tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-10-08. Anything still debated is marked as such rather than presented as settled.
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.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
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.
| 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 |
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.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
The original source of most nutrients, including micronutrients, is the geological reservoir, also called the slow pool. Micronutrients trapped in rocks and minerals must first be broken down through physical or chemical weathering before they can enter the fast pool, meaning they cycle between reservoirs on shorter timescales. Micronutrients can physically exchange between reservoirs in various ways such as from terrestrial soils to oceans via aeolian transport or fluvial transport, from oceans to marine sediments via deposition of organic matter, and from sediments to the geologic reservoir via lithification. Alternatively, micronutrients can exit the geologic reservoir through tectonic processes such as through volcanism or hydrothermal vents.
Each person carries 2 alleles of each of the 3 class-I genes, (HLA-A, HLA-B and HLA-C), and so can express six different types of MHC-I (see figure). In the class-II locus, each person inherits a pair of HLA-DP genes (DPA1 and DPB1, which encode α and β chains), a couple of genes HLA-DQ (DQA1 and DQB1, for α and β chains), one gene HLA-DRα (DRA1), and one or more genes HLA-DRβ (DRB1 and DRB3, -4 or -5). That means that one heterozygous individual can inherit six or eight functioning class-II alleles, three or more from each parent. The role of DQA2 or DQB2 is not verified. The DRB2, DRB6, DRB7, DRB8 and DRB9 are pseudogenes. The set of alleles that is present in each chromosome is called the MHC haplotype. In humans, each HLA allele is named with a number. For instance, for a given individual, his haplotype might be HLA-A2, HLA-B5, HLA-DR3, etc... Each heterozygous individual will have two MHC haplotypes, one each from the paternal and maternal chromosomes. The MHC genes are highly polymorphic; many different alleles exist in the different individuals inside a population. The polymorphism is so high, in a mixed population (nonendogamic), no two individuals have exactly the same set of MHC molecules, with the exception of identical twins. The polymorphic regions in each allele are located in the region for peptide contact. Of all the peptides that could be displayed by MHC, only a subset will bind strongly enough to any given HLA allele, so by carrying two alleles for each gene, each encoding specificity for unique antigens, a much larger set of peptides can be presented.
The breasts reach full maturity only when a woman's first pregnancy occurs. Changes to the breasts are among the first signs of pregnancy. The breasts become larger, the nipple-areola complex becomes larger and darker, the Montgomery's glands enlarge, and veins sometimes become more visible. Breast tenderness during pregnancy is common, especially during the first trimester. By mid-pregnancy, the breast is physiologically capable of lactation and some women can express colostrum, a form of breast milk. Pregnancy causes elevated levels of the hormone prolactin, which has a key role in the production of milk. However, milk production is blocked by the hormones progesterone and estrogen until after delivery, when progesterone and estrogen levels plummet.
Chocolate manufacturers produce a range of products from chocolate bars to fudge. Large manufacturers of chocolate products include Cadbury, Ferrero, Guylian, The Hershey Company, Lindt & Sprüngli, Mars, Incorporated, Milka, Neuhaus and Suchard. Guylian is best known for its chocolate sea shells; Cadbury for its Dairy Milk and Creme Egg. The Hershey Company, the largest chocolate manufacturer in North America, produces the Hershey Bar and Hershey's Kisses. Mars Incorporated, a large privately owned U.S. corporation, produces Mars Bar, Milky Way, M&M's, Twix, and Snickers. Lindt is known for its truffle balls and gold foil-wrapped Easter bunnies. Food conglomerates Nestlé SA and Mondelēz both have chocolate brands. Nestlé acquired Rowntree's in 1988 and now markets chocolates under their brand, including Smarties (a chocolate candy) and Kit Kat (a chocolate bar); Kraft Foods through its 1990 acquisition of Jacobs Suchard, now owns Milka and Suchard. Fry's, Trebor Basset and the fair trade brand Green & Black's also belongs to the group.
Sources: en.wikipedia.org
=== General information === Colombia at Britannica.com Lamoureux, Andrew Jackson; Edmundson, George (1911). "Colombia" . Encyclopædia Britannica. Vol. 6 (11th ed.). pp. 700–713. Official investment portal Official Colombia Tourism Website (in Spanish) National Administrative Department of Statistics
AbbVie Inc., also known as AbbVie, is an American pharmaceutical company headquartered in North Chicago, Illinois. AbbVie produces drugs to treat a wide range of medical issues. The company is ranked sixth on the list of largest biomedical companies by revenue. It is ranked 77th on the Fortune 500 and 108th on the Forbes Global 2000. The name "AbbVie" is derived from a combination of "Abbott", the name of its former parent company, with "vie", intended as a reference to a Latin root meaning 'life'.
=== Redox buffer in the irradiated fuel matrix === Molybdenum behaves as a redox buffer in the spent nuclear fuel matrix. 99Mo is one of the most abundant fission product, with a fission yield of 6.1% close to that of xenon (135Xe, 6.33%). Molybdenum plays a critical role in nuclear fuel chemistry because it affects the fuel's oxygen fugacity. Molybdenum produced by nuclear fission in the fuel matrix inhibits the oxidation of the uranium dioxide.
This is a list of episodes for the series Legend of the Galactic Heroes. In-universe dates are given in the Universal Calendar (U.C.) used in the Free Planets Alliance and the Imperial Calendar (R.C.) used in the Galactic Empire.
== History and development == The first site was launched in 2001 by the American Association for Clinical Chemistry, the scientific society for clinical laboratory science. This led to a collaboration with professional societies in 17 other countries representing the laboratory medicine community. Each site is separately managed to allow both appropriate languages and information that matches local needs.
Sources: en.wikipedia.org
Whereas increasing the dose of opioid can be an effective way to overcome tolerance, doing so to compensate for opioid-induced hyperalgesia may worsen the patient's condition by increasing sensitivity to pain while escalating physical dependence. This "uncommon but important phenomenon [can be] seen with high-dose opioid therapy." However, the conclusion of a report published in the Journal of Pain and Palliative Care Pharmacotherapy suggests that "[h]yperalgesia shares a common mechanism with tolerance and it may be that hyperalgesia is a manifestation of tolerance itself."
==== Self-assembled recombinant spider silk nanomembranes ==== Gustafsson et al. demonstrated free‐standing, bioactive membranes of cm-sized area, but only 250 nm thin, that were formed by self‐assembly of spider silk at the interface of an aqueous solution. The membranes uniquely combine nanoscale thickness, biodegradability, ultrahigh strain and strength, permeability to proteins and promote rapid cell adherence and proliferation. They demonstrated growing a coherent layer of keratinocytes. These spider silk nanomembranes have also been used to create a static in-vitro model of a blood vessel.
== Dehydration methods == People have practiced food preservation since ancient times. Many folktales describe ways of preserving foods in one way or another according to local and cultural traditions. Dehydration methods help to prevent food from spoilage and to maintain it for a longer period of time while keeping it suitable for consumption. Reducing the amount of water in fruits helps prevent growth of bacteria, yeast or fungi. There are several processes that can be used in the production of dried fruit, each of which affects its appearance, rehydration properties, and nutrients differently. These drying processes include sun drying, tray (air) drying, freeze drying, and vacuum microwave drying. Each process has advantages and disadvantages.
=== Marine adhesion === l-DOPA is a key compound in the formation of marine adhesive proteins, such as those found in mussels. It is believed to be responsible for the water-resistance and rapid curing abilities of these proteins. l-DOPA may also be used to prevent surfaces from fouling by bonding antifouling polymers to a susceptible substrate. The versatile chemistry of l-DOPA can be exploited in nanotechnology. For example, DOPA-containing self-assembling peptides were found to form functional nanostructures, adhesives and gels.
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.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.