If you have been reading about Thymosin fraction 5 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 2025-08-31. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound has been investigated as an adjunct in chronic viral hepatitis and as a vaccine adjuvant, with results that vary by study design and population. Regulators in some countries have approved a synthetic form for specific indications, while other agencies have not. Whether the peptide produces consistent clinical benefit across diverse patient groups is still an open question, and many trials have been small. Its status is therefore best described as investigational in many contexts and established only narrowly.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Residue count | 28 amino acids | Acetyl group on the first residue |
| Approximate molecular mass | 3108 daltons | Calculated from the consensus sequence |
| Origin | Cleavage product of prothymosin alpha | Not encoded as a separate gene product |
| Primary research focus | Immune modulation | Studied in viral hepatitis and as a vaccine adjuvant |
| Common synonyms | Thymalfasin, Tα1, thymosin alpha 1 | Thymalfasin is the assigned nonproprietary name |
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.
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.
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.
Recommended storage for the dry powder is a freezer near minus twenty degrees Celsius, kept desiccated and away from light. Once dissolved, the peptide is less stable and is usually held at two to eight degrees Celsius for short intervals or frozen for longer storage. Stability studies focus on the acetylated terminus and the disulfide linkage because those features define the intact molecule. Common degradation routes include cysteine oxidation, deamidation of asparagine or glutamine side chains, and slow formation of higher-molecular-weight species.
Identity and purity are usually checked by reverse-phase high-performance liquid chromatography, which separates the intact chain from truncated products, together with mass spectrometry for confirmation of the expected mass. Peptide mapping after enzymatic digestion and amino acid analysis add sequence-level evidence. Release testing also covers water content, residual solvents, and counter-ions, all of which influence measured mass and stability. Related-peptide limits are commonly expressed as a percentage of total peak area, with individual unspecified impurities held below a lower threshold.
The lyophilized peptide is a white to off-white powder that dissolves freely in water and in aqueous buffers near neutral pH. Because the molecule carries a net negative charge under physiological conditions, saline and phosphate solutions are the usual vehicles, while strongly acidic media are avoided. Stock solutions are commonly divided into small aliquots so that repeated freezing and thawing can be limited, since cycling may encourage aggregation. Solubility in organic solvents is poor and those solvents are seldom used as primary diluents.
The most important isotope for nuclear power applications is uranium-235. It is used in the thermal reactor, and its concentration in natural uranium does not exceed 0.72%. This isotope strongly absorbs thermal neutrons releasing much energy. One fission act of 1 gram of 235U converts into about 1 MW·day. Of importance, is that 23592U emits more neutrons than it absorbs; upon reaching the critical mass, 23592U enters into a self-sustaining chain reaction. Typically, uranium nucleus is divided into two fragments with the release of 2–3 neutrons, for example:
A 2023 study also found evidence that Neanderthal single nucleotide polymorphisms (SNPs) likely play a "significant role" in autism susceptibility and heritability in autism populations across the United States. According to the study, "Although most studies on autism genomics focus on the deleterious nature of variants, there is the possibility some of these autism-associated Neanderthal SNPs have been under weak positive selection. In support, recent studies have identified genetic variants implicated in both autism and high intelligence. Meanwhile, autistic people often perform better on tests of fluid intelligence than neurotypicals." Another 2017 study that analyzed 68 genes associated with neurodevelopmental disorders, including autism, found that these disorders were also affected by natural selection and interbreeding between Homo sapiens and other archaic human species. The study also recommended further research into the link between Neanderthal single nucleotide polymorphisms (SNPs) and neurodevelopmental disorders, including autism, in modern-day humans.
== Sources == Clark, Andrew (20 February 1904). "The Army Council and Military Medical Administration". The British Medical Journal. 1 (2251): 442. JSTOR 20279611. Faught, C. Brad (2016). Kitchener: Hero and Anti-Hero. London and New York, I.B. Tauris. ISBN 978-1784533502. https://Discovery.NationalArchives.gov.uk/details/r/C259pen-government-licence/version/3/ (Open Government Licence v3.0) Crown copyright
=== Catalytic reforming === In catalytic reforming, a mixture of hydrocarbons with boiling points between 60 and 200 °C is blended with hydrogen gas and then exposed to a bifunctional platinum chloride or rhenium chloride catalyst at 500–525 °C and pressures ranging from 8–50 atm. Under these conditions, aliphatic hydrocarbons form rings and lose hydrogen to become aromatic hydrocarbons. The aromatic products of the reaction are then separated from the reaction mixture (or reformate) by extraction with any one of a number of solvents, including diethylene glycol or sulfolane, and benzene is then separated from the other aromatics by distillation. The extraction step of aromatics from the reformate is designed to produce aromatics with lowest non-aromatic components. Recovery of the aromatics, commonly referred to as BTX (benzene, toluene and xylene isomers), involves such extraction and distillation steps. In similar fashion to this catalytic reforming, UOP and BP commercialized a method from LPG (mainly propane and butane) to aromatics.
Cheese consists of proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. It is produced by coagulation that is caused by destabilization of the casein micelle, which begins the processes of fractionation and selective concentration. Typically, the milk is acidified and then coagulated by the addition of rennet, containing a proteolytic enzyme known as rennin; traditionally obtained from the stomachs of calves, but currently produced more often from genetically modified microorganisms. The solids are then separated and pressed into final form. Unlike many proteins, casein is not coagulated by heat. During the process of clotting, milk-clotting proteases act on the soluble portion of the caseins, κ-casein, thus originating an unstable micellar state that results in clot formation. When coagulated with chymosin, casein is sometimes called paracasein. Chymosin (EC 3.4.23.4) is an aspartic protease that specifically hydrolyzes the peptide bond in Phe105-Met106 of κ-casein, and is considered to be the most efficient protease for the cheese-making industry (Rao et al., 1998). British terminology, on the other hand, uses the term caseinogen for the uncoagulated protein and casein for the coagulated protein. As it exists in milk, it is a salt of calcium.
Sources: en.wikipedia.org
The primers used must be specific to the targeted sequences in the DNA of a virus, and PCR can be used for diagnostic analyses or DNA sequencing of the viral genome. The high sensitivity of PCR permits virus detection soon after infection and even before the onset of disease. Such early detection may give physicians a significant lead time in treatment. The amount of virus ("viral load") in a patient can also be quantified by PCR-based DNA quantitation techniques (see below). A variant of PCR (RT-PCR) is used for detecting viral RNA rather than DNA: in this test the enzyme reverse transcriptase is used to generate a DNA sequence that matches the viral RNA; this DNA is then amplified as per the usual PCR method. RT-PCR is widely used to detect the SARS-CoV-2 viral genome. Diseases such as pertussis (or whooping cough) are caused by the bacteria Bordetella pertussis. This bacteria is marked by a serious acute respiratory infection that affects various animals and humans and has led to the deaths of many young children. The pertussis toxin is a protein exotoxin that binds to cell receptors by two dimers and reacts with different cell types such as T lymphocytes which play a role in cell immunity. PCR is an important testing tool that can detect sequences within the gene for the pertussis toxin. Because PCR has a high sensitivity for the toxin and a rapid turnaround time, it is very efficient for diagnosing pertussis when compared to culture.
Elena Molokhovets's classic Russian cookbook A Gift to Young Housewives gives the first known recipe for Govjadina po-strogonovski, s gorchitseju, "Beef à la Stroganov, with mustard", in its 1871 edition. The recipe involves beef cubes (not strips) prepared in a dry marinade of salt and allspice, and then sautéed in butter. The sauce is a simple roux mixed with prepared mustard and broth, and finished with a small amount of sour cream: no onions, no mushrooms and no alcohol. In 1891, the French chef Charles Brière, who was working in Saint Petersburg, submitted a recipe for beef Stroganoff to a competition sponsored by the French magazine L'Art culinaire. This led Larousse Gastronomique to assume that he was the inventor of this dish, but both the recipe and the name existed before then.
=== DES litigation === Lilly was one of numerous manufacturers of diethylstilbestrol (DES), a synthetic estrogen that was prescribed to pregnant women to prevent pregnancy complications such as miscarriage. In 1971, researchers linked prenatal DES exposure to clear-cell adenocarcinoma of the vagina and cervix. The Food and Drug Administration responded by advising physicians not to prescribe DES to pregnant women. More than 300 companies manufactured DES, which later complicated litigation because plaintiffs often could not identify which manufacturer had supplied the drug taken by their mothers. In Bichler v. Eli Lilly and Company, Joyce Bichler sued Lilly after developing cervical and vaginal cancer at age 17 following prenatal exposure to DES. In 1982, the New York Court of Appeals upheld a $500,000 jury award to Bichler even though it had not been established that Lilly manufactured the particular DES taken by her mother. In the 1989 case Hymowitz v. Eli Lilly and Company, the New York Court of Appeals adopted a form of market share liability for DES cases that allowed liability to be apportioned among manufacturers according to their share of the national DES market when the specific producer could not be identified. DES litigation continued for decades. In 2013, Lilly reached an undisclosed settlement during a federal trial brought by four sisters who alleged that their breast cancers resulted from DES their mother had taken during pregnancy. Lilly disputed that DES caused their cancers and disputed whether their mother had taken DES manufactured by Lilly.
In fact, penicillin is soluble in ethanol, ether and chloroform. Further research was undertaken in the early 1930s by others including Harold Raistrick who confirmed the chemical instability of penicillin in 1932. While Fleming continued to send samples of the mould to researchers, the requests for samples tapered off.
== History == Little Caesars Pizza was founded on May 8, 1959, by the married couple Mike Ilitch and Marian Ilitch. The first location was in a strip mall in Garden City, Michigan, a suburb of Detroit, and named "Little Caesar's Pizza Treat". The original store closed in October 2018, relocating down the street to a new building in nearby Westland. The first Little Caesar's franchise location opened in 1962 in Warren, Michigan, and was still called Little Caesar's Pizza Treat. The same year the Little Caesar's logo became a 3D figure and was used in outdoor signage.
Sources: en.wikipedia.org
=== Relationship to Donald Trump === A key reason for Hillbilly Elegy's widespread popularity following its publication in 2016 was its role in explaining Donald Trump's rise to the top of the Republican Party. In particular, it purportedly explains why white, working-class voters became attracted to Trump as a political leader. Vance himself offered commentary on how his book provides perspective on why a voter from the "hillbilly" demographic would support Trump. Although he does not mention Trump in the book, Vance openly criticized the then presidential candidate while discussing his memoir in a 2016 interview following the book's release. Vance walked these comments back when he joined the 2022 U.S. Senate race in Ohio, and later openly endorsed Trump. In July 2024, Vance was picked by Trump to be his running mate on the Republican ticket for the 2024 U.S. presidential election.
In November 1997 National Theatre of Greece launched a worldwide tour of Medea, a critically acclaimed production directed by Nikaiti Kontouri, starring Karyofyllia Karambeti as Medea, Kostas Triantafyllopoulos as Creon and Lazaros Georgakopoulos as Jason. The tour included performances in France, Australia, Israel, Portugal, United States, Canada, Turkey, Bulgaria, China and Japan and lasted almost two years, until July 1999. The play opened in the United States at Shubert Theatre in Boston (18 and 19 September 1998) and then continued at City Center Theatre in Manhattan, New York City (23 to 27 September 1998), receiving a very positive review from The New York Times. Neil LaBute wrote Medea Redux, a modern retelling, first performed in 1999 starring Calista Flockhart, as part of his one-act trilogy entitled Bash: Latter-Day Plays. In this version, the main character is seduced by her middle-school teacher. He abandons her, and she kills their child out of revenge. Michael John LaChiusa created a Broadway musical adaptation work for Audra McDonald entitled Marie Christine in 1999. McDonald portrayed the title role, and the show was set in 1890s New Orleans and Chicago. Liz Lochhead's Medea previewed at the Old Fruitmarket, Glasgow as part of Theatre Babel's Greeks in 2000 before the Edinburgh Fringe and national tour. "What Lochhead does is to recast MEDEA as an episode-ancient but new, cosmic yet agonisingly familiar- in a sex war which is recognisable to every woman, and most of the men, in the theatre", wrote The Scotsman.
=== Radionuclides with half-lives of 1 day to 10 years === Ordered by half-life. The second half-life column in this table has been made unsortable, as the mixture of days and years will not sort properly. Resorting by half-life may be done no less by using the number or the half-life in seconds columns.
=== Acetate utilization === The acetate utilization test is used primarily to differentiate between Escherichia coli from members of the genus Shigella. Many of the Escherichia coli strains have the capability of the utilization of acetate for a sole carbon and energy source, while Shigella does not. Since acetate utilization results in an increase in pH, an indicator is added that changes color under conditions of acetate utilization.
=== Androgen signaling === The androgen response mechanism involves androgens binding to androgen receptors in the cytoplasm, which then move into the nucleus and control gene transcription by interacting with specific DNA regions called androgen response elements. This response mechanism is involved in male sexual differentiation and puberty, as well as other tissue types and processes, such as the prostate gland (regulate secretory functions), hair follicles (androgens influence hair growth patterns), skin (androgens regulate sebum production and the thickening and maturation of the skin), and muscle (contribute to the development and maintenance of muscle mass and strength). Such tissues, where androgens exert their effects, are called 'androgen target tissues'. Different androgens have different effects on androgen receptors because they have different degrees of binding and activating the receptors. Physiologically significant androgens are those androgens that have a strong influence on the development and functioning of male sexual characteristics, unlike physiologically insignificant androgens, which have low biological activity or are quickly metabolized into other steroids. Physiologically insignificant androgens do not have a notable influence on the development and functioning of male or female sexual characteristics, they can be products of the metabolism of more active androgens, such as testosterone (T), or their precursors.
Sources: en.wikipedia.org
It is usually classified as an immunomodulatory peptide rather than a classical hormone. It derives from the larger protein prothymosin alpha and acts mainly on immune cells. The thymosin label covers a group of distinct peptides, so the naming can be misleading.
The two share a family name but have different sequences, sizes, and functions. Thymosin beta-4 is a 43-residue peptide associated with actin binding and cell migration. Thymosin alpha-1 is a 28-residue peptide linked mainly to immune signaling.
Thymalfasin is the assigned international nonproprietary name for the synthetic 28-residue peptide. Thymosin alpha-1 is the descriptive research name for the same molecule. Which term appears depends on the context and the regulatory document.
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.