A practical reference on prothymosin alpha: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-11-23 and is reviewed periodically as new material appears.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
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.
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 |
|---|---|---|
| Molecular formula | C129H215N33O55 | Calculated for the acetylated 28-residue peptide |
| Appearance | White to off-white powder | Lyophilized solid recovered from aqueous buffer |
| Solubility | Freely soluble in water | Typically dissolved in water or buffer before use |
| Typical storage | -20 C or below, desiccated | Protect from light and avoid repeated freeze-thaw cycles |
| Identity testing | Reverse-phase HPLC with mass spectrometry | Retention time and measured mass confirm the sequence |
Routine handling calls for storage of the lyophilized powder at refrigerated temperatures, away from light, in a sealed container. Working solutions are often prepared in sterile water or buffer and kept cold between uses. Repeated freeze-thaw cycles are generally avoided because they can promote aggregation and loss of material. Laboratories usually record lot number, reconstitution date, and storage conditions so that any change in behavior can be traced to a specific preparation.
Reverse-phase high-performance liquid chromatography is the standard technique for assessing purity and concentration, because the peptide's hydrophobicity allows clean separation from related impurities. Mass spectrometry confirms molecular identity and detects sequence errors or truncations. Amino acid analysis and peptide mapping supply additional structural confirmation when required. Chromatographic purity values reported on certificates of analysis describe the proportion of the main peak and do not by themselves establish biological activity.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
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。
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。
Identity and purity are normally assessed by reversed-phase high-performance liquid chromatography, which separates the peptide from related impurities and truncation products. Mass spectrometry confirms molecular mass and detects modifications such as deamidation or oxidation. Amino acid analysis and peptide mapping provide additional sequence-level confirmation. For research material, a certificate of analysis typically reports these results together with water content and counter-ion identity, since the lyophilized powder is often supplied as an acetate or trifluoroacetate salt.
Several factors accelerate degradation: alkaline pH, elevated temperature, exposure to oxidants, and the presence of residual moisture. Deamidation of asparagine residues and oxidation of methionine are the most commonly reported degradation routes. Because the peptide lacks disulfide bonds, it does not undergo the thiol-related aggregation seen in some other biologics, but physical aggregation can still occur at high concentration. Stability data are product-specific, and extrapolating shelf life between formulations is not reliable.
The conservation and restoration of herbaria includes the preventive care, repair, and restoration of herbarium specimens. Collections of dried plant specimens are collected from their native habitats, identified by experts, pressed, and mounted onto archival paper. Care is taken to make sure major morphological characteristics are visible. Herbaria documentation provides a record of botanical diversity. Professionals who make decisions about the conservation-restoration of botanical specimens include registrars, curators, and conservators who work on herbarium collections in universities and museums. Herbarium specimens may be susceptible to water damage, mold, pests, unattached specimens, dust, dirt, and damage from improper storage conditions. Preventive conservation can prevent much of the damage that could occur.
Gaza war: David Cameron, the new foreign secretary, announces sanctions against four senior Hamas leaders and two of the militant group's financiers. Chelsea Ladies Football Club manager Emma Hayes is named as the new manager of the United States women's national football team, and will take up the role in May 2024. 15 November Inflation falls to 4.6%, the lowest rate since November 2021, driven mainly by lower energy prices. The British Government's plan to deport migrants to Rwanda is ruled as unlawful by the Supreme Court. Sunak says the government will introduce "emergency legislation" to enable Parliament to "confirm Rwanda is safe" and prevent legal challenges from blocking the migrant policy. More than 50 Labour MPs defy Sir Keir Starmer to vote for an immediate ceasefire in the Israel-Hamas war. The General Synod of the Church of England votes to allow special church services of blessing for gay couples. 16 November David Cameron makes his first working visit to Ukraine as foreign secretary, where he meets President Volodymyr Zelensky in Kyiv, and reiterates the UK's promise to provide moral, diplomatic and "above all military support for... however long it takes". Train drivers union ASLEF announces new strike dates, with a rolling programme of strikes from 2 to 8 December affecting different train companies on different days. A sixth person is confirmed dead following a house fire in Hounslow, West London.
Some have active camouflage that changes with need. Distraction eye, many fish have spot on the tail to fool potential predators and prey; both are not sure which is the front, the direction of travel. Gills appear in unrelated fish, some amphibians, some crustacean, aquatic insects and some mollusk, like freshwater snails, squid, octopus.
Sources: en.wikipedia.org
=== Among other animals === The hedgehog (Erinaceidae), the mongoose (Herpestidae), the honey badger (Mellivora capensis) and the opossum are known to be resistant to a dose of snake venom. Recently, the honey badger and domestic pig were found to have convergently evolved amino-acid replacements in their nicotinic acetylcholine receptor, which are known to confer resistance to alpha-neurotoxins in hedgehogs. Whether the pig may be considered immune is still uncertain, though early studies show endogenous resistance in pigs tested against neurotoxins. Though the pig's subcutaneous layer of fat may protect it against snake venom, most venoms pass easily through vascular fat layers, making this unlikely to contribute to its ability to resist venoms. The garden dormouse (Eliomys quercinus) has recently been added to the list of animals refractory to viper venom. Some populations of California ground squirrel (Otospermophilus beecheyi) are at least partially immune to rattlesnake venom as adults.
==== pH regulation ==== Secretin primarily functions to neutralize the pH in the duodenum, allowing digestive enzymes from the pancreas (e.g., pancreatic amylase and pancreatic lipase) to function optimally. Secretin targets the pancreas; pancreatic centroacinar cells have secretin receptors in their plasma membrane. As secretin binds to these receptors, it stimulates adenylate cyclase activity and converts ATP to cyclic AMP. Cyclic AMP acts as second messenger in intracellular signal transduction and causes the organ to secrete a bicarbonate-rich fluid that flows into the intestine. Bicarbonate is a base that neutralizes the acid, thus establishing a pH favorable to the action of other digestive enzymes in the small intestine. Secretin also increases water and bicarbonate secretion from duodenal Brunner's glands to buffer the incoming protons of the acidic chyme, and also reduces acid secretion by parietal cells of the stomach. It does this through at least three mechanisms: 1) By stimulating release of somatostatin, 2) By inhibiting release of gastrin in the pyloric antrum, and 3) By direct downregulation of the parietal cell acid secretory mechanics. It counteracts blood glucose concentration spikes by triggering increased insulin release from pancreas, following oral glucose intake.
Neuroimaging studies using resting state fMRI recently suggested that LSD changes the cortical functional architecture. These modifications spatially overlap with the distribution of serotonergic receptors. In particular, increased connectivity and activity were observed in regions with high expression of 5-HT2A receptor, while a decrease in activity and connectivity was observed in cortical areas that are dense with 5-HT1A receptor. Experimental data suggest that subcortical structures, particularly the thalamus, play a synergistic role with the cerebral cortex in mediating the psychedelic experience. LSD, through its binding to cortical 5-HT2A receptors, may enhance excitatory neurotransmission along frontostriatal projections and, consequently, reduce thalamic filtering of sensory stimuli towards the cortex. This phenomenon appears to involve ventral, intralaminar, and pulvinar nuclei selectively.
Hormones are signaling molecules produced by specialized cells in various human tissues and organs. They regulate diverse physiological processes by binding to specific receptors. Human hormones are commonly grouped into four major structural classes:
Sources: en.wikipedia.org
== Adverse effects == People have had severe infusion-related reactions to pembrolizumab. There have also been severe immune-related adverse effects including lung inflammation (including fatal cases) and inflammation of endocrine organs that caused inflammation of the pituitary gland, of the thyroid (causing both hypothyroidism and hyperthyroidism in different people), and pancreatitis that caused Type 1 diabetes and diabetic ketoacidosis; some people have had to go on lifelong hormone therapy as a result (e.g. insulin therapy or thyroid hormones). People have also had colon inflammation, liver inflammation, kidney inflammation due to the drug. The common adverse reactions have been fatigue (24%), rash (19%), itchiness (pruritus) (17%), diarrhea (12%), nausea (11%) and joint pain (arthralgia) (10%). Other adverse effects occurring in between 1% and 10% of people taking pembrolizumab have included anemia, decreased appetite, headache, dizziness, distortion of the sense of taste, dry eye, high blood pressure, abdominal pain, constipation, dry mouth, severe skin reactions, vitiligo, various kinds of acne, dry skin, eczema, muscle pain, pain in a limb, arthritis, weakness, edema, fever, chills, myasthenia gravis, and flu-like symptoms.
On 4 June, Hezbollah rejected the truce deal announced the previous day and instead demanded a comprehensive truce and full withdrawal of Israel from Lebanon. On 19 June, an American official said that Israel and Hezbollah agreed to a truce mediated by the US, Qatar and Iran. On 26 June, US Secretary of State Marco Rubio announced a framework deal between Israel and Lebanon for "lasting peace and security" via US mediation. The agreement includes a cease-fire, requiring Hezbollah to end hostilities and withdraw from southern Lebanon, but it was subsequently rejected by Hezbollah.
=== Specific zones === Specific zones are associated with sexual response, and include the lips and nipples in addition to areas of the genitals, notably corona of the glans penis, the foreskin, clitoris and perianal skin. These zones have a high density of innervation, and may have an efficiency of wound healing and a capacity to stimulate generalized cerebral arousal.
=== Solve rate === Although advances in forensic science and investigative techniques have helped solve many older cases, a substantial number of homicides remain unsolved each year in the United States, resulting in a growing backlog of cold cases.
====== Interferons ====== Type I and type II interferons have anticancer activity (see the "Function" section in the "Interferon" article). Interferons can promote expression of major histocompatibility complex molecules, MHC I and MHC II, and stimulate immunoproteasome activity. All interferons drastically increase the presentation of MHC I dependent antigens. Interferon gamma (IFN-gamma) also strongly promotes the MHC II-dependent presentation of antigens. Higher MHC I expression leads to higher presentation of viral and abnormal peptides from cancer cells to cytotoxic T cells, while the immunoproteasome more efficiently processes these peptides for loading onto the MHC I molecule. Therefore, the recognition and killing of infected or malignant cells increases. Higher MHC II expression enhances presentation of viral and cancer peptides to helper T cells; which are releasing cytokines (such as more interferons, interleukins and other cytokines) that stimulate and co-ordinate the activity of other immune cells. By down regulation of angiogenic stimuli produced by tumor cells interferon can also suppress angiogenesis In addition, they suppress the proliferation of endothelial cells. Such suppression causes a decrease in tumor vascularization and subsequent growth inhibition. Interferons can directly activate immune cells including macrophages and natural killer cells. INF-1 and interferon gamma (IFN-γ) production are triggered by SeV molecular components in many cells (See "Virus-induced antiviral immunity" section above).
Sources: en.wikipedia.org
It is a 28-amino-acid peptide originally purified from a bovine thymic extract and later produced synthetically. It is studied mainly for its effects on immune cell function.
No. The two peptides share part of a name but differ in length, sequence, and net charge. Literature searches that treat them as one compound return misleading results.
Solid-phase peptide synthesis is the usual route, and recombinant expression has also been described. Both approaches produce material matching the natural sequence.
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.