This is a working overview of prothymosin alpha, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-07-26. Anything still debated is marked as such rather than presented as settled.
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.
Thymosin alpha 1 is a short peptide of 28 amino acid residues that derives from the amino terminal region of a larger precursor protein known as prothymosin alpha. The peptide carries an acetyl group on its first residue and contains no disulfide bonds or carbohydrate chains. Its sequence is highly conserved across mammalian species, which is one reason laboratories treat it as a molecule with a defined and reproducible structure rather than a variable tissue extract. The name follows an early naming convention for thymus-derived fractions and does not imply that the peptide acts as a hormone in the classical endocrine sense.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular mass | Approximately 3,108 Da | Consistent with a 28-residue acetylated peptide |
| Residue count | 28 | Corresponds to the amino terminal region of prothymosin alpha |
| Appearance of dry powder | White to off-white solid | Slight variation between lots is normal |
| Solubility class | Freely soluble in water | Low solubility in most organic solvents |
| Common synonyms | Thymosin alpha 1, T alpha 1 | The numeral reflects an early fraction numbering scheme |
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.
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.
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.
Thymosin alpha-1 is a 28-residue peptide first isolated from thymus tissue in the 1970s. It corresponds to the N-terminal portion of thymosin beta-4, from which it is cleaved in vivo. The peptide carries an acetyl group at its N-terminus, a modification that affects its charge and stability. Synthetic material produced by solid-phase peptide synthesis is chemically identical to the natural fragment and is the form used in research and clinical studies.
== Clinical benefits == As a first-generation medication, golodirsen is far away from being curative; clinical trial outcomes have demonstrated it to have a marginal effect on ameliorating Duchenne muscular dystrophy pathology. As of December 2019, golodirsen is approved for therapeutic use in the United States, as well as in the countries that automatically recognize the decisions of the US Food and Drug Administration, under the condition that its benefit will be demonstrated in a confirmatory clinical trial.
=== 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.
AC/DC, an Australian rock music group ACDC (medicine), Arterial calcification due to deficiency of CD73 (ACDC), a rare genetic disorder Adiponectin, a peptide hormone All Campus Dining Center, a dining hall at Vassar College Asian Community Development Corporation, a community development organization headquartered in Boston ACDC (JoJo's Bizarre Adventure), also Esidisi, a character from the Japanese manga and anime JoJo's Bizarre Adventure in the story arc Battle Tendency ACDC, a dance crew led by Adam G. Sevani and Jon M. Chu Africa CDC, Africa Centres for Disease Control and Prevention Asymmetric counteranion directed catalysis, a type of chemical reaction
=== The Nobel Prize in Chemistry 1944 === On 16 November 1945 the Royal Swedish Academy of Sciences announced that Hahn had been awarded the 1944 Nobel Prize in Chemistry "for his discovery of the fission of heavy atomic nuclei." Hahn was still at Farm Hall when the announcement was made; thus, his whereabouts were a secret, and it was impossible for the Nobel committee to send him a congratulatory telegram. Instead, he learned about his award on 18 November through the Daily Telegraph. His fellow interned scientists celebrated his award by giving speeches, making jokes, and composing songs. Hahn had been nominated for the chemistry and the physics Nobel prizes many times even before the discovery of nuclear fission. Several more followed for the discovery of fission. The Nobel prize nominations were vetted by committees of five, one for each award. Although Hahn and Meitner received nominations for physics, radioactivity and radioactive elements had traditionally been seen as the domain of chemistry, and so the Nobel Committee for Chemistry evaluated the nominations. The committee received reports from Theodor Svedberg and Arne Westgren. These chemists were impressed by Hahn's work, but felt that of Meitner and Frisch was not extraordinary, and did not understand why the physics community regarded their work as seminal. As for Strassmann, although his name was on the papers, there was a long-standing policy of conferring awards on the most senior scientist in a collaboration. The committee therefore recommended that Hahn alone be given the chemistry prize.
Emerson University, Multan (formerly Government Emerson College, Multan) is a public-sector university in Multan, Punjab, Pakistan. The institution traces its origins to 1920 and was reconstituted as a degree-awarding university in 2021 under the Emerson University Multan Act 2021 (Punjab Act VIII of 2021).
Sources: en.wikipedia.org
== Role in metabolism == Sugar phosphates are major players in metabolism due to their task of storing and transferring energy. Not only ribose 5-phosphate but also fructose 6-phosphate are an intermediate of the pentose-phosphate pathway which generates nicotinamide adenine dinucleotide phosphate (NADPH) and pentoses from glucose polymers and their degradation products. The pathway is known as glycolysis where the same carbohydrates are degraded into pyruvates thus providing energy. Enzymes are catalysed for the reactions of these pathways. Some enzymes contain metal centers in their active site which is important part of the enzymes and as well as for the catalysed reaction. The phosphate group can coordinate to the metal center for example, 1,6-bisphosphatase and ADP-ribose pyrophosphatase. Phosphoglycerate and several sugar phosphates that are known intermediates of the Calvin photosynthetic carbon cycle, stimulate light-dependent carbon dioxide fixation by isolated chloroplasts. This ability is shared by certain other metabolites (e.g. glucose 1-phosphate) from which the accepted Calvin-cycle intermediates could easily be derived by known metabolic routes.
RGD-based peptides have found many applications in biological research and medical devices. Culture plates coated with peptides mimicking ECM proteins' adhesion motifs, which promote prolonged culture of human embryonic stem cells, are on the market. RGD is also a universally used tool in the construction of multifunctional "smart" materials, such as tumor-targeted nanoparticles. Further, RGD is widely used in tissue engineering to promote tissue regeneration.
== Oxygen-17 == Oxygen-17 (17O) is the rarest of the three stable isotopes of oxygen with a low isotopic abundance of about 0.038% = 380 ppm in terrestrial water and air. Naturally 17O is primarily made by burning hydrogen into helium in the CNO cycle, making it a common isotope in the hydrogen burning zones of stars. As the only stable isotope of oxygen possessing a nuclear spin (+5⁄2) and a favorable characteristic of field-independent relaxation in liquid water, through extreme motional narrowing.17O enables NMR studies tracing oxidative metabolic pathways (i.e. conversion of 17O2 gas to metabolically produced H217O water by oxidative phosphorylation in mitochondria) at high magnetic fields. This is a necessary requirement to overcome the low SNR from low abundance, low gyromagnetic ratio and fast quadrupolar transversal relaxation in contrast to proton/hydrogen, which is the most commonly used nucleus in magnetic resonance. Water used as nuclear reactor coolant is subjected to intense neutron flux. Natural water starts out with 0.038% of 17O; heavy water starts out incidentally enriched to about 0.055% in that isotopes. Further, the neutron flux slowly converts 16O in the cooling water to 17O by neutron capture, increasing its concentration. The neutron flux slowly converts 17O (with much greater cross section) in the cooling water to carbon-14, an undesirable product that can escape to the environment:
where P denotes the pressure of the system, V denotes the volume of the gas, k is a constant value representative of the temperature of the system and amount of gas. So long as temperature remains constant the same amount of energy given to the system persists throughout its operation and therefore, theoretically, the value of k will remain constant. However, due to the derivation of pressure as perpendicular applied force and the probabilistic likelihood of collisions with other particles through collision theory, the application of force to a surface may not be infinitely constant for such values of V, but will have a limit when differentiating such values over a given time. Forcing the volume V of the fixed quantity of gas to increase, keeping the gas at the initially measured temperature, the pressure P must decrease proportionally. Conversely, reducing the volume of the gas increases the pressure. Boyle's law is used to predict the result of introducing a change, in volume and pressure only, to the initial state of a fixed quantity of gas. The initial and final volumes and pressures of the fixed amount of gas, where the initial and final temperatures are the same (heating or cooling will be required to meet this condition), are related by the equation:
Sources: en.wikipedia.org
== Biochemistry == The stereoisomer (S)-1-pyrroline-5-carboxylate (also referred to as L-P5C) is an intermediate metabolite in the biosynthesis and degradation of proline and arginine. In prokaryotic proline biosynthesis, GSA is synthesized from γ-glutamyl phosphate by the enzyme γ-glutamyl phosphate reductase.
Nicotinamide riboside (NR) is now known to be an NAD precursor, involved in the biosynthetic pathways that convert B3 vitamins into NAD. NAD is primarily synthesized in mammals de novo from tryptophan, through the Priess-Handler pathway from nicotinic acid (NA) or via a salvage pathway from nicotinamide (NAM).
== Biosynthesis == Biosynthesis pathway of fumitremorgin pathway involves several different enzymes. FtmA is a nonribosomal peptide synthase. Both FtmB and FtmH are prenyltransferase. Three different cytochrome P450 monooxygenases involved in the biosynthesis of fumitremorgin C are FtmC, FtmE, and FtmG. Furthermore, FtmD is proposed to function as the methyltransferase. The synthesis starts with the formation of brevianamide F. FtmA catalyzes the nonribosomal peptide synthesis (NRPS) of this diketopiperazine product from two amino acids, L-tryptophan and L-proline. Then, another enzyme, FtmB, prenylates the product to form tryprostatin B. At this point, there are two separate pathways. FtmE may cyclize tryprostatin B to form demethoxyfumitremorgin C, or FtmC may oxidize tryprostatin B to form desmethyltrprostatin A by adding a hydroxyl group to the C-6 of the indole ring. The later pathway is followed by methylation to form tryprostatin A. The enzyme that catalyzes this methylation reaction has not been fully identified, but FtmD is suspected to be the plausible candidate. Then, the cyclization of tryprostatin A produces fumitremorgin C by forming the C-N bond by FtmE. The subsequent hydroxylation of fumitremorgin C takes place at C-12 and C-13 to form 12α, 13α-dihydroxyfumitremorgin C by FtmG. Fumitremorgin B is formed by another prenyltransferase, FtmH, that prenylates at N-1 of the indole ring (N-vinyl rather than N-prenyl incorrectly shown in the scheme below).
=== Names === It is often sold as a salt in the form of either codeine sulfate or codeine phosphate in the United States, United Kingdom, and Australia. Codeine hydrochloride is more common worldwide and the citrate, hydroiodide, hydrobromide, tartrate, and other salts are also seen. The chemical name for codeine is morphinan-6-ol, 7,8-didehydro-4,5-epoxy-3-methoxy-17-methyl-, (5α,6α)-
== Administration of ACAM2000 == The ACAM2000 vaccine is produced from the vaccinia virus, which is sufficiently closely related to smallpox to provide immunity, but the ACAM2000 vaccine cannot cause smallpox because it does not contain the smallpox virus. Other vaccines containing live viruses include measles, mumps, rubella, polio and chickenpox. The vaccine is administered using a bifurcated stainless steel needle. The needle is dipped into the vaccine solution and used to prick the skin several times in the upper arm. The vaccinia virus will begin to grow at the injection site. It will cause a localized infection, with a red itchy sore produced at the vaccination site within three to four days. If the infection occurs, that is an indication that the vaccine was successful. Ultimately, the sore turns into a blister and then dries up. A scab forms and then falls off in the third week, leaving a small scar behind.
Sources: en.wikipedia.org
The name reflects an early convention for naming thymus-derived fractions. The peptide is characterized and measured as a defined molecule, and it does not operate through a single classical endocrine axis.
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.