Tetrapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-12-03. Numbers and descriptions here follow the published literature rather than marketing material.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
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.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
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.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
=== Type 1 PSSM === Type 1 PSSM is caused by an autosomal dominant genetic mutation known as GSY1. This mutation causes an up-regulation of glycogen synthase, and high levels of glycogen synthase relative to glycogen branching enzyme (GBE). This altered ratio of glycogen synthase to GBE results in glycogen molecules with long chains and few branches, making these molecules somewhat resistant to amylase breakdown on amylase-PAS (periodic acid-Schiff) stained biopsies. The GSY1 mutation is associated with altered glucose metabolism (but normal glycogen metabolism), as well as accumulation of high levels of glycogen and abnormal polysaccharide in the muscles of the horse. Additionally, some horses have been shown to have insulin sensitivity, which improves glucose uptake by muscle cells and contributes to excessive glycogen storage that is already elevated secondary to the GSY1 mutation.
First, Article 102 of the Treaty on the Functioning of the European Union prohibits "abuse by one or more undertakings of a dominant position". A "dominant position" is presumed to exist with over a 50% market share, and may exist with a 39.7% market share. There may also be dominance through control of data, or by a group of undertakings acting collectively, and a corporate group will be treated as a "single economic unit" for the purpose of calculating market share. The prohibited categories of "abuse" are unlimited, but article 102 explicitly spells out the bans on (a) "unfair purchase or selling prices", (b) "limiting production", (c) "applying dissimilar conditions to equivalent transactions", and (d) imposing unconnected "supplementary obligations" to contracts. In a leading case on (a) unfair prices, United Brands Co v Commission held that, although a banana company had a dominant position in its product and geographic markets (because bananas were not easily substituted with other fruit, and its relevant market share was 40 to 45%), prices 7% higher than rivals were not enough to be an abuse. By contrast prices 25% higher than a company's estimated costs were found to be unfair. Unfair pricing also includes predatory pricing, where a company cuts its own selling prices to bankrupt a competitor: there is a presumption of abuse if a company prices "below average variable costs", namely "those which vary depending on the quantities produced". There is no requirement to show losses might be recouped.
In January 2023, US president Joe Biden invited Lula to meet him in Washington, D.C., in February 2023 following a phone conversation between them on the 2023 Brazilian Congress attack. White House press secretary Karine Jean-Pierre confirmed the meeting adding that it would address "U.S. support of Brazil's democracy and how the two countries can continue to work together to promote inclusion and democratic values in the region and around the world". Climate change, migration, economic development and security matters were also discussed. In February 2023, Lula and a delegation including his Foreign Affairs special advisor Celso Amorim, Foreign minister Mauro Vieira, Finance minister Fernando Haddad, Racial Equality minister Anielle Franco, Environment e Climate Justice minister Marina Silva travelled to the US. During the trip Lula met with US Senator Bernie Sanders, Democratic House Representatives Alexandria Ocasio-Cortez, Pramila Jayapal, Sheila Jackson Lee, Brad Sherman and Ro Khanna before he met with US president Joe Biden at the White House. On 10 February, at a meeting with American president Joe Biden, Lula proposed the creation of a group of negotiators made up of countries "not involved in the war" (either directly or indirectly, i.e.
Sources: en.wikipedia.org
Thus, a high ratio of [NADH] to [NAD+] or a high ratio of [ADP] [Pi] to [ATP] imply a high amount of reduced cytochrome c and a high level of cytochrome c oxidase activity. An additional level of regulation is introduced by the transport rates of ATP and NADH between the mitochondrial matrix and the cytoplasm.
=== Mechanical equivalent of heat === A key stage in the development of the modern conservation principle was the demonstration of the mechanical equivalent of heat. The caloric theory maintained that heat could neither be created nor destroyed, whereas conservation of energy entails the contrary principle that heat and mechanical work are interchangeable. In the middle of the eighteenth century, Mikhail Lomonosov, a Russian scientist, postulated his corpusculo-kinetic theory of heat, which rejected the idea of a caloric. Through the results of empirical studies, Lomonosov came to the conclusion that heat was not transferred through the particles of the caloric fluid. In 1798, Count Rumford (Benjamin Thompson) performed measurements of the frictional heat generated in boring cannons and developed the idea that heat is a form of kinetic energy; his measurements refuted caloric theory, but were imprecise enough to leave room for doubt.
In Lao cuisine, Lao coriander is used extensively in traditional Lao dishes such as 'mok pa' (steamed fish in banana leaf) and several coconut milk curries that contain fish or prawns. In China dill is called colloquially, 'huíxiāng' (茴香, perfume of Hui people), or more properly 'shíluó' (莳萝/蒔蘿). It is a common filling in 'baozi', 'jiaozi' and 'xianbing' and may be used as vegetarian with rice vermicelli, or combined with either meat or eggs. Vegetarian dill baozi are a common part of a Beijing breakfast. In baozi and xianbing, it often is interchangeable with non-bulbing fennel and the term 茴香 also may refer to fennel, similarly to caraway and coriander leaf, sharing a name in Chinese as well. Dill also may be stir fried as a potherb, often with egg, in the same manner as Chinese chives. In Northern China, Beijing, Inner-Mongolia, Ningxia, Gansu, and Xinjiang, dill seeds commonly are called 'zīrán' (孜然), but also 'kūmíng' (枯茗), 'kūmíngzi' (枯茗子), 'shíluózi' (莳萝子/蒔蘿子), 'xiǎohuíxiāngzi' (小茴香子) and are used with pepper for lamb meat. In the whole of China, 'yángchuàn' (羊串) or 'yángròu chuàn' (羊肉串), lamb brochette, a speciality from Uyghurs, uses cumin and pepper. In Cantonese-speaking regions such as Hong Kong and Macau, the leaves are more colloquially known as 刁草 (diu1 cou2), a partial calque of the English 'dillweed'; 'dill' transliterated into the otherwise unrelated 刁 diu1 and 'weed' translated as 草 cou2. In Taiwan, it is also commonly used as a filling in steamed buns (baozi) and dumplings (jiaozi). In Vietnam, the use of dill in cooking is regional.
Sources: en.wikipedia.org
== Pathophysiology == HHS is usually precipitated by an infection, myocardial infarction, stroke or another acute illness. A relative insulin deficiency leads to a serum glucose that is usually higher than 33 mmol/L (600 mg/dL), and a resulting serum osmolarity that is greater than 320 mOsm. This leads to excessive urination (more specifically an osmotic diuresis), which, in turn, leads to volume depletion and hemoconcentration that causes a further increase in blood glucose level. Ketosis is absent because the presence of some insulin inhibits hormone-sensitive lipase-mediated fat tissue breakdown.
the Division Artillery consisted of: Battery A, 319th Artillery Battery B, 319th Artillery Battery C, 319th Artillery (Battery C, 320th Artillery after 1960; C-319th accompanied the 2d ABG, 503d Infantry on its assignment to the 25th Infantry Division) Battery D, 320th Artillery Battery E, 320th Artillery Battery B, 377th Artillery additional division elements consisted of: 82nd Medical Company 82nd Signal Battalion 82nd Aviation Company Troop A, 17th Cavalry 307th Airborne Engineer Battalion 407th Supply and Transportation Battalion (The 82nd Quartermaster Parachute Supply and Maintenance Company [activated 1 March 1945] was reorganized and redesignated as Company B, 407th S&T Battalion.) 782nd Maintenance Battalion The pentomic organization was unsuccessful. In 1964, the division reorganized into three brigades of three battalions, the Reorganization Objective Army Division (ROAD) organization.
The categorization according to the specific function mainly include: exterior-releasing or exterior-resolving, heat-clearing, downward-draining, or precipitating wind-damp-dispelling, dampness-transforming, promoting the movement of water and percolating dampness or dampness-percolating, interior-warming, qi-regulating or qi-rectifying, dispersing food accumulation or food-dispersing, worm-expelling, stopping bleeding or blood-stanching, quickening the Blood and dispelling stasis or blood-quickening, transforming phlegm, stopping coughing and calming wheezing or phlegm-transforming and cough- and panting-suppressing, Spirit-quieting, calming the liver and expelling wind or liver-calming and wind-extinguishing orifice-opening supplementing which includes qi-supplementing, blood-nourishing, yin-enriching, and yang-fortifying, astriction-promoting or securing and astringing, vomiting-inducing, and substances for external application.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.