This is a working overview of immunomodulatory peptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-04-06. Anything still debated is marked as such rather than presented as settled.
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.
Lyophilized material is typically treated as a hygroscopic solid that should be brought to room temperature before the container is opened, which limits condensation on the powder. Reconstitution is commonly done with sterile water or a buffered diluent, and gentle mixing is preferred over vigorous agitation to reduce foaming and surface adsorption. Because peptides can bind to plastic and glass, diluents containing a small amount of carrier protein are sometimes used in laboratory work. Working solutions are generally aliquoted and prepared fresh rather than subjected to repeated freezing and thawing.
Stability depends on temperature, pH, and the number of freeze-thaw events the sample has experienced. Freeze-dried material is commonly held at -20 °C or colder, while reconstituted liquid is kept cold and used within a short window. Extreme pH and prolonged light exposure can promote deamidation, oxidation, or aggregation, particularly at asparagine and methionine positions. Adsorption to container walls can lower the measured concentration of a dilute solution even when the peptide molecules themselves remain intact.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, which separates the target peptide from truncated or chemically modified byproducts. Mass spectrometry confirms the expected molecular mass and can indicate acetylation state or sequence errors. Amino acid analysis and peptide mapping supply complementary sequence-level information, while endotoxin testing is relevant for preparations intended for cell or animal work. Purity figures reported by suppliers refer to the method used and are not directly comparable across laboratories unless conditions are stated.
| 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 |
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.
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.
Like most short peptides, thymosin alpha-1 is susceptible to hydrolysis under strongly acidic or basic conditions and to oxidation when exposed to air over long periods. The acetylated amino terminus blocks one common degradation route, which contributes to the molecule's relative robustness in solution. Lyophilized material generally retains potency for extended periods when kept cold and dry. Once reconstituted, aqueous solutions are less stable and are typically used within a defined window rather than held indefinitely at ambient temperature.
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.
== Access == The library is open for academic research to anyone with a Reader Identification Card. One may not remove library items from the reading rooms or the library buildings. Most of the library's general collection of books and journals are in the closed stacks of the Jefferson and Adams Buildings; specialized collections of books and other materials are in closed stacks in all three main library buildings, or are stored off-site. Access to the closed stacks is not permitted under any circumstances, except to authorized library staff, and occasionally, to dignitaries. Only the reading room reference collections are on open shelves. Since 1902, American libraries have been able to request books and other items through interlibrary loan from the Library of Congress if these items are not readily available elsewhere. Through this system, the Library of Congress has served as a "library of last resort", according to Herbert Putnam, the librarian of Congress from 1899 to 1939. The Library of Congress lends books to other libraries with the stipulation that they be used only inside the borrowing library. In 2017, the Library of Congress began development on a reader's card for children under the age of sixteen.
The supply of PUFAs for ferroptosis also depends on glutaminolysis — the uptake of glutamine via membrane transporters SLC38A1 and SLC1A5, its conversion to α-ketoglutarate, and subsequent mitochondrial catabolism to generate acetyl-CoA for fatty acid synthesis. This process is regulated by AMP-activated protein kinase (AMPK), which plays a dual role in ferroptosis through phosphorylation of either Beclin-1 or acetyl-CoA carboxylase. Under stress conditions, lipid droplets can also release free fatty acids, further amplifying lipid peroxidation. Ferroptosis has been shown to involve distinct cellular organelles, which includes peroxisomes, mitochondria, the endoplasmic reticulum (ER) and lysosomes. It has been a debate in the scientific community as to where ferroptosis is initiated in the cell, and now research points to the lysosome, where the chemical environment (iron, pH an hydrogen peroxide) are favorable. Oxidation of phospholipids can occur when free radicals abstract electrons from a lipid molecule (typically affecting polyunsaturated fatty acids), thereby promoting their oxidation. The primary cellular mechanism of protection against ferroptosis is mediated by the selenoprotein GPX4, a glutathione-dependent hydroperoxidase that converts lipid hydroperoxides into non-toxic lipid alcohols. The abundant lipid soluble vitamin α-tocopherol complements GPX4 by acting as a radical-trapping antioxidant for lipid peroxyl radicals, the chief membrane damaging species in ferroptosis that cannot be reduced by GPX4.
=== Sexual dysfunction === Activation of 5-HT2C receptor subtype has been reported to mediate numerous effects, such as penile erection. Based on multiple studies, results show that several 5-HT2C receptor agonists, including mCPP and YM348 induce penile erections in rats, but mCPP seems to mimic both vasodilation and vasoconstriction. The vasodilator action is mediated by 5-HT1D receptors, whereas the vasoconstriction effect involves 5-HT2 receptor activation. YM-348 is a highly selective 5-HT2C agonist and results show that YM348 can induce penile erections and hypolocomotion (induced at a high dose) in rats, as did other 5-HT2C receptor agonists. These effects were completely inhibited by a selective 5-HT2C receptor antagonist, SB-242,084. Therefore, results suggest that YM348 is a potent and orally active 5-HT2C receptor agonist.
Sources: en.wikipedia.org
Gochujang's primary ingredients are red chili powder (고추가루; gochugaru), glutinous rice powder, powdered fermented soybeans, and salt. Korean chili peppers, of the species Capsicum annuum, are spicy yet sweet, making them ideal for gochujang production. Gochujang is typically made from 25% red pepper powder, 22.2% glutinous rice, 5.5% meju powder (60% cooked soybeans and 40% non-glutinous rice), 12.8% salt, 5% malt, and 29% water. Other recipes use glutinous rice (찹쌀; chapssal), normal short-grain rice (맵쌀; mepssal), or barley. Less common additions include whole wheat kernels, jujubes, pumpkin, and sweet potato. A small amount of sweetener, such as sugar, syrup, or honey, is also sometimes added. The finished product is a dark red paste, with a rich, piquant flavor. The making of gochujang at home began tapering off when commercial production came into the mass market in the early 1970s. Now, most Koreans purchase gochujang at grocery stores or markets. It is still used extensively in Korean cooking to flavor stews (jjigae), such as in gochujang jjigae; to marinate meat, such as in gochujang bulgogi; and as a condiment for naengmyeon and bibimbap. Gochujang is also used as a base for making other condiments, such as chogochujang (초고추장) and ssamjang (쌈장). Chogochujang is a variant of gochujang made by adding vinegar and other seasonings, such as sugar and sesame seeds. It is usually used as a sauce for hoe and hoedeopbap.
This formula was developed by Levey et al. The 2009 CKD-EPI formula was suggested to improve cardiovascular risk prediction over the MDRD Study formula in a middle-age population. The 2021 CKD-EPI formula does not include a race coefficient (see discussion below). The 2021 CKD-EPI equation is:
==== Hypothermia ==== On 16 January 2024, doctors reported children weakened by starvation were dying from hypothermia. An ActionAid coordinator stated on 27 January 2024 that children without winter coats were suffering from the cold and rainfall of the winter months, with new commercial products prevented from being brought in. An Al Jazeera correspondent reported he had witnessed children sleeping in cold, mud-filled tents. One father stated in an interview on 2 February 2024, " It’s so freezing. Even my children can’t. One to two blankets aren’t enough at all. I have a newborn baby. I fear he will be ill every other day." Children in Rafah were dressed in remaining PPE equipment from the COVID-19 pandemic in order to keep warm. In Deir al-Balah, children burned books to keep warm.
== History == SJS is named for Albert Mason Stevens and Frank Chambliss Johnson, American pediatricians who jointly published a description of the disorder in the American Journal of Diseases of Children in 1922.
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.
Cold storage slows the chemical degradation reactions that occur in solution. Lyophilized powder is more stable than reconstituted liquid and tolerates longer storage periods. Repeated temperature cycling should still be avoided because it can drive aggregation and loss of material.