If you have been reading about thymus extract 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.
Updated 2025-10-26. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Immunological studies connect the peptide to multiple parts of the immune response. It has been reported to engage Toll-like receptor signaling, to promote dendritic cell maturation, and to influence the balance of T helper cell subsets. Changes in natural killer cell activity and in cytokine release appear in cell culture and animal models. These observations describe broad immunomodulatory behavior rather than a single defined receptor target, and the primary molecular interaction has not been settled.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic peptide, 28 residues | N-terminal fragment of prothymosin alpha |
| Molecular mass | About 3108 Da | Acetylated form |
| Isoelectric point | Near 4.2 | Acidic peptide |
| Appearance | White to off-white lyophilized powder | Common supplied form |
| Typical storage | -20 °C or below, dry | Solution stability is lower |
20世纪70年代，研究者从胸腺提取物中纯化出多种小肽，Tα1是其中被较早表征的一种。最初的制备依赖组织匀浆和层析步骤，产量低且成分复杂。随着固相肽合成技术成熟，实验室和工业界能够生产与天然序列一致的合成版本。合成肽的纯度可达95%以上，并可通过反相高效液相色谱和质谱进行鉴定。这一转变使研究不再依赖动物胸腺来源。
市售的胸腺素α1通常以冻干粉形式提供，溶解后用于注射。其氨基酸组成包括多个酸性残基，因此在中性pH下带负电荷。该肽可溶于水和生理盐水，但在有机溶剂中溶解度有限。储存条件通常为冻干状态下负20摄氏度，溶解后需冷藏并避免反复冻融。常见的同义词包括胸腺肽α1、thymalfasin和Tα1。
胸腺素α1（thymosin alpha 1，Tα1）是一种由28个氨基酸组成的酸性肽，N端被乙酰化，分子量约为3108道尔顿。该肽最早从牛胸腺组织提取物中分离，属于胸腺素组分5的一个成分。其序列在不同哺乳动物中高度保守，提示其具有基本的生物学功能。名称中的“α1”指其在电泳中的迁移位置，并非表示亚型编号。它既存在于胸腺，也存在于脾脏和淋巴结等免疫组织。
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.
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.
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.
Most published studies on thymosin alpha-1 report changes in immune measurements rather than clinical outcomes, and findings differ across designs and populations. Whether the peptide signals through one defined receptor or through several less specific interactions remains an open question. Its reported circulation half-life of a few hours complicates comparison of dosing schedules across trials. Mechanistic claims are frequently drawn from isolated cell cultures, and how far those results extend to whole organisms is unresolved.
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.
Initially, PKCε was thought to protect mitochondria from MPT through its association with VDAC1, ANT, and hexokinase II; however, genetic studies have since ruled this out and subsequent studies have identified the F0/F1 ATP synthase as a core inner mitochondrial membrane component and Bax and Bak as potential outer membrane components These findings have opened up new avenues of investigation for the role of PKCε at mitochondria. Several likely targets of PKCε action affecting MPT have been discovered. PKCε interacts with ERK, JNKs and p38, and PKCε directly or indirectly phosphorylates ERK and subsequently Bad. PKCε also interacts with Bax in cancer cells, and PKCε modulates its dimerization and function. Activation of PKCε with the specific activator, εRACK, prior to ischemic injury has shown to be associated with phosphorylation of the F0/F1 ATP synthase. Moreover, the modulatory component, ANT is regulated by PKCε. These data suggest that PKCε may act at multiple modulatory targets of MPT function; further studies are required to unveil the specific mechanism.
=== Self-efficacy === Self-efficacy refers to a belief that one's ability to accomplish a task is a function of personal effort. Low self-efficacy, or a disconnect between ability and personal effort, is associated with depression; by comparison, high self-efficacy is associated with positive change, including overcoming abuse, overcoming eating disorders, and maintaining a healthy lifestyle. High self-efficacy also has positive benefits for one's immune system, aids in stress management, and decreases pain. A related concept, Personal effectiveness, is primarily concerned with planning and the implementation of methods of accomplishment.
Tyrosine hydroxylase catalyzes the reaction in which L-tyrosine is hydroxylated in the meta position to obtain L-3,4-dihydroxyphenylalanine (L-DOPA). The enzyme is an oxygenase which means it uses molecular oxygen to hydroxylate its substrates. One of the oxygen atoms in O2 is used to hydroxylate the tyrosine molecule to obtain L-DOPA and the other one is used to hydroxylate the cofactor. Like the other aromatic amino acid hydroxylases (AAAHs), tyrosine hydroxylase use the cofactor tetrahydrobiopterin (BH4) under normal conditions, although other similar molecules may also work as a cofactor for tyrosine hydroxylase. The AAAHs converts the cofactor 5,6,7,8-tetrahydrobiopterin (BH4) into tetrahydrobiopterin-4a-carbinolamine (4a-BH4). Under physiological conditions, 4a-BH4 is dehydrated to quinonoid-dihydrobiopterin (q-BH2) by the enzyme pterin-4a-carbinolamine dehydrase (PCD) and a water molecule is released in this reaction. Then, the NAD(P)H dependent enzyme dihydropteridine reductase (DHPR) converts q-BH2 back to BH4. Each of the four subunits in tyrosine hydroxylase is coordinated with an iron(II) atom presented in the active site. The oxidation state of this iron atom is important for the catalytic turnover in the enzymatic reaction. If the iron is oxidized to Fe(III), the enzyme is inactivated. The product of the enzymatic reaction, L-DOPA, can be transformed to dopamine by the enzyme DOPA decarboxylase.
Contrail, also known as vapor trail – Long, thin artificial clouds that sometimes form behind aircraft Dilution (equation) – Chemistry concept Evaporation – Vaporization of a liquid from its surface Henry's law – Gas law regarding proportionality of dissolved gas Vaporizer (disambiguation)
S-adenosyl-L-methionine = 1-aminocyclopropane-1-carboxylate + S-methyl-5′-thioadenosine Like other PLP dependent enzymes, it catalyzes the reaction through a quinonoid zwitterion intermediate and uses cofactor pyridoxal phosphate (PLP, the active form of vitamin B6) for stabilization. This enzyme belongs to the family of lyases, specifically carbon-sulfur lyases. The systematic name of this enzyme class is S-adenosyl-L-methionine S-methyl-5′-thioadenosine-lyase (1-aminocyclopropane-1-carboxylate-forming). Other names in common use include 1-aminocyclopropanecarboxylate synthase, 1-aminocyclopropane-1-carboxylic acid synthase, 1-aminocyclopropane-1-carboxylate synthetase, aminocyclopropanecarboxylic acid synthase, aminocyclopropanecarboxylate synthase, ACC synthase, and S-adenosyl-L-methionine methylthioadenosine-lyase. This enzyme participates in propanoate metabolism. It employs one cofactor, pyridoxal phosphate.
Sources: en.wikipedia.org
Two different kinds of blank may be measured: a sample of dead carbon that has undergone no chemical processing, to detect any machine background, and a sample known as a process blank made from dead carbon that is processed into target material in exactly the same way as the sample which is being dated. Any 14C signal from the machine background blank is likely to be caused either by beams of ions that have not followed the expected path inside the detector or by carbon hydrides such as 12CH2 or 13CH. A 14C signal from the process blank measures the amount of contamination introduced during the preparation of the sample. These measurements are used in the subsequent calculation of the age of the sample.
=== Linus Pauling and the molecular clock hypothesis === Zuckerkandl's first project under Pauling (working with graduate student Richard T. Jones) was the application of new protein identification techniques—a combination of paper chromatography and electrophoresis that produced a two-dimensional pattern—to hemoglobin. The peptide fragments of hemoglobin samples from different species, partially broken apart by digestive enzymes, would produce unique patterns that could be used to estimate differences of protein structure. Zuckerkandl, Jones and Pauling published a comparison of several species' hemoglobin identification patterns in 1960, observing that the degree of dissimilarity of protein patterns corresponded approximately to the phylogenetic distance between source species. However, the method was not conducive to quantitative comparisons, so Zuckerkandl began working on the determination of the actual peptide sequence of the α and β chains of human and gorilla hemoglobin. In 1962, Pauling and Zuckerkandl published their first paper using the molecular clock concept (though not yet by that name). Like a number subsequent collaborative papers, it was not peer-reviewed—it was an invited paper in honor of Albert Szent-Györgyi—and they intentionally took the opportunity to "say something outrageous". The paper used the number of differences in the α and β chains of hemoglobin to infer the time since the last common ancestor for a number of species, calibrated based on paleontological evidence for humans and horses.
In 2016, Burger King signed a build-to-suit lease agreement on a new 150,000 square feet (14,000 m2) five-story headquarters building to be built at 5707 Blue Lagoon Drive, just down the street from its existing nine-story headquarters at 5505 Blue Lagoon Drive. This was slightly smaller than the 200,000 square feet (19,000 m2) it was leasing in its current headquarters building at the time. In 2018, Burger King moved into its new headquarters at 5707 Blue Lagoon Drive. As of August 2024, the Burger King system operates more than 18,700 locations in more than 100 countries and U.S. territories.
=== Nonalcoholic fatty liver disease === Supplemental vitamin E significantly reduced elevated liver enzymes, steatosis, inflammation and fibrosis, suggesting that the vitamin may be useful for treatment of nonalcoholic fatty liver disease (NAFLD) and the more extreme subset known as nonalcoholic steatohepatitis (NASH) in adults, but not in children.
Sources: en.wikipedia.org
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.
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.