Everything below concerns thymalfasin. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-04-20. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| 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 |
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.
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.
There are also many overseas British independent schools in Hong Kong, such as Harrow International School Hong Kong, where 94% of students received grade (A*-B), Wycombe Abbey School Hong Kong, Malvern College Hong Kong, and Shrewsbury International School Hong Kong. Moreover, many schools cover various regions of the world, such as Australian International School, American International School, Canadian International School, French International School, and Korean International School among others. Local schools in Hong Kong are categorized into three "bands" based on academic performance, with Band 1 schools being the most prestigious and competitive. These institutions are often criticized for being high-pressure environments. Band 1 schools include Diocesan Boys' School, Diocesan Girls' School, Ying Wa College, St. Paul's College and La Salle College.
=== Absorbance for non-scattering samples === Within a homogeneous medium such as a solution, there is no scattering. In this case, researched extensively by August Beer, the concentration of the absorbing species follows the same linear contribution to absorbance as the path-length. Additionally, the contributions of individual absorbing species are additive. This is a very favorable situation, and made absorbance an absorption metric far preferable to absorption fraction (absorptance). This is the case for which the term "absorbance" was first used. A common expression of the Beer's law relates the attenuation of light in a material as
== Limitations == Nasal administration is primarily suitable for potent drugs since only a limited volume can be sprayed into the nasal cavity. Drugs for continuous and frequent administration may be less suitable because of the risk of harmful long-term effects on the nasal epithelium. Nasal administration has also been associated with a high variability in the amount of drug absorbed. Upper airway infections may increase the variability as may the extent of sensory irritation of the nasal mucosa, differences in the amount of liquid spray that is swallowed and not kept in the nasal cavity and differences in the spray actuation process. However, the variability in the amount absorbed after nasal administration should be comparable to that after oral administration.
Sources: en.wikipedia.org
Chemical principles govern specific RNA interaction with amino acids. Experiments with aptamers showed that some amino acids have a selective chemical affinity for their codons. Experiments showed that of 8 amino acids tested, 6 show some RNA triplet-amino acid association. Biosynthetic expansion. The genetic code grew from a simpler earlier code through a process of "biosynthetic expansion". Primordial life "discovered" new amino acids (for example, as by-products of metabolism) and later incorporated some of these into the machinery of genetic coding. Although much circumstantial evidence has been found to suggest that fewer amino acid types were used in the past, precise and detailed hypotheses about which amino acids entered the code in what order are controversial. However, several studies have suggested that Gly, Ala, Asp, Val, Ser, Pro, Glu, Leu, Thr may belong to a group of early-addition amino acids, whereas Cys, Met, Tyr, Trp, His, Phe may belong to a group of later-addition amino acids. An alternative analysis of amino acid usage in the Last Universal Common Ancestor concluded that the amino acids came in the following order: Val, Gly, Ile, Met, Ala, Thr, His, Glu, Cys, Pro, Lys, Ser, Asp, Leu, Asn, Arg, Phe, Tyr, Gln, Trp.
Due to competition, the early 1980s recession, the early 1990s recession, and lost focus, the company's growth stalled in the 1980s and early 1990s. D’Arbeloff, the chairman of the company, died of cancer and the COO and CTO died in a helicopter crash while commuting between facilities. The anticipated synergies never materialized. In 1994, an investor group led by management purchased the company for $360 million. That year, the company introduced Symmetry HPLC columns. It had a renewed focus for growth under CEO Douglas A. Berthiaume. Pharmaceutical spending also increased after the failure of the Clinton health care plan of 1993. In November 1995, the company once again became a public company via an initial public offering. In 1996, in addition to acquiring TA Instruments, it introduced the Alliance HPLC system. The following year, Waters acquired Micromass for $176 million, entering the mass spectrometry market. In 2004, the company introduced the Acquity UPLC system, which brought greater speed, resolution, and sensitivity to chromatographic separations and was considered a breakthrough technology. In 2006, Waters acquired Vicam, provider of bio-separation and rapid detection products for improving food safety and quality. In January 2020, it acquired Andrew Alliance, a producer of software and robotics for laboratory automation, for $77.4 million. In September, Udit Batra was named President and Chief Executive Officer of the company. In May 2023, Waters acquired Wyatt Technology for $1.36 billion in cash.
Inuktitut is the majority language in Nunavut and is one of three official languages in the territory. As of the 2021 census, just over 7.8 million Canadians listed a non-official language as their first language. Some of the most common non-official first languages include Mandarin (679,255 first-language speakers), Punjabi (666,585), Cantonese (553,380), Spanish (538,870), Arabic (508,410), Tagalog (461,150), Italian (319,505), German (272,865), and Tamil (237,890). The country is also home to many sign languages, some of which are Indigenous. American Sign Language (ASL) is used across the country due to the prevalence of ASL in primary and secondary schools. Quebec Sign Language (LSQ) is used primarily in Quebec.
Some of the earliest plastics were based on casein. In particular, galalith was well known for use in buttons. Milk fiber can be made from extruded casein. Lanital, a fabric made from casein fiber (known as Aralac in the United States), was invented in Italy in 1935. This material, also referred to as milk cotton, is used in yarn production and can be made from a blend of casein and acrylonitrile, or in some cases, from pure casein.
Sources: en.wikipedia.org
== In nature == Numerous biomolecules exhibit the ability to dissolve certain metal cations. Thus, proteins, polysaccharides, and polynucleic acids are excellent polydentate ligands for many metal ions. Organic compounds such as the amino acids glutamic acid and histidine, organic diacids such as malate, and polypeptides such as phytochelatin are also typical chelators. In addition to these adventitious chelators, several biomolecules are specifically produced to bind certain metals (see next section). Virtually all metalloenzymes feature metals that are chelated, usually to peptides or cofactors and prosthetic groups. Such chelating agents include the porphyrin rings in hemoglobin and chlorophyll. Many microbial species produce water-soluble pigments that serve as chelating agents, termed siderophores. For example, species of Pseudomonas are known to secrete pyochelin and pyoverdine that bind iron. Enterobactin, produced by E. coli, is the strongest chelating agent known. The marine mussels use metal chelation, especially Fe3+ chelation with the Dopa residues in mussel foot protein-1 to improve the strength of the threads that they use to secure themselves to surfaces. In earth science, chemical weathering is attributed to organic chelating agents (e.g., peptides and sugars) that extract metal ions from minerals and rocks. Most metal complexes in the environment and in nature are bound in some form of chelate ring (e.g., with a humic acid or a protein).
=== EC 1.3.99 With unknown physiological acceptors === EC 1.3.99.1: The activity is included in EC 1.3.5.1, succinate dehydrogenase (quinone) EC 1.3.99.2: Now EC 1.3.8.1, butyryl-CoA dehydrogenase. EC 1.3.99.3: now EC 1.3.8.7, medium-chain acyl-CoA dehydrogenase, EC 1.3.8.8, long-chain acyl-CoA dehydrogenase and EC 1.3.8.9, very-long-chain acyl-CoA dehydrogenase EC 1.3.99.4: 3-oxosteroid 1-dehydrogenase EC 1.3.99.5: 3-oxo-5α-steroid 4-dehydrogenase (acceptor) EC 1.3.99.6: 3-oxo-5β-steroid 4-dehydrogenase EC 1.3.99.7: Now EC 1.3.8.6, glutaryl-CoA dehydrogenase EC 1.3.99.8: 2-furoyl-CoA dehydrogenase EC 1.3.99.9: Now EC 1.21.99.1, β-cyclopiazonate dehydrogenase EC 1.3.99.10: Now EC 1.3.8.4, isovaleryl-CoA dehydrogenase EC 1.3.99.11: transferred to EC 1.3.5.2, dihydroorotate dehydrogenase EC 1.3.99.12: Now classified as EC 1.3.8.5, 2-methyl-branched-chain-enoyl-CoA reductase EC 1.3.99.13: Now EC 1.3.8.8, long-chain-acyl-CoA dehydrogenase EC 1.3.99.14: cyclohexanone dehydrogenase EC 1.3.99.15: Now EC 1.3.7.8 EC 1.3.99.16: isoquinoline 1-oxidoreductase EC 1.3.99.17: quinoline 2-oxidoreductase EC 1.3.99.18: quinaldate 4-oxidoreductase EC 1.3.99.19: quinoline-4-carboxylate 2-oxidoreductase EC 1.3.99.20: Now EC 1.3.7.9, 4-hydroxybenzoyl-CoA reductase EC 1.3.99.21: Now EC 1.3.8.3, (R)-benzylsuccinyl-CoA dehydrogenase EC 1.3.99.22: Now EC 1.3.98.3, coproporphyrinogen dehydrogenase EC 1.3.99.23: all-trans-retinol 13,14-reductase EC 1.3.99.24: Now EC 1.3.8.16, 2-amino-4-deoxychorismate dehydrogenase EC 1.3.99.25: carvone reductase EC 1.3.99.26: all-trans-ζ-carotene desaturase EC 1.3.99.27: 1-hydroxycarotenoid 3,4-desaturase EC 1.3.99.28: phytoene desaturase (neurosporene-forming) EC 1.3.99.29: phytoene desaturase (zeta-carotene-forming) EC 1.3.99.30: phytoene desaturase (3,4-didehydrolycopene-forming) EC 1.3.99.31: phytoene desaturase (lycopene-forming) EC 1.3.99.32: glutaryl-CoA dehydrogenase (non-decarboxylating) EC 1.3.99.33: urocanate reductase EC 1.3.99.34: Now classified as EC 1.3.7.11, 2,3-bis-O-geranylgeranyl-sn-glycero-phospholipid reductase EC 1.3.99.35: Now EC 1.3.7.15, chlorophyllide a reductase * EC 1.3.99.36: cypemycin cysteine dehydrogenase (decarboxylating) EC 1.3.99.37: 1-hydroxy-2-isopentenylcarotenoid 3,4-desaturase EC 1.3.99.38: menaquinone-9 β-reductase EC 1.3.99.39: carotenoid φ-ring synthase EC 1.3.99.40: carotenoid χ-ring synthase
Integrative Biology 131: General Human Anatomy (Fall 2005) by Professor Marian Diamond. Complete videos of the 40 lectures at Anatomy & Physiology (UC-Berkeley) "Anatomy of the Human Body". 20th edition. 1918. Henry Gray. In public domain. Human anatomy in photo Terminologia Anatomica (names of anatomical features) on FIPAT site
== Clinical signs == Horses with Type 1 PSSM usually appear normal at rest, but show signs of exertional rhabdomyolysis ("tying up") such as shortened stride, stiffness, firm musculature, sweating, pain or reluctance to exercise, when asked to perform light work. While episodes of exertional rhabdomyolysis is one of the most frequent signs associated with affected horses (reported in ~37% of affected animals), other common signs include gait abnormalities, shifting lameness, muscle weakness that may result in an inability to rise, colic-like pain, and muscle fasciculation, atrophy, and/or stiffness (most commonly seen in the semimembranosus, semitendinosus, and longissimus muscles). These clinical signs usually first become apparent when the horse is placed into training as a young animal; however, affected horses will show histological changes consistent with muscle damage at one month of age, and may also show elevations in creatine kinase (CK), an enzyme that elevates with muscle damage. Concurrent illness, such as respiratory or gastrointestinal infection, can lead to elevations in CK and potentially life-threatening rhabdomyolysis, even without exercise. Horses with PSSM often have a persistently elevated CK at rest, which differentiates the disease from recurrent exertional rhabdomyolysis, in which horses have normal CK concentrations between episodes.
Rosenthal, Anne M. (12 February 2003). "Murchison's Amino Acids: Tainted Evidence?". Astrobiology Magazine. Archived from the original on 30 August 2004. Matson, John (15 February 2010). "Meteorite That Fell in 1969 Still Revealing Secrets of the Early Solar System". Scientific American. This article incorporates public domain material from websites or documents of the National Aeronautics and Space Administration.
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.