A practical reference on tetrapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-03-28 and is reviewed periodically as new material appears.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Computed for the free acid of Ala-Glu-Asp-Gly |
| Molecular mass | About 390.35 g/mol | Free peptide; salt forms shift the value |
| Appearance | White to off-white solid | Typical of short peptides after freeze-drying |
| Solubility class | Freely soluble in water | Aqueous buffers are also commonly used |
| Common synonyms | Epitalon, epithalone, AEDG | AEDG is the single-letter sequence |
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
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 most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
Later, some eukaryotes that already contained mitochondria also engulfed cyanobacteria-like organisms, leading to the formation of chloroplasts in algae and plants. This is known as primary endosymbiosis.
The real chromatographic analysis starts with the introduction of the sample onto the column. The development of capillary gas chromatography resulted in many practical problems with the injection technique. The technique of on-column injection, often used with packed columns, is usually not possible with capillary columns. In the injection system in the capillary gas chromatograph the amount injected should not overload the column and the width of the injected plug should be small compared to the spreading due to the chromatographic process. Failure to comply with this latter requirement will reduce the separation capability of the column. As a general rule, the volume injected, Vinj, and the volume of the detector cell, Vdet, should be about 1/10 of the volume occupied by the portion of sample containing the molecules of interest (analytes) when they exit the column. Some general requirements which a good injection technique should fulfill are that it should be possible to obtain the column's optimum separation efficiency, it should allow accurate and reproducible injections of small amounts of representative samples, it should induce no change in sample composition, it should not exhibit discrimination based on differences in boiling point, polarity, concentration or thermal/catalytic stability, and it should be applicable for trace analysis as well as for undiluted samples. However, there are a number of problems inherent in the use of syringes for injection. Even the best syringes claim an accuracy of only 3%, and in unskilled hands, errors are much larger.
Christianity and Islam had the highest number of adherents among the religious citizens. Eastern Christianity predominated among Christians, with Russia's traditional Russian Orthodox Church being the largest Christian denomination. About 90% of the Soviet Union's Muslims were Sunnis, with Shias being concentrated in the Azerbaijan SSR. Smaller groups included Roman Catholics, Jews, Buddhists, and a variety of Protestant denominations (especially Baptists and Lutherans). Religious influence had been strong in the Russian Empire. The Russian Orthodox Church enjoyed a privileged status as the church of the monarchy and took part in carrying out official state functions. The immediate period following the establishment of the Soviet state included a struggle against the Orthodox Church, which the revolutionaries considered an ally of the former ruling classes. In Soviet law, the 'freedom to hold religious services' was constitutionally guaranteed, although the ruling Communist Party regarded religion as incompatible with the Marxist spirit of scientific materialism. In practice, the Soviet system subscribed to a narrow interpretation of this right, and in fact used a range of official measures to discourage religion and curb the activities of religious groups. The 1918 Council of People's Commissars decree establishing the Russian SFSR as a secular state also decreed that 'the teaching of religion in all [places] where subjects of general instruction are taught, is forbidden.
Iodine will kill all principal pathogens and, given enough time, even spores, which are considered to be the most difficult form of microorganisms to be inactivated by disinfectants and antiseptics. Octenidine dihydrochloride, currently increasingly used in continental Europe, often as a chlorhexidine substitute. Peroxides, such as hydrogen peroxide and benzoyl peroxide. Commonly, 3% solutions of hydrogen peroxide have been used in household first aid for scrapes, etc. However, the strong oxidization causes scar formation and increases healing time during fetal development. Phenols such as phenol itself (as introduced by Lister) and triclosan, hexachlorophene, chlorocresol, and chloroxylenol. The fact that the more substituted and more lipophylic phenols are less toxic, less irritant and more powerful was gradually discovered in late 19th century. Nowadays comparatively more water-soluble phenols such as chlorocresol are commonly used as preservatives in personal care products while less soluble such as chloroxylenol – as topical antiseptics. Both can be encountered in household disinfectants. Quat salts such as benzalkonium chloride/lidocaine (trade name Bactine among others), cetylpyridinium chloride, or cetrimide. These surfactants disrupt cell walls. Quinolines such as hydroxyquinolone, dequalium chloride, or chlorquinaldol. 4-Hexylresorcinol, or S.T.37
Sources: en.wikipedia.org
After more than a century of foreign rule, Poland regained its independence at the end of World War I as one of the outcomes of the negotiations that took place at the Paris Peace Conference of 1919. The Treaty of Versailles that emerged from the conference set up an independent Polish nation with an outlet to the sea, but left some of its boundaries to be decided by plebiscites. The largely German-inhabited Free City of Danzig was granted a separate status that guaranteed its use as a port by Poland. In the end, the settlement of the German-Polish border turned out to be a prolonged and convoluted process. The dispute helped engender the Greater Poland Uprising of 1918–1919, the three Silesian uprisings of 1919–1921, the East Prussian plebiscite of 1920, the Upper Silesia plebiscite of 1921 and the 1922 Silesian Convention in Geneva. Other boundaries were settled by war and subsequent treaties. A total of six border wars were fought in 1918–1921, including the Polish–Czechoslovak border conflicts over Cieszyn Silesia in January 1919.
The persistence of American unipolar predominance in the international system since the end of the Cold War has caused a rupture in the American school of Realist … theory ... Yet the ongoing failure of potential rivals to the US, such as China, Russia, or the EU to develop military capabilities that come anywhere close to those of the US seems to have defied this prediction. Despite the apparently radical imbalance of the international political system, smaller states are not trying to build up their military power to match that of the US or forming formal alliance systems to oppose it… The absence of balancing against the US constitutes a serious anomaly for neorealist theory. Fareed Zakaria asks, "Why is no one ganging up against the United States?" And John Ikenberry and John M. Owen ask the same question. Prominent Historian of the Cold War, John Lewis Gaddis, poses a more general question and replies: Do the weak always unite against the strong? "In theory, yes, but in practice and in history, not necessarily." One of the issues the discipline of political science "has been wrestling with recently is why there is still no anti-American coalition despite the overwhelming dominance of the United States since the end of the Cold War." French or Chinese officials publicly denounce "hyperpower" and aspire for "multipolarity" but refrain from forming a counterbalancing coalition. "Rhetorically, leaders and public want the United States to be balanced" but "we find very little balancing." French academic Michel Winock said: "Before we could say we were on American side.
=== Storage === Because mRNA is fragile, some vaccines must be kept at very low temperatures to avoid degrading and thus giving little effective immunity to the recipient. Pfizer–BioNTech's BNT162b2 mRNA vaccine has to be kept between −80 and −60 °C (−112 and −76 °F). Moderna says their mRNA-1273 vaccine can be stored between −25 and −15 °C (−13 and 5 °F), which is comparable to a home freezer, and that it remains stable between 2 and 8 °C (36 and 46 °F) for up to 30 days. In November 2020, it was reported, "While it's possible that differences in LNP formulations or mRNA secondary structures could account for the thermostability differences [between Moderna and BioNtech], many experts suspect both vaccine products will ultimately prove to have similar storage requirements and shelf lives under various temperature conditions." Several platforms are being studied that may allow storage at higher temperatures.
Salmon calcitonin (sCT) is the type of calcitonin hormone found in salmon. Similar to humans, salmon calcitonin is a peptide hormone produced in the ultimobranchial region by parafollicular cells in response to hypercalcemia and lowers blood calcium and phosphate by promoting renal excretion.
The free cysteine nucleophile forms a bond with the phosphorus atom of the phosphate moiety, and the P-O bond linking the phosphate group to the tyrosine is protonated, either by a suitably positioned acidic amino acid residue (Asp in the diagram below) or a water molecule. The phospho-cysteine intermediate is then hydrolysed by another water molecule, thus regenerating the active site for another dephosphorylation reaction. Metallo-phosphatases (e.g. PP2C) co-ordinate 2 catalytically essential metal ions within their active site. There is currently some confusion of the identity of these metal ions, as successive attempts to identify them yield different answers. There is currently evidence that these metals could be magnesium, manganese, iron, zinc, or any combination thereof. It is thought that a hydroxyl ion bridging the two metal ions takes part in nucleophilic attack on the phosphorus ion.
Sources: en.wikipedia.org
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.
Epitalon and epithalon both circulate, and the difference reflects transliteration of a name coined in Russian-language publications. Reference to the extract it derives from, epithalamin, explains the shared stem. Databases and suppliers are inconsistent, so a search for one spelling alone may miss relevant entries.
No. Epithalamin is a multi-component preparation obtained from pineal tissue, and its exact composition is not fully characterised. Epitalon is a single defined tetrapeptide described as a short synthetic counterpart of that extract, so the two are related in origin but not interchangeable in identity.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.