This is a working overview of thymalfasin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-02 and is reviewed periodically as new material appears.
Thymosin alpha-1 is a synthetic peptide of 28 amino acids whose sequence matches the amino-terminal region of prothymosin alpha. The chain is acetylated at its first residue and contains one disulfide bridge between two cysteine residues, which folds the molecule into a compact loop. Its molecular formula, C129H215N33O55, corresponds to a monoisotopic mass of roughly 3,106 daltons. Material used in laboratories is made by solid-phase synthesis rather than isolated from animal tissue.
Early work on thymic extracts in the 1960s described a heat-stable acidic fraction containing many polypeptides. Separation of that mixture yielded individual components, and thymosin alpha-1 was named as one of them on the basis of assays for T-cell activity. The first preparations came from calf thymus, while subsequent research and clinical material has been chemically synthesized. Nomenclature in older papers is inconsistent, and the same peptide sometimes appears under different designations, which complicates literature searches.
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.
| Property | Value | Notes |
|---|---|---|
| Class | Synthetic peptide | 28 residues; not a small-molecule compound |
| Molecular mass | About 3,106 Da | Monoisotopic mass of the unmodified chain |
| N-terminal group | Acetylated serine | Present in both native and synthetic forms |
| Secondary structure | Disulfide-constrained loop | One bridge between two cysteine residues |
| Typical source | Solid-phase synthesis | Early isolates came from bovine thymus extracts |
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.
Laboratory work indicates that the peptide acts on cells of both the innate and adaptive immune systems. Reported effects include signalling through Toll-like receptors on dendritic cells, enhanced T-cell maturation, and increased natural killer cell activity. These actions are described largely from cell-culture and animal experiments, and the precise receptor-level events remain incompletely defined. Studies in humans have generally measured immune markers rather than a single defined molecular target. The resulting picture remains partly descriptive.
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.
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Operation Silk Purse, for the Commander in Chief, U.S. European Command (USCINCEUR), based at RAF Mildenhall in the United Kingdom (callsign Seabell) Operation "Scope Light", for the Commander in Chief, U.S. Atlantic Command (CINCLANT), based at Langley AFB, VA Operation "Blue Eagle", for the Commander in Chief, U.S. Pacific Command (USCINCPAC), based at Hickam AFB, HI Operation "Nightwatch", which supported the President of the United States, and were based at Andrews AFB, Maryland. In the early 1970s the E-4A aircraft replaced the EC-135Js on this mission. The Eastern Auxiliary (EAST Aux) and Western Auxiliary (West Aux) Command Posts were also part of the WWABNCP ("wah-bin-cop") network and were capable of assuming responsibility for Looking Glass as the anchor. The West Aux 906th Air Refueling Squadron was based at Minot AFB, North Dakota, and moved to the 4th Airborne Command and Control Squadron at Ellsworth AFB, South Dakota in April 1970. The East Aux mission 301st Air Refueling Squadron was based at Lockbourne AFB, Ohio. In April 1970, the role moved to the 3rd Airborne Command & Control Squadron at Grissom AFB, Indiana. After 1975, East Aux was assumed from the Looking Glass backup ground alert aircraft launched from Offutt AFB. In June 1992, United States Strategic Command took over the Looking Glass mission from the Strategic Air Command, as SAC was disbanded and Strategic Command assumed the nuclear deterrence mission.
Rhodanese is a mitochondrial enzyme that detoxifies cyanide (CN−) by converting it to thiocyanate (SCN−, also known as "rhodanate"). In enzymatology, the common name is listed as thiosulfate sulfurtransferase (EC 2.8.1.1). It catalyzes the following reaction:
Sources: en.wikipedia.org
== External links == "Food Packaging -- Roles, Materials, and Environmental Issues - IFT.org". www.ift.org. Retrieved 3 December 2018. Poly(hydroxyalkanoates) for Food Packaging: Application and Attempts towards Implementation
=== Privatisation === In 1994, the Commonwealth facility was privatised by the Keating government as CSL Ltd. and was publicly listed and traded on the Australian Securities Exchange. The company completed an initial public offering in June 1994 at A$2.30 per share (76.7c adjusted for split). CSL stock is part of the S&P/ASX 20 Index.
=== Etymology === Ayahuasca is the hispanicized spelling (i.e., spelled according to Spanish orthography) of a word that originates from the Quechuan languages, which are spoken in the Andean states of Ecuador, Bolivia, Peru, and Colombia. Speakers of Quechuan languages who use modern Quechuan orthography spell it ayawaska. The word refers both to the liana Banisteriopsis caapi, and to the brew prepared from it. In the Quechuan languages, aya means 'spirit, soul', or 'corpse, dead body', and waska means 'rope' or 'woody vine, liana'. The word ayahuasca has been variously translated as 'liana of the soul', 'liana of the dead', and 'spirit liana'. In the cosmovision of its users, the ayahuasca is the vine that allows the spirit to wander detached from the body, entering the spiritual world, otherwise forbidden for the alive.
Sources: en.wikipedia.org
RNAP initiates transcription of the trp promoter. RNAP pauses at about nucleotide 90 at a secondary structure (?the first one shown above?). Ribosomes engage this nascent mRNA and initiate translation of the leader peptide. RNAP is then "released" from its pause and continues transcription. When RNAP reaches the region of the potential terminator, whether it continues or not is dependent on the position of the ribosome "trailing behind". If the ribosome stalls at the tandem Trp codons, waiting for the appropriate tRNA, region 1 is sequestered within the ribosome and thus cannot base pair with region 2. This means that region 2 and 3 become based paired before region 4 can be transcribed. This forces region 4 when it is made to be single stranded, preventing the formation of the region 3/4 terminator structure. Transcription will then continue. If the ribosome translates the leader peptide with no hesitation, it then covers a portion of region 2 preventing it from base pairing with region 3. Then when region 4 is transcribed, it forms a stem and loop with region 3 and transcription is terminated, generating a ca. 140 base transcript. This mechanism of control measures the amount of available, charged Trp-tRNA. The location of ribosomes determines which alternate secondary structures form.
Bone is a form of connective tissue found in the body, composed largely of hardened hydroxyapatite-containing collagen. In larger mammals, it is arranged in osteon regions. Bone matrix allows mineral salts such as calcium to be stored and provides protection for internal organs and support for locomotion.
In order to get a moist dentin, it is advisable to not dry dentin with compressed air after rinsing away the etchant. Instead, high volume evacuation suction can be used to remove excess water and then blot the remaining water present on dentin using gauze or cotton. The dentin surface should appear glistening. If the dentin surface is too wet, water will dilute the resin primer and compete for the sites in collagen network, which will prevent hybrid layer formation. If the dentin surface is too dry, collapse of collagen fibres and demineralized dentin can occur, leading to low bond strength.
=== 2006–2013: Rise to prominence and subsequent hiatus === Larter auditioned for the science fiction drama television series Heroes on NBC while living in Los Angeles. She played the characters of Niki Sanders, who suffered from dissociative identity disorder, and Tracy Strauss on the show created by Tim Kring. Larter's initial character Niki Sanders, was a wife, mother, and a former internet stripper from Las Vegas exhibiting superhuman strength and alternate personalities who go by the names of Jessica and Niki. "Ali read for the part and just owned it from the second she walked in," Kring said to the Chicago Tribune, "It was a very impressive audition." In the third and fourth seasons, Larter played the new character of Tracy Strauss, who possessed the ability to freeze objects and later, transform her body into water. Larter took on the title role in Marigold (2007), alongside Salman Khan, an Indian actor. The film was released in August 2007 and revolved around Marigold Lexington, an American actress (Larter) who goes to India and gets caught up in the exotic world of Bollywood. Filming took place in North India and London, commencing in June 2004. In an interview with the BBC, Larter remarked this role was "an opportunity to overcome my fear of singing and dancing because I have no professional training... I really focused on the character and loved this journey she went on and the experiences she had." She was paid a seven-figure salary for her part in the film.
Sources: en.wikipedia.org
Its sequence corresponds to the amino-terminal portion of prothymosin alpha, a larger protein present in many cell types. The isolated 28-residue peptide is a fragment of that protein rather than a separately encoded molecule, and laboratory material is produced by synthesis.
The single bridge between two cysteine residues holds the chain in a folded loop that influences its shape and its behavior in solution. Loss of the bridge through reduction or oxidation shifts chromatographic retention and is tracked during stability work.
It is a defined 28-residue sequence derived from a larger precursor, whereas many other thymic preparations are mixtures of several polypeptides. Its acetylated amino terminus and single disulfide bridge distinguish it chemically from unrelated thymic extracts.
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.