The short version of solid-phase synthesis fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-13. Anything still debated is marked as such rather than presented as settled.
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.
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。
| 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.
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.
Protein primary structure is the linear sequence of amino acids in a peptide or protein. By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthesis is most commonly performed by ribosomes in cells. Peptides can also be synthesized in the laboratory. Protein primary structures can be directly sequenced, or inferred from DNA sequences.
=== In popular culture === U-47700 is the title of a 2021 Dutch sci-fi short film by director Erasmo de la Parra. In the film, the characters are addicted to a new drug containing the substance U-47700.
Over the November 2016 Thanksgiving holiday weekend, President-Elect Donald Trump tweeted that he was in talks with Carrier Management to keep the factory in Indiana and not move to Mexico. On November 30, 2016, Carrier announced that it had negotiated an agreement with President-elect Trump and Vice President-elect Mike Pence to continue manufacturing gas furnaces in Indianapolis, in addition to retaining engineering and headquarters staff, preserving more than 1,000 jobs in Indianapolis. The agreement included a state incentive package of about $7 million over 10 years. The number of jobs saved was later revised down to 800. In May 2017, as part of their previously announced plan, Carrier told the state of Indiana that it will cut 632 jobs from its Indianapolis factory. Layoffs began at the end of July 2017, with each worker receiving one week's salary for each year of employment, education and job training, plus 6 months of health insurance as part of the severance package. The New York Times reported on August 10, 2018, that Carrier's Indianapolis furnace plant was plagued by low morale and absenteeism because "employees share a looming sense that a factory shutdown is inevitable — that Carrier has merely postponed the closing until a more politically opportune moment." On November 26, 2018, United Technologies announced that it would spin off UTC Climate, Controls & Security as an independent company known as Carrier Global Corporation. In April 2020, United Technologies announced that the separation and spin-off of Carrier had been completed.
=== Airspheres === These are vast, brown dwarf-sized bubbles of atmosphere enclosed by force fields, and (presumably) set up by an ancient advanced race at least one and a half billion years ago (see: Look to Windward). There is only minimal gravity within an airsphere. They are illuminated by moon-sized orbiting planetoids that emit enormous light beams. Citizens of the Culture live there only very occasionally as guests, usually to study the complex ecosystem of the airspheres and the dominant life-forms: the "dirigible behemothaurs" and "gigalithine lenticular entities", which may be described as inscrutable, ancient intelligences looking similar to a cross between gigantic blimps and whales. The airspheres slowly migrate around the galaxy, taking anywhere from 50 to 100 million years to complete one circuit. In the novels no one knows who created the airspheres or why, but it is presumed that whoever did has long since sublimed but may maintain some obscure link with the behemothaurs and lenticular entities. Guests in the airspheres are not allowed to use any force-field technology, though no reason has been offered for this prohibition. The airspheres resemble in some respects the orbit-sized ring of breathable atmosphere created by Larry Niven in The Integral Trees, but spherical not toroidal, require a force field to retain their integrity, and arose by artificial rather than natural processes.
Sources: en.wikipedia.org
== Further reading == Habibi, N; Kamaly, N; Memic, A; Shafiee, H (2016). "Self-assembled peptide-based nanostructures: Smart nanomaterials toward targeted drug delivery". Nano Today. 11 (1): 41–60. doi:10.1016/j.nantod.2016.02.004. PMC 4834907. PMID 27103939.
In a small clinical trial in eighteen pediatric subjects with intractable weight gain following therapy for acute lymphoblastic leukemia or brain tumors and other evidence of hypothalamic dysfunction, octreotide reduced body mass index (BMI) and insulin response during glucose tolerance test, while increasing parent-reported physical activity and quality of life (QoL) relative to placebo. In a separate placebo-controlled trial of obese adults without known hypothalamic lesions, obese subjects who received long-acting octreotide lost weight and reduced their BMI compared to subjects receiving placebo; post hoc analysis suggested greater effects in participants receiving the higher dose of the medication, and among "Caucasian subjects having insulin secretion greater than the median of the cohort." "There were no statistically significant changes in QoL scores, body fat, leptin concentration, Beck Depression Inventory, or macronutrient intake", although subjects taking octreotide had higher blood glucose after a glucose tolerance test than those receiving placebo.
Through different microscopy techniques, the structural related details of PP cells have been able to be better understood. This is inclusive of how big they are, what their cellular membranes look like, the proteins associated with them, and even their size. PP cells are elongated cells. Another one of these details can be noted in insulins secretory granules, or container like buds, that store insulin within a cell. In PP cells, the size of the insulin granules are smaller and spherical and similar to those in alpha cells. This is noted in human PP cells, but different animals have been shown to have different sized granules compared to humans, like rodents. In cats and dogs, PP cells have large granules. In rats, PP cells have few granules, similar to humans. In dogs, some PP cells are located in the walls of the antrum of the stomach.
In England, an estimated 2,189,300 people were thought to have tested positive for COVID-19. 14 January Four women and two children are injured in a drive-by mass shooting close to a Catholic church in Euston Road, Euston, Central London. A 22-year-old man is arrested two days later on suspicion of attempted murder. Amid recent heavy rain, more than 100 flood warnings by the Environment Agency remain in place across the country, with hundreds of homes damaged and many left without power. Rishi Sunak confirms that the UK will send 14 Challenger 2 tanks to Ukraine to boost its war effort. 16 January Serving Metropolitan Police officer David Carrick admits over 40 offences including more than 20 rapes against 12 women over two decades. The National Education Union announces that teachers in England and Wales will strike on seven dates during February and March after members voted in favour of strike action. National strikes will be held on 1 and 15 February, and 15 March, as well as four days of regional strikes. The UK government announces it will block the Gender Recognition Reform (Scotland) Bill, the first time that the UK government has used powers to block a Scottish law. UK ministers say the draft law would "conflict with equality protections applying across Great Britain". The Royal College of Nursing announces a further two nurses' strikes for 6 and 7 February, described as the biggest so far. MPs vote 309–249 in favour of the Strikes (Minimum Service Levels) Bill 2023, which now moves to the committee stage.
=== Surgery === Surgical removal of the pituitary tumor is usually effective in lowering growth hormone levels. Two surgical procedures are available for use. The first is endonasal transsphenoidal surgery, which involves the surgeon reaching the pituitary through an incision in the nasal cavity wall. The wall is reached by passing through the nostrils with microsurgical instruments. The second method is transsphenoidal surgery during which an incision is made into the gum beneath the upper lip. Further incisions are made to cut through the septum to reach the nasal cavity, where the pituitary is located. Endonasal transsphenoidal surgery is a less invasive procedure with a shorter recovery time than the older method of transsphenoidal surgery, and the likelihood of removing the entire tumor is greater with reduced side effects. Consequently, endonasal transsphenoidal surgery is the more common surgical choice. These procedures normally relieve the pressure on the surrounding brain regions and lead to a lowering of GH levels. Surgery is most successful in people with blood GH levels below 40 ng/ml before the operation and with pituitary tumors no larger than 10 mm in diameter. Success depends on the skill and experience of the surgeon. The success rate also depends on what level of GH is defined as a cure. The best measure of surgical success is the normalization of GH and IGF-1 levels. Ideally, GH should be less than 2 ng/ml after an oral glucose load.
Sources: en.wikipedia.org
Although still partially informed by older Liberal concerns for character, self-reliance, and the capitalist market, this legislation nevertheless, marked a significant shift in Liberal approaches to the state and social reform, approaches that later governments would slowly expand and that would grow into the welfare state after the Second World War. What was new in these reforms was the underlying assumption that the state could be a positive force, that the measure of individual freedom... was not how much the state left people alone, but whether it gave them the capacity to fill themselves as individuals. Contrasting Old Liberalism with New Liberalism, David Lloyd George noted in a 1908 speech the following:
== Career and research == After graduating, Hopkins then taught physiology and toxicology at Guy's Hospital from 1894 to 1898. In 1898, while attending a meeting of the Physiological Society, he was invited by Sir Michael Foster to join the Physiological Laboratory in Cambridge to investigate the chemical aspects of physiology. Biochemistry was not, at that time, recognised as a separate branch of science. He was a lecturer in chemical physiology at Emmanuel College, Cambridge in March 1900, when he received the academic rank Master of Arts (MA) honoris causa. He earned a doctorate in physiology (D.Sc.) from the University of London in July 1902, and at the same time was given a readership in biochemistry at Trinity College. While at Cambridge he was initiated into Freemasonry. In 1910 he became a Fellow of Trinity College, and an Honorary Fellow of Emmanuel College. In 1914 he was elected to the Chair of Biochemistry at Cambridge University, thus becoming the first Professor in that discipline at Cambridge. His Cambridge students included neurochemistry pioneer Judah Hirsch Quastel and pioneer embryologist Joseph Needham. Hopkins had for a long time studied how cells obtain energy via a complex metabolic process of oxidation and reduction reactions. His study in 1907 with Sir Walter Morley Fletcher of the connection between lactic acid and muscle contraction was one of the central achievements of his work on the biochemistry of the cell. He and Fletcher showed that oxygen depletion causes an accumulation of lactic acid in the muscle.
In April 2002, Yosri Fouda of Al Jazeera met al-Qaeda member Khalid Sheikh Mohammed and bin al-Shibh, who were in hiding, and they admitted to him their involvement in the attacks. Mohammed had been an organizer and financier of al-Qaeda's 1993 bombing of the World Trade Center, and he was the uncle of Ramzi Yousef, the lead bomber in that attack. Mohammed and Yousef planned another terrorist attack, the Bojinka plot, for January 1995. Despite its failure, and Yousef's imprisonment by the U.S. afterwards, the plot would influence the later September 11 attacks. The 2004 9/11 Commission Report determined that the animosity that Mohammed, the principal architect of 9/11, felt towards the U.S. had stemmed from his "violent disagreement with U.S. foreign policy favoring Israel."
DNA immunization can raise multiple TH responses, including lymphoproliferation and the generation of a variety of cytokine profiles. A major advantage of DNA vaccines is the ease with which they can be manipulated to bias the type of T-cell help towards a TH1 or TH2 response. Each type has distinctive patterns of lymphokine and chemokine expression, specific types of immunoglobulins, patterns of lymphocyte trafficking and types of innate immune responses.
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。