A practical reference on Tetrapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-26. Anything still debated is marked as such rather than presented as settled.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
== Medical uses == For over 90 years, hematopoietic stem cell transplantation (HSCT) has been used to treat people with conditions such as leukemia and lymphoma; this is the only widely practiced form of stem-cell therapy. During chemotherapy, most growing cells are killed by the cytotoxic agents. These agents, however, cannot discriminate between the leukaemia or neoplastic cells, and the hematopoietic stem cells within the bone marrow. This is the side effect of conventional chemotherapy strategies that the stem-cell transplant attempts to reverse; a donor's healthy bone marrow reintroduces functional stem cells to replace the cells lost in the host's body during treatment. The transplanted cells also generate an immune response that helps to kill off the cancer cells; this process can go too far, however, leading to graft vs host disease, the most serious side effect of this treatment. Another stem-cell therapy called Prococvhymal, was conditionally approved in Canada in 2012 for the management of acute graft-vs-host disease in children who are unresponsive to steroids. It is an allogenic stem therapy based on mesenchymal stem cells (MSCs) derived from the bone marrow of adult donors. MSCs are purified from the marrow, cultured and packaged, with up to 10,000 doses derived from a single donor. The doses are stored frozen until needed. The FDA has approved five hematopoietic stem-cell products derived from umbilical cord blood, for the treatment of blood and immunological diseases.
=== Inhibition === NADPH oxidase can be inhibited by apocynin, nitric oxide (NO), and diphenylene iodonium. Apocynin acts by preventing the assembly of the NADPH oxidase subunits. Apocynin decreases influenza-induced lung inflammation in mice in vivo and so may have clinical benefits in the treatment of influenza. Inhibition of NADPH oxidase by NO blocks the source of oxidative stress in the vasculature. NO donor drugs (nitrovasodilators) have therefore been used for more than a century to treat coronary artery disease, hypertension, and heart failure by preventing excess superoxide from deteriorating healthy vascular cells. More advanced NADPH oxidase inhibitors include GKT-831 (Formerly GKT137831), a dual Inhibitor of isoforms NOX4 and NOX1 which was patented in 2007. The compound was initially developed for Idiopathic pulmonary fibrosis and obtained orphan drug designation by the FDA and EMA at end of 2010.
== Proposal of protein primary structure == Hofmeister argued for peptide bonds by process of elimination. C-C, ether and ester bonds were unlikely considering the digestion by trypsin. R=C-N-C=R bonds could be eliminated because it would imply a much larger number of carboxylate groups than is observed experimentally. Hofmeister also argued for peptide bonds based on the biuret reaction observed with all proteins but never with free amino acids. Since biuret has the formula NH2-CO-NH-CO-NH2, that suggested the presence of similar peptide bonds in proteins.
=== Sports === Current evidence-based studies show that unusually high levels of circulating testosterone are associated with increased athletic performance in women, unless they lack androgen sensitivity. However, controversy has emerged in the form of the claim that testosterone is not unlike any other physical parameter with reference to bestowing advantages or disadvantages on female athletes. Existing regulations throughout competitive sports are currently being refined to specifically address this particular claim. Following the case of South African athlete Caster Semenya, an athlete with a difference in sex development (DSD) and internal testes, the International Association of Athletics Federations introduced its hyperandrogenism regulations, which restricted those registered as women with high testosterone levels, whether the hormones were produced by ovaries, adrenals, or testes. These regulations replaced the earlier sex verification rules. Following a series of legal challenges, regulations called the Eligibility Regulations for the Female Classification (Athletes with Differences of Sexual Development) were released on 1 May 2019. These regulations apply only to athletes who have a DSD, high testosterone and virilization, and no longer include hyperandrogenism from non-DSD-related causes such as PMOS. Such DSDs, often seen in people who have a Y chromosome and testes, include 5α‐reductase deficiency, partial androgen insensitivity, and congenital adrenal hyperplasia.
=== Ministerial level === On March 18, Awais Leghari was relieved from his portfolio as Minister for Railways in favour for taking over the Ministry of Energy, formerly under Musadik Malik. On 29 March, Amir Muqam was relieved of his additional portfolio as Federal Minister of National Heritage and Culture, instead taking over the Kashmir Affairs and Gilgit-Baltistan portfolio. On April 4 five portfolios were assigned to different federal ministers previously held by the prime minister, Aleem Khan was given the additional portfolio of communications, Chaudhry Salik Hussain was allocated Religious Affairs and Interfaith Harmony, Rana Tanveer Hussain allocated Food Security & Research, Ahsan Iqbal was allocated inter-provincial coordination and Musadik Malik was allocated water resources.
Sources: en.wikipedia.org
=== Behavior === Glo1 expression is correlated with differences in anxiety-like behavior in mice as well as behavior in the tail suspension test, which is sensitive to antidepressant drugs; however, the direction of these effects have not always been consistent, which has raised skepticism. Differences in Glo1 expression in mice appear to be caused by a copy number variant that is common among inbred strains of mice. It has been proposed that the behavioral effects of Glo1 are due to the activity of its principal substrate methylglyoxal at GABAA receptors. A small molecule inhibitor of glyoxalase I has been shown to have anxiolytic properties, thus identifying another possible indication for inhibitors of Glyoxalase I.
== Adverse effects == Chemotherapeutic techniques have a range of side effects that depend on the type of medications used. The most common medications affect mainly the fast-dividing cells of the body, such as blood cells and the cells lining the mouth, stomach, and intestines. Chemotherapy-related iatrogenic toxicities can occur acutely after administration, within hours or days, or chronically, from weeks to years.
== Reference terminology == The terminology of isotopic reference materials is not applied consistently across subfields of isotope geochemistry or even between individual laboratories. The terminology defined below comes from Gröening et al. (1999) and Gröening (2004). Reference materials are the basis for accuracy across many different types of measurement, not only the mass spectrometry, and there is a large body of literature concerned with the certification and testing of reference materials.
Independent research: this would be work done with core or flexible funding that allows the researchers the liberty to choose their research questions and method. It may be long term and could emphasize 'big ideas' without direct policy relevance. However, it could emphasize a major policy problem that requires a thorough research and action investment. Consultancy: this would be work done by commission with specific clients and addressing one or two major questions. Consultancies often respond to an existing agenda. Influencing/advocacy: this would be work done by communications, capacity development, networking, campaigns, lobbying, etc. It is likely to be based on research based evidence emerging from independent research or consultancies. Second, policy institutes may base their work or arguments on:
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.