The short version of prothymosin alpha fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-04-12 and is reviewed periodically as new material appears.
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.
Lyophilized thymosin alpha-1 is generally stored at or below minus twenty degrees Celsius, protected from moisture and light. Short-term handling at ambient temperature is possible for dry powder, but reconstituted solutions degrade faster and are usually kept at two to eight degrees Celsius with a defined expiry of days rather than weeks. Repeated freeze-thaw cycles should be avoided because they promote aggregation and loss of potency. Exact limits depend on the formulation and should follow the supplier's documentation.
Thymosin alpha-1 is a synthetic peptide of 28 amino acid residues that corresponds to a naturally occurring fragment first isolated from thymus tissue. Its chain is acetylated at the amino terminus, a modification that shields the peptide from rapid cleavage by aminopeptidases. The molecule carries a net negative charge at physiological pH and dissolves freely in water. Researchers classify it as an immune-modulating agent rather than a classical hormone, because it acts on several cell types of both the innate and the adaptive immune system.
The peptide was identified during work in the 1970s on thymosin fraction 5, a partially purified extract of calf thymus. Investigators separated that mixture and characterized individual components, one of which they named thymosin alpha-1. The same compound later received the international nonproprietary name thymalfasin. Commercial material is produced by solid-phase peptide synthesis rather than by extraction, so synthetic and natural forms share an identical sequence. Naming conventions vary across the literature, and readers should distinguish the alpha-1 peptide from other thymosins that have unrelated sequences and functions.
Thymosin beta-4 is a separate 43-residue peptide that binds actin and participates in cell migration; it shares no sequence similarity with thymosin alpha-1 despite the common family name. Other preparative materials, such as thymosin fraction 5 and thymopoietin, contain distinct mixtures or peptides. The shared thymosin label reflects the tissue of origin used in early purification, not a common structural core. Treating these molecules as interchangeable is a frequent source of confusion in laboratory reports and in popular summaries alike.
| Property | Value | Notes |
|---|---|---|
| Storage temperature, powder | -20 °C or lower | Protect from light and moisture |
| Storage temperature, reconstituted | 2-8 °C | Use within days |
| Purity testing | Reversed-phase HPLC | Separates truncation products |
| Mass confirmation | Mass spectrometry | Detects deamidation and oxidation |
| Common salt forms | Acetate or trifluoroacetate | Affects solubility and weighing |
The name itself causes confusion, because several unrelated thymic peptides share the thymosin label. Thymosin beta-4, for example, is a different molecule with different functions. Naming conventions in the literature also mix descriptive research terms with assigned nonproprietary names, so a reader should confirm which entity a given paper addresses. Clarifying that point is usually the first step in interpreting any claim about this peptide.
Thymosin alpha-1 is a short peptide of 28 amino acid residues first described in the 1970s as a component of thymic extracts. Its N-terminal residue carries an acetyl group, and the sequence is highly conserved across mammalian species. The peptide is not encoded as a standalone gene product; it is released by proteolytic cleavage from the N-terminus of prothymosin alpha, a larger acidic nuclear protein. That precursor relationship places it within a broader family of thymic and immune-associated peptides that have been studied for decades.
The activity of this peptide is generally described as immunomodulatory rather than directly antimicrobial. Experimental work links it to signaling through certain Toll-like receptors on dendritic cells and to downstream maturation of antigen-presenting cells. Reported effects include expansion of T cell subsets, shifts in cytokine profiles, and increased natural killer cell activity. These observations come largely from cell culture and animal models, and the precise receptor-level events in humans remain incompletely characterized.
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.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
== External links == Controlled vocabulary of post-translational modifications in Uniprot List of posttranslational modifications in ExPASy Browse SCOP domains by PTM — from the dcGO database Overview and description of commonly used post-translational modification detection techniques
== History of the term == The term "RuBisCO" was coined humorously in 1979, by David Eisenberg at a seminar honouring the retirement of the early, prominent RuBisCO researcher, Sam Wildman, and also alluded to the snack food trade name "Nabisco" in reference to Wildman's attempts to create an edible protein supplement from tobacco leaves. The capitalization of the name has been long debated. It can be capitalized for each letter of the full name (Ribulose-1,5 bisphosphate carboxylase/oxygenase), but it has also been argued that is should all be in lower case (rubisco), similar to other terms like scuba or laser.
=== 9 January === Russia and Ukraine conducted their 36th prisoner swap of the conflict, with each side trading 50 POWs to the other. Ukraine's regional prosecutor's office claimed that an S-300 fired from Belgorod Oblast hit a market in Shevchenkove, killing two women, wounding a child, and damaging a shopping centre. A spokesperson stated that Germany had no plans to provide the Leopard 2 to Ukraine.
Sources: en.wikipedia.org
Due to the high volume or water content of fiber-rich foods, fiber displaces available calories and nutrients from the diet. Consumption of viscous fibers delays gastric emptying, which may cause an extended feeling of fullness. Satiety is also induced by increasing chewing, which limits food intake by promoting the secretion of saliva and gastric juice, resulting in an expansion of the stomach. In addition, hormone secretion is affected during fiber ingestion. Insulin response is reduced and cholecystokinin (CCK) in the small intestine is increased. Insulin regulates blood glucose levels while CCK adjusts gastric emptying, pancreatic secretion, and gall bladder contraction. There is a direct correlation between CCK and satiety after foods of different fiber contents are consumed. In general, large intakes of dietary fiber at breakfast have been associated with less food intake at lunchtime. Fiber may have the added benefit of helping consumers reduce food intake throughout the day, but results of studies examining this possibility have been conflicting.
== Venom == The venom of this species is not well studied, but it is believed that the venom is dangerously neurotoxic, like that of most elapids. A study listed the intraperitoneal (IP) LD50 of this species at 0.143 mg/kg. Venoms of the water cobras were assayed for lethality, proteolytic activity and protein content. Naja annulata annulata and Naja christyi venoms averaged 89% protein and lacked proteolytic activity. The murine intraperitoneal LD50 of N. a. annulata and N. christyi venoms were 0.143 and 0.120 mg/kg, respectively. Polyvalent antivenom produced by the South African Institute of Medical Research neutralized 575 and 200 LD50 of N. a. annulata and N. christyi venoms/ml antivenom, respectively. Cation exchange chromatography resolved four lethal peaks from N. a. annulata venom and six lethal peaks from N. christyi venom. The major lethal peaks (about 12% of total venom protein) were purified further with molecular sieve chromatography and were characterized as 61- (N. a. annulata toxin) and 62-residue (N. christyi toxin) polypeptides with four half-cystines. Elucidation of the complete amino-acid sequences indicated that these toxins belonged to the short-chain class of postsynaptic neurotoxins. Short-chain neurotoxins 1 from N. a. annulata and N. christyi had murine intraperitoneal LD50 values of 0.052 and 0.083 mg/kg, respectively, and showed over 80% homology with N. nigricollis alpha toxin. Reverse-phase analysis of another peak present in both venoms resolved a toxin that had an N-terminus identical to N. christyi short-chain neurotoxin 1.
Improper disposal of the radionuclide cobalt-60, used in cobalt guns for radiotherapy, has led to serious radiation accidents, such as the Ciudad Juárez (Mexico) radiological accident in 1983/84, the Goiânia (Brazil) accident in 1987, the Samut Prakan (Thailand) nuclear accident in 2000, and the Mayapuri (India) accident in 2010. Eleven Therac-25 linear accelerators were built by the Canadian company Atomic Energy of Canada Limited (AECL) between 1982 and 1985 and installed in clinics in the United States and Canada. Software errors and a lack of quality assurance led to a serious malfunction that killed three patients and seriously injured three others between June 1985 and 1987 before appropriate countermeasures were taken. The radiation exposure in the six cases was subsequently estimated to be between 40 and 200 Gray; normal treatment is equivalent to a dose of less than 2 Gray. Around 1990, about one hundred cobalt guns were still in use in Germany. In the meantime, electron linear accelerators were introduced and the last cobalt gun was decommissioned in 2000.
==== Shotgun sequencing ==== High throughput shotgun sequencing using tools such as Solexa or Illumina yields approximately 5 million sequence tags per sample of maternal serum. Aneuploid pregnancies such as trisomy were identified when testing at the fourteenth week of gestation. Fetal whole of genome mapping by parental haplotype analysis was completed using sequencing of cffDNA from maternal serum. Pregnant females were studied using a 2-plex massively parallel maternal plasma DNA sequencing and trisomy was diagnosed with z-score greater than 3. The sequencing gave sensitivity of 100 percent, specificity of 97.9 percent, a positive predictive value of 96.6 percent and a negative predictive value of 100 percent.
Sources: en.wikipedia.org
Dry lyophilized powder tolerates short ambient exposure during handling and shipping. Long-term room-temperature storage is not recommended because moisture uptake and slow degradation can occur over months. Storage at minus twenty degrees Celsius is the common practice for extended periods.
Typical entries list appearance, identity by mass spectrometry, purity by chromatography, water or moisture content, and residual counter-ion. Some certificates also report microbial limits and endotoxin for materials intended for laboratory use. The reported methods and acceptance ranges vary between suppliers.
The peptide is often supplied as an acetate or trifluoroacetate salt, and the counter-ion affects solubility, weight-per-mole calculations, and compatibility with cell assays. Trifluoroacetate can be undesirable in some biological experiments. Knowing the salt form is necessary for accurate concentration determination.
It is a 28-residue synthetic peptide studied as an immune-modulating agent and approved as a drug in some countries. The sequence matches a naturally occurring fragment isolated from thymus tissue. It is not a hormone in the endocrine sense.