed Area out of bounds to those without special authorisation. The area was established in the 1950s, when Hong Kong was under British administration, as a result of the Convention for the Extension of Hong Kong Territory before the transfer of sovereignty over Hong Kong in 1997. The area's purpose was to prevent illegal immigration and smuggling; smuggling had become prevalent as a consequence of the Korean War.
nucleosome-depleted region (NDR) A region of a genome or chromosome in which long segments of DNA are bound by few or no nucleosomes, and thus exposed to manipulation by other proteins and molecules, especially implying that the region is transcriptionally active.
Romania derives from the local name for Romanian (Romanian: român), which in turn derives from Latin romanus, meaning "Roman" or "of Rome". This ethnonym for Romanians is first attested in the sixteenth century by Italian humanists travelling in Transylvania, Moldavia, and Wallachia. The oldest known surviving document written in Romanian that can be precisely dated, a 1521 letter known as the "Letter of Neacșu from Câmpulung", is notable for including the first documented occurrence of Romanian in a country name: Wallachia is mentioned as Țara Rumânească.
==== Protein C and Protein S ==== Protein C is a major physiological anticoagulant. It is a vitamin K-dependent serine protease enzyme that is activated by thrombin into activated protein C (APC). Protein C is activated in a sequence that starts with Protein C and thrombin binding to a cell surface protein thrombomodulin. Thrombomodulin binds these proteins in such a way that it activates Protein C. The activated form, along with protein S and a phospholipid as cofactors, degrades FVa and FVIIIa. Quantitative or qualitative deficiency of either (protein C or protein S) may lead to thrombophilia (a tendency to develop thrombosis). Impaired action of Protein C (activated Protein C resistance), for example by having the "Leiden" variant of Factor V or high levels of FVIII, also may lead to a thrombotic tendency.
Sources: en.wikipedia.org
Ionic flow in action potentials at Blackwell Publishing Action potential propagation in myelinated and unmyelinated axons at Blackwell Publishing Generation of AP in cardiac cells and generation of AP in neuron cells Resting membrane potential from Life: The Science of Biology, by WK Purves, D Sadava, GH Orians, and HC Heller, 8th edition, New York: WH Freeman, ISBN 978-0-7167-7671-0. Ionic motion and the Goldman voltage for arbitrary ionic concentrations at The University of Arizona A cartoon illustrating the action potential Action potential propagation Open-source software to simulate neuronal and cardiac action potentials at SourceForge.net Introduction to the Action Potential, Neuroscience Online (electronic neuroscience textbook by UT Houston Medical School) Khan Academy: Electrotonic and action potential Archived 2 July 2014 at the Wayback Machine
=== First nucleotide recognition === The NIKS site is responsible for binding with the first nucleotide of the stop codon: uracil. This is achieved by the Asn61 and Lys63 residues of NIKS forming hydrogen bonds with the carbonyl group of the uracil. A secondary hydrogen bond is formed between the Asn61 residue with a different carbonyl found on uracil. Additionally it has been hypothesized that the lys63 residue interacts with the backbone of the mRNA which contributes to stability and proper alignment of eRF1. The specificity of the mechanism for uracil means that any other nucleotide (guanine, adenosine, thymine, cytosine) will produce a structure that doesn't have extensive hydrogen bonding to stabilize the docking of eRF1.
Tofisopam has also appeared in Washington State’s equine drug regulations. Washington State regulatory documents list ‘’‘Grandaxain’’’ and ‘’‘Seriel’’’ and as a Class 2 substance within equine medicine. Tofisopam has been shown to act as an inhibitor of the liver enzyme CYP3A4, and some researches suspect that this could cause dangerous drug interactions with other medications metabolised by this enzyme, although the clinical significance of these findings remains unclear.
qPCR is very sensitive (detection of a single mRNA molecule is theoretically possible), but can be expensive depending on the type of reporter used; fluorescently labeled oligonucleotide probes are more expensive than non-specific intercalating fluorescent dyes. For expression profiling, or high-throughput analysis of many genes within a sample, quantitative PCR may be performed for hundreds of genes simultaneously in the case of low-density arrays. A second approach is the hybridization microarray. A single array or "chip" may contain probes to determine transcript levels for every known gene in the genome of one or more organisms. Alternatively, "tag based" technologies like Serial analysis of gene expression (SAGE) and RNA-Seq, which can provide a relative measure of the cellular concentration of different mRNAs, can be used. An advantage of tag-based methods is the "open architecture", allowing for the exact measurement of any transcript, with a known or unknown sequence. Next-generation sequencing (NGS) such as RNA-Seq is another approach, producing vast quantities of sequence data that can be matched to a reference genome. Although NGS is comparatively time-consuming, expensive, and resource-intensive, it can identify single-nucleotide polymorphisms, splice-variants, and novel genes, and can also be used to profile expression in organisms for which little or no sequence information is available.
A glycome is the entire complement or complete set of all sugars, whether free or chemically bound in more complex molecules, of an organism. An alternative definition is the entirety of carbohydrates in a cell. The glycome may in fact be one of the most complex entities in nature. "Glycomics, analogous to genomics and proteomics, is the systematic study of all glycan structures of a given cell type or organism" and is a subset of glycobiology. "Carbohydrate", "glycan", "saccharide", and "sugar" are generic terms used interchangeably in this context and includes monosaccharides, oligosaccharides, polysaccharides, and derivatives of these compounds. Carbohydrates consist of "hydrated carbon", i.e. [CH2O]n. Monosaccharides are a carbohydrate that cannot be hydrolyzed into a simpler carbohydrate and are the building blocks of oligosaccharides and polysaccharides. Oligosaccharides are linear or branched chains of monosaccharides attached to one another via glycosidic linkages. The number of monosaccharide units can vary. Polysaccharides are glycans composed of repeating monosaccharides, generally greater than ten monosaccharide units in length. The glycome exceeds the complexity of the proteome as a result of the even greater diversity of the glycome's constituent carbohydrates and is further complicated by the sheer multiplicity of possibilities in the combination and interaction of the carbohydrates with each other and with proteins. "The spectrum of all glycan structures — the glycome — is immense.
Sources: en.wikipedia.org
== History == One of the earliest accounts of the tetrahedral intermediate came from Rainer Ludwig Claisen in 1887. In the reaction of benzyl benzoate with sodium methoxide, and methyl benzoate with sodium benzyloxide, he observed a white precipitate which under acidic conditions yields benzyl benzoate, methyl benzoate, methanol, and benzyl alcohol. He named the likely common intermediate “additionelle Verbindung.”
{\displaystyle {\begin{aligned}z:\ &\rho \left({\partial _{t}u_{z}}+u_{r}{\partial _{r}u_{z}}+{\frac {u_{\varphi }}{r}}{\partial _{\varphi }u_{z}}+u_{z}{\partial _{z}u_{z}}\right)\\&\quad =-{\partial _{z}p}\\&\qquad +\mu \left({\frac {1}{r}}\partial _{r}\left(r{\partial _{r}u_{z}}\right)+{\frac {1}{r^{2}}}{\partial _{\varphi }^{2}u_{z}}+{\partial _{z}^{2}u_{z}}\right)\\&\qquad +{\frac {1}{3}}\mu \partial _{z}\left({\frac {1}{r}}{\partial _{r}\left(ru_{r}\right)}+{\frac {1}{r}}{\partial _{\varphi }u_{\varphi }}+{\partial _{z}u_{z}}\right)\\&\qquad +\rho g_{z}.\end{aligned}}}
=== New Zealand === The opposition Green Party of Aotearoa New Zealand's co-leader, Marama Davidson, stated "this is a unilateral attack that goes against any enduring pathway to international peace through justice." She called upon Prime Minister Christopher Luxon to condemn the United States for attacking Venezuela.
=== Chemoresistance === In some cases, the characteristics of CAF provide therapeutic resistance. Soluble factor resistance occurs when CAF either directly secrete signals (cytokines or growth factors) or influence the cells around them to give off similar signals, which reduce the efficacy of therapeutic drugs. For instance, this can either be done by an increased secretion of antiapoptotic factors or by altering the cell environment (e.g. pH) to counteract the actions of the drug. Another form is cell adhesion- mediated drug resistance. This involves the tight attachment of neoplastic cells to the extracellular matrix or stromal cells. For example, secretion of TGF-beta allows cancerous cells to bind more successfully to the extracellular matrix thus evading the action of some cancer drugs.
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.
It is a chain of 28 amino acids, with an acetyl group attached to the first serine residue. The synthetic version replicates this sequence. Its molecular mass is about 3,108 daltons.