This is a working overview of thymic extract, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-13 and is reviewed periodically as new material appears.
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 activity of this peptide is generally described as immunomodulatory rather than directly antimicrobial. Experimental work links it to signaling through certain Toll-like receptors on dendritic cells and to downstream maturation of antigen-presenting cells. Reported effects include expansion of T cell subsets, shifts in cytokine profiles, and increased natural killer cell activity. These observations come largely from cell culture and animal models, and the precise receptor-level events in humans remain incompletely characterized.
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.
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.
| 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 |
Storage recommendations center on low temperature, dryness, and protection from repeated freezing and thawing. The intact powder is commonly held at 20 degrees below zero Celsius or colder, while a working solution is divided into single-use aliquots to limit freeze-thaw cycles. Buffered saline or phosphate-buffered saline at neutral pH is frequently used as a diluent. Light sensitivity is not well documented, yet amber vials or foil wrapping are common practice for long-term storage of peptide stocks.
Identity and purity are assessed with a small set of standard peptide methods. Reversed-phase high-performance liquid chromatography separates the main peak from truncated or oxidized species, and its area percentage is the usual purity measure. Mass spectrometry confirms the observed molecular mass against the expected value, while amino acid analysis or peptide mapping checks composition and sequence. Specifications for research-grade material are often stated as 95 percent or higher, though the exact limit depends on the supplier and the intended use.
Laboratory supplies of the peptide usually arrive as a lyophilized powder in sealed vials. The powder is hygroscopic, so a vial should be allowed to reach room temperature before it is opened to prevent condensation on the contents. Weighing and transfer are best performed in a low-humidity environment with clean tools. Once dissolved, the solution should be mixed gently rather than vortexed, because foaming and shear can reduce recovery of the peptide.
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。
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。
Thymosin alpha 1 is a 28-amino-acid peptide first isolated from thymosin fraction 5, a bovine thymic extract. Its sequence begins with an acetylated serine residue and carries a high proportion of acidic residues, so the molecule has a net negative charge near neutral pH. Despite the shared name, it is unrelated in sequence to the thymosin beta family. Synthetic material prepared by solid-phase peptide synthesis is identical in sequence to the natural peptide.
Several names appear in the literature for this peptide, including thymalfasin and the abbreviation T-alpha-1. Naming conventions differ among research articles, regulatory documents, and supplier catalogs, which complicates literature searches. Both synthetic and recombinant production routes yield a peptide with the same 28-residue sequence as the thymic isolate. Because the thymosin label also covers unrelated peptides, sources should be compared by sequence rather than by name alone.
The peptide occurs naturally in thymic tissue and has been detected in serum and other biological fluids. Reported concentrations are low, and reliable measurement generally requires immunoassay or mass spectrometry with an enrichment step. It is released from a larger precursor, prothymosin alpha, by proteolytic cleavage, although the enzymes involved are not fully characterized. Whether circulating levels reflect thymic output specifically remains an open question.
Collective cell migration is studied over many model species. Border cells in flies (Drosophila melanogaster): the border cells migrate during the differentiation of egg cells to be ready for fertilization. The lateral line in zebrafish: collective cell migration from head to tails is essential to the development of the sensory system of the fish. The sensors of the lateral line measure the flow over the body-surface of the fish. Wound healing: collective cell migration is an essential part in this healing process, wound area is closed by the migrating cells. Wound healing is commonly studied in vitro using cell lines such as Madin-Darby Canine Kidney cells. Neural crest cells in mice, Leghorn chicks, amphibians (Xenopus laevis), and fish (zebrafish): collective migration of neural crest cells occurs during embryo development of vertebrates. They migrate long distances from the head (neural tube) to give rise to different tissues. Spreading of cancer (metastasis): common complication of cancer involve formation of new tumors (secondary tumors), as a result of migration of cancer cells from the primary tumor. Similar to collective cell migration in development and wound healing, cancer cells also undergo epithelial to mesenchymal transition (EMT), that reduces cell-cell adhesions and allows cancer spreading. The diagram on the right shows:
ADP + phosphate + NADPH In humans, this enzyme is encoded by the gene NAXD. This enzyme belongs to the family of lyases, specifically the hydro-lyases, which cleave carbon-oxygen bonds. The systematic name of this enzyme class is (6S)-6-β-hydroxy-1,4,5,6-tetrahydronicotinamide-adenine-dinucleotide hydro-lyase (ATP-hydrolysing; NADH-forming). Other names in common use include reduced nicotinamide adenine dinucleotide hydrate dehydratase, ATP-dependent H4NAD(P)+OH dehydratase, (6S)-β-6-hydroxy-1,4,5,6-tetrahydronicotinamide-adenine-, and dinucleotide hydro-lyase (ATP-hydrolysing).
The origin of the hydrophobic effect is not fully understood. Some argue that the hydrophobic interaction is mostly an entropic effect originating from the disruption of highly dynamic hydrogen bonds between molecules of liquid water by the nonpolar solute. A hydrocarbon chain or a similar nonpolar region of a large molecule is incapable of forming hydrogen bonds with water. Introduction of such a non-hydrogen bonding surface into water causes disruption of the hydrogen bonding network between water molecules. The hydrogen bonds are reoriented tangentially to such surface to minimize disruption of the hydrogen bonded 3D network of water molecules, and this leads to a structured water "cage" around the nonpolar surface. The water molecules that form the "cage" (or clathrate) have restricted mobility. In the solvation shell of small nonpolar particles, the restriction amounts to some 10%. For example, in the case of dissolved xenon at room temperature a mobility restriction of 30% has been found. In the case of larger nonpolar molecules, the reorientational and translational motion of the water molecules in the solvation shell may be restricted by a factor of two to four; thus, at 25 °C the reorientational correlation time of water increases from 2 to 4-8 picoseconds. Generally, this leads to significant losses in translational and rotational entropy of water molecules and makes the process unfavorable in terms of the free energy in the system. By aggregating together, nonpolar molecules reduce the surface area exposed to water and minimize their disruptive effect.
Sources: en.wikipedia.org
=== Aneuploidy === Sex chromosomes Analysis of maternal serum cffDNA by high-throughput sequencing can detect common fetal sex chromosome aneuploidies such as Turner's syndrome, Klinefelter's syndrome and triple X syndrome but the procedure's positive predictive value is low.
== See also == Collective intelligence Futurists Internet think tanks List of think tanks List of think tanks in the United States Lobbying Mass collaboration Mass communication Overton window School of thought Strategic studies TED (conference)
== External links == Overview of Colombian–FARC Peace Process Who are the victims? – The aftermath of violence in Colombia – (Former combatants in Colombia's internal armed conflict spent two years painting their experiences. They face difficult decisions about what to remember, what to forget and how to forgive) "Colombia Page on InSight Crime". Archived from the original on July 26, 2011. Retrieved March 29, 2011. (Ongoing reporting on the Colombian conflict and active criminal groups) "Evolution of the Colombian Civil War". Paul Wolf. Archived from the original on February 3, 2006. Retrieved February 24, 2006. (collection of declassified U.S. documents online) Michael Evans, ed. (May 3, 2002). "War in Colombia: Guerrillas, Drugs and Human Rights in U.S.-Colombia Policy, 1988–2002". National Security Archive Electronic Briefing Book No. 69. National Security Archive. "America's Other War: Terrorizing Colombia". Retrieved February 25, 2006.{{cite web}}: CS1 maint: deprecated archival service (link) Plan Colombia by Carmen Guhn-Knight "Rule of Law in Armed Conflict: Colombia". RULAC Project. Archived from the original on July 6, 2011. Retrieved March 23, 2009. "Q&A: Colombia's civil conflict". BBC News. December 23, 2009. Retrieved February 24, 2006. "Colombia Program". Center for International Policy. Retrieved February 24, 2006. "Accord issue on Colombia's peace process". Alternatives to war. Archived from the original on November 17, 2006. Retrieved November 18, 2006. (In Spanish and English with chronology and key texts and agreements) "CERAC".
== Principle in medical diagnostics == Glycation of proteins is a frequent occurrence, but in the case of hemoglobin, a nonenzymatic condensation reaction occurs between glucose and the N-end of the beta chain. This reaction produces a Schiff base (R−N=CHR', R=beta chain, CHR'=glucose-derived), which is itself converted to 1-deoxyfructose. This second conversion is an example of an Amadori rearrangement. When blood glucose levels are high, glucose molecules attach to the hemoglobin in red blood cells. The longer hyperglycemia occurs in blood, the more glucose binds to hemoglobin in the red blood cells and the higher the glycated hemoglobin. Once a hemoglobin molecule is glycated, it remains that way. A buildup of glycated hemoglobin within the red cell, therefore, reflects the average level of glucose to which the cell has been exposed during its life cycle. Measuring glycated hemoglobin assesses the effectiveness of therapy by monitoring long-term serum glucose regulation. A1c is a weighted average of blood glucose levels during the life of the red blood cells (117 days for men and 106 days in women). Therefore, glucose levels on days nearer to the test contribute substantially more to the level of A1c than the levels on days further from the test. This is also supported by data from clinical practice showing that HbA1c levels improved significantly after 20 days from the start or intensification of glucose-lowering treatment.
Sources: en.wikipedia.org
The direct gating or opening of the chloride ion channel is the reason for the increased toxicity of barbiturates compared to benzodiazepines in overdose. Further, barbiturates are relatively non-selective compounds that bind to an entire superfamily of ligand-gated ion channels, of which the GABAA receptor channel is only one of several representatives. This Cys-loop receptor superfamily of ion channels includes the neuronal nACh receptor channel, the 5-HT3 receptor channel, and the glycine receptor channel. However, while GABAA receptor currents are increased by barbiturates (and other general anesthetics), ligand-gated ion channels that are predominantly permeable for cationic ions are blocked by these compounds. For example, neuronal nAChR channels are blocked by clinically relevant anesthetic concentrations of both thiopental and pentobarbital. Such findings implicate (non-GABA-ergic) ligand-gated ion channels, e.g. the neuronal nAChR channel, in mediating some of the (side) effects of barbiturates. This is the mechanism responsible for the (mild to moderate) anesthetic effect of barbiturates in high doses when used in anesthetic concentration.
On 3 April, Ruthaphon Naowarat, Minister of Justice, stated in CCSA Press Conference that the Ministry of Justice had detected 57 million litres of fuel missing from 217 million litres transported by sea to six oil depots in Surat Thani province, only 160 million litres arrived at destination. This has created controversies regarding government responsibilities. On 4 April, Bangchak Corporation, the third largest oil company in Thailand with around 2200 petrol stations nationwide, announced the "Fry to Fly" Program, which offers customers to exchange 2 litres of used cooking oil for 1 litre of diesel fuel or petrol (up to 20 litres of cooking oil per person) at 15 stations across the Bangkok Metropolitan Region. This program reduces customers' fuel costs and allows Bangchak to use the used cooking oil to produce sustainable aviation fuel (SAF). The program will be in effect from 6 to 30 April. On 8 April, the Energy Policy Administration Committee announced on the Royal Gazette of Thailand that diesel prices would be cut at the refinery level by 2 THB per litre, aiming to reduce fuel costs and cost of living for Thai citizens. This reduction includes Diesel B0, Diesel B7 and Diesel B20 blends, effective from 9 April. This resulted in diesel fuel prices dropping from 50.54 THB per litre on 7 April, to 48.40 THB per litre on 9 April. On 11 April prices dropped to 44.40 THB per litre for normal diesel and to 37.40 THB per litre for Diesel B20.
Veins below the skin can appear blue or green due to subsurface scattering of light through the skin, and aspects of human color perception. Many medical diagrams also use blue to show veins, and red to show arteries, which contributes to this misconception. Asystole, also known as a "flatline", is not a shockable rhythm and is neither treated nor cured via defibrillation. Medical interventions for asystole include high-quality CPR and (in a medically professional environment) epinephrine administration. The misconception may stem from outdated medical practices and Hollywood glamorization of resuscitation efforts. Exposure to a vacuum, or experiencing all but the most extreme uncontrolled decompression, does not cause the body to explode or internal fluids to boil (although the fluids in the mouth and lungs will indeed boil at altitudes above the Armstrong limit); rather, it will lead to a loss of consciousness once the body has depleted the supply of oxygen in the blood, followed by death from hypoxia within minutes. Exercise-induced delayed onset muscle soreness is not caused by lactic acid build-up. Muscular lactic acid levels return to normal levels within an hour after exercise; delayed onset muscle soreness is thought to be due to microtrauma from unaccustomed or strenuous exercise. Stretching before or after exercise does not reduce delayed onset muscle soreness. Urine is not sterile, not even in the bladder. This misconception may derive from urine bacterial screening tests, which return "negative" when bacteria levels are low, but nonzero.
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.
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.