Everything below concerns Immune modulation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-04-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Within the immune system, the peptide acts on several cell types rather than a single target. Reported activities include promotion of T-cell maturation, enhancement of natural killer cell activity, and modulation of cytokine production by dendritic cells and macrophages. Some of these effects appear to operate through toll-like receptor signaling, though the precise receptor-level mechanism remains debated. Whether the observed immune changes translate into clinical benefit is a separate question and depends on the indication studied.
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 formula | C129H215N33O55 | Calculated for the acetylated 28-residue peptide |
| Appearance | White to off-white powder | Lyophilized solid recovered from aqueous buffer |
| Solubility | Freely soluble in water | Typically dissolved in water or buffer before use |
| Typical storage | -20 C or below, desiccated | Protect from light and avoid repeated freeze-thaw cycles |
| Identity testing | Reverse-phase HPLC with mass spectrometry | Retention time and measured mass confirm the sequence |
Thymosin alpha-1 is supplied as a lyophilized powder in most research settings. The solid dissolves readily in water and in common aqueous buffers, and it is typically reconstituted shortly before use. Solutions are clear and colourless at ordinary working concentrations. Because the peptide is hygroscopic, weighing and reconstitution are usually performed with minimal exposure to ambient air. Aliquots are prepared to avoid repeated freeze-thaw cycles, and working solutions are kept cold.
Long-term storage is generally at minus twenty degrees Celsius or colder, preferably desiccated and protected from light. Lyophilized material is more stable than reconstituted solution, which degrades faster at room temperature. Stability depends on pH, ionic strength, and the presence of oxidising agents. Published stability data for the peptide are limited, so storage claims in catalogues should be treated as general guidance rather than measured guarantees. Freeze-thaw cycles are kept to a minimum.
Identity and purity are normally confirmed by reversed-phase high-performance liquid chromatography and mass spectrometry. The expected mass for the acetylated 28-residue peptide is close to 3108 daltons, and a mass shift indicates a modification or truncation. Peptide mapping after enzymatic digestion can resolve sequence-level questions. Counter-ion content, water content, and residual solvents are separate quality attributes that a certificate of analysis may or may not report. Aggregation is monitored by size-exclusion chromatography when relevant.
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.
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.
== Features == SENP1 (Sentrin-specific protease 1) is a human protease of 643 amino acids with a molecular weight of 73 kDa, EC number in humans 3.4.22.B70. It adopts a conformation that identifies it as a member of the superfamily of cysteine proteases, which contain a catalytic triad with three characterized amino acids: a cysteine at position 603, a histidine at position 533 and aspartic acid at position 550. The primary nucleophile is cysteine located at the N-terminal alpha helix of the protein core. The other two amino acids, aspartate and histidine, are located in the end of a beta sheet.
Endoxifen, also known as 4-hydroxy-N-desmethyltamoxifen, is a nonsteroidal selective estrogen receptor modulator (SERM) of the triphenylethylene group as well as a protein kinase C (PKC) inhibitor. It is under development for the treatment of estrogen receptor-positive breast cancer and for the treatment of mania in bipolar disorder. It is taken by mouth. Endoxifen is an active metabolite of tamoxifen and has been found to be effective in patients that have failed previous hormonal therapies (tamoxifen, aromatase inhibitors, and fulvestrant). The prodrug tamoxifen is metabolized by the CYP2D6 enzyme to produce endoxifen and afimoxifene (4-hydroxytamoxifen). Currently, endoxifen is approved by Drugs Controller General of India for the acute treatment of manic episode with or without mixed features of Bipolar I disorder. It is manufactured and sold by Intas Pharmaceuticals under the brand name Zonalta.
Semirational mutagenesis of a number of residues led to pH-sensitive mutants known as pHluorins, and later super-ecliptic pHluorins. By exploiting the rapid change in pH upon synaptic vesicle fusion, pHluorins tagged to synaptobrevin have been used to visualize synaptic activity in neurons. Redox sensitive GFP (roGFP) was engineered by introduction of cysteines into the beta barrel structure. The redox state of the cysteines determines the fluorescent properties of roGFP.
== Corrosion == Superheated water can be more corrosive than water at ordinary temperatures, and at temperatures above 300 °C special corrosion resistant alloys may be required, depending on other dissolved components. Continuous use of carbon steel pipes for 20 years at 282 °C has been reported without significant corrosion, and stainless steel cells showed only slight deterioration after 40–50 uses at temperatures up to 350 °C. The degree of corrosion that can be tolerated depends on the use, and even corrosion resistant alloys can fail eventually. Corrosion of an Inconel U-tube in a heat exchanger was blamed for an accident at a nuclear power station. Therefore, for occasional or experimental use, ordinary grades of stainless steel are probably adequate with continuous monitoring, but for critical applications and difficult to service parts, extra care needs to be taken in materials selection.
Sources: en.wikipedia.org
satisfying appropriate boundary conditions. Here, the projections are accomplished by the orthogonality of the solenoidal and irrotational function spaces. The discrete form of this is eminently suited to finite element computation of divergence-free flow, as we shall see in the next section. There, one will be able to address the question, "How does one specify pressure-driven (Poiseuille) problems with a pressureless governing equation?". The absence of pressure forces from the governing velocity equation demonstrates that the equation is not a dynamic one, but rather a kinematic equation where the divergence-free condition serves the role of a conservation equation. This would seem to refute the frequent statements that the incompressible pressure enforces the divergence-free condition.
On 7 December 2024, Syrian rebels announced that they had started surrounding Damascus after capturing nearby towns, with rebel commander Hassan Abdul Ghani stating: "Our forces have begun implementing the final phase of encircling the capital Damascus." The rebels started encircling the capital after capturing Al-Sanamayn, a town 20 kilometres (12 mi) from the southern entrance of Damascus. In the Rif Dimashq region, pro-government forces withdrew from the towns of Assal al-Ward, Yabroud, Flitah, Al-Naseriyah and Artouz, while rebels came within 10 kilometres (6.2 mi) of Damascus. The Syrian government denied claims that its army had withdrawn from positions near the city. By the evening, pro-government forces had left the towns on the outskirts of Damascus, including Jaramana, Qatana, Muadamiyat al-Sham, Darayya, Al-Kiswah, Al-Dumayr, Daraa and sites near the Mezzeh Air Base. Maher al-Assad and his 4th Division were reportedly among the few loyalists who still tried to defend the city; his second-in-command was later found dead in his office, possibly indicating violent disputes over the orders and escapes of many military officers. According to the Syrian Observatory for Human Rights, Syrian rebels were active in the Damascus suburbs of Jaramana, Muadamiyah, and Darayya, and were marching from the east toward Harasta. In the main square of Jaramana, protestors took down a statue of Hafez al-Assad. In the evening, pro-government forces reportedly withdrew from several suburbs where large-scale protests broke out.
=== Differentiation === CAFs can also be derived from differentiation of other cell types such as mesenchymal stem cells, which was proved in murine models with cancers such as glioma, breast, pancreatic and gastric cancers. Another suggested origin is differentiation of endothelial or epithelial cells via trans-differentiation or epithelial to mesenchymal transition, respectively. Less common origin of CAFs is by differentiation of other tumor adjacent cells such as epithelial or endothelial cells, adipocytes, pericytes and smooth muscle cells. Adipocytes, especially white adipocytes transdifferentiate into CAFs upon activation with TGF-β1. Through TGF-β1 can be transformed also peritoneal mesothelial cells. It has been suggested that CAFs are better conceptualised as a “cell state” Research has found that CAF trans-differentiation can be caused by epigenetic factors.
Sources: en.wikipedia.org
It is a 28-amino-acid peptide originally purified from a bovine thymic extract and later produced synthetically. It is studied mainly for its effects on immune cell function.
No. The two peptides share part of a name but differ in length, sequence, and net charge. Literature searches that treat them as one compound return misleading results.
Solid-phase peptide synthesis is the usual route, and recombinant expression has also been described. Both approaches produce material matching the natural sequence.
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.