If you have been reading about AEDG tetrapeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-08. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
| 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 |
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.
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.
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.
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 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.
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.
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.
== Nuclear energy applications == In a fission nuclear reactor, uranium-238 can be used to generate plutonium-239, which itself can be used in a nuclear weapon or as a nuclear-reactor fuel supply. In a typical nuclear reactor, up to one-third of the generated power comes from the fission of 239Pu, which is not supplied as a fuel to the reactor, but rather, produced from 238U. A certain amount of production of 239Pu from 238U is unavoidable wherever it is exposed to neutron radiation. Depending on burnup and neutron temperature, different shares of the 239Pu are converted to 240Pu, which determines the "grade" of produced plutonium, ranging from weapons grade, through reactor grade, to plutonium so high in 240Pu that it cannot be used in current reactors operating with a thermal neutron spectrum. The latter usually involves used "recycled" MOX fuel which entered the reactor containing significant amounts of plutonium.
===== Sulfonylureas ===== Sulfonylureas act by increasing insulin release from the beta cells in the pancreas. A 2019 systematic review suggested that there is limited evidence if the combined use of metformin with sulfonylurea compared to the combination of metformin plus another glucose-lowering intervention, provides benefit or harm in mortality, severe adverse events, macrovascular and microvascular complications. Combined metformin and sulfonylurea therapy did appear to lead to a higher risk of hypoglycemia. Metformin is available combined with the sulfonylureas glipizide (Metaglip) and glibenclamide (US: glyburide) (Glucovance). Generic formulations of metformin/glipizide and metformin/glibenclamide are available (the latter is more popular).
=== Toxicity === Today nicotine is less commonly used in agricultural insecticides, which was a main source of poisoning. More recent cases of poisoning typically appear to be in the form of Green Tobacco Sickness (GTS), accidental ingestion of tobacco or tobacco products, or ingestion of nicotine-containing plants. People who harvest or cultivate tobacco may experience GTS, a type of nicotine poisoning caused by dermal exposure to wet tobacco leaves. This occurs most commonly in young, inexperienced tobacco harvesters who do not consume tobacco. People can be exposed to nicotine in the workplace by breathing it in, skin absorption, swallowing it, or eye contact. The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for nicotine exposure in the workplace as 0.5 mg/m3 skin exposure over an 8-hour workday. The US National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.5 mg/m3 skin exposure over an 8-hour workday. At environmental levels of 5 mg/m3, nicotine is immediately dangerous to life and health.
Although vultures are the only birds that depend on carrion for food, many other birds eat carrion opportunistically. Numerous birds of prey, for example wedge-tailed eagles, brown goshawks and buzzards, feed on carrion. Long-eared owls and great horned owls also feed on carrion, as do wading birds such as the marabou stork and greater adjutant, seabirds such as the northern giant petrel and ivory gull, and passerine birds such as the carrion crow, rook and forest raven. Types of carrion eaten include dead wildlife, dead livestock, roadkill, and carrion stolen from vultures or raided from crocodile caches.
Sources: en.wikipedia.org
=== Comparison with other expression systems === In standard molecular biology research, the bacterium Escherichia coli is the most frequently used organism for expression system, to produce heterologous proteins, due to its features of fast growth rate, high protein production rate, as well as undemanding growth conditions. Protein production in E. coli is usually faster than that in Komagataella, with reasons: Competent E. coli cells can be stored frozen, and thawed before use, whereas Komagataella cells have to be produced immediately before use. Expression yields in Komagataella vary between different clones, so that a large number of clones has to be screened for protein production, to find the best producer. The biggest advantage of Komagataella over E. coli is that Komagataella is capable of forming disulfide bonds and glycosylations in proteins, but E. coli cannot. E. coli might produce a misfolded protein when disulfides are included in final product, leading to inactive or insoluble forms of proteins. The well-studied Saccharomyces cerevisiae is also used as an expression system with similar advantages over E. coli as Komagataella. However Komagataella has two main advantages over S. cerevisiae in laboratory and industrial settings:
The general strategy adopted by most present-day competitive bodybuilders is to make muscle gains for most of the year (known as the "off-season") and, approximately 12–14 weeks from competition, lose a maximum of body fat (referred to as "cutting") while preserving as much muscular mass as possible. The bulking phase entails remaining in a net positive energy balance (calorie surplus). The amount of a surplus in which a person remains is based on the person's goals, as a bigger surplus and longer bulking phase will create more fat tissue. The surplus of calories relative to one's energy balance will ensure that muscles remain in a state of anabolism. The cutting phase entails remaining in a net negative energy balance (calorie deficit). The main goal of cutting is to oxidize fat while preserving as much muscle as possible. The larger the calorie deficit, the faster one will lose weight. However, a large calorie deficit will also create the risk of losing muscle tissue. The bulking and cutting strategy is considered effective because there is a well-established link between muscle hypertrophy and being in a state of positive energy balance. A sustained period of caloric surplus will allow the athlete to gain more fat-free mass than they could otherwise gain under eucaloric conditions. Some gain in fat mass is expected, which athletes seek to oxidize in a cutting period while maintaining as much lean mass as possible. However, it is unclear whether one can maintain enough fat-free mass during cutting for the overall process to be worth it.
=== Reunion === The Doobies did not work together for the next five years, though various members got together in different configurations for annual Christmas season performances for the patients and staff at the Stanford Children's Hospital in the Bay area. Simmons released a commercially disappointing solo album, Arcade, in April 1983. During the mid-1980s, Johnston toured U.S. clubs with a band called Border Patrol, which did not release any recordings. Hossack and (briefly) Simmons worked with the group. Around 1986, Johnston and Simmons began working on an album together (according to a 1989 interview with Simmons) but abandoned the project soon after with no known finished tracks. In 1983, Knudsen and McFee formed the band Southern Pacific and recorded four albums that found success in the country charts (former Creedence Clearwater Revival bassist Stu Cook joined the band in 1986 and former Pablo Cruise guitarist David Jenkins in 1988). Out of print for many years, Simmons' Arcade was reissued on compact disc in 2007 by specialty label Wounded Bird Records, which is also the home of Southern Pacific's and Tom Johnston's catalogs. Post-Doobies, McDonald became established as a solo artist. His voice dominated adult contemporary radio throughout the 1980s, and he experienced a renaissance of popularity in the 21st century as an interpreter of Motown classics. The reformation of the Doobie Brothers was not intentional. On a personal quest for a worthy cause and after conquering his drug addiction, Knudsen became active in the Vietnam Veterans Aid Foundation.
=== Pregnancy === Paracetamol has long been established as a safe medication to treat short-term fever and significant pain in pregnant patients. Regulatory agencies, including the European Medicines Agency (EMA), the Medicines and Healthcare products Regulatory Agency (MHRA), the World Health Organization (WHO), and the U.S. Food and Drug Administration (FDA) recommend paracetamol as a first-line analgesic and antipyretic in pregnancy, with use limited to situations where necessary, at the lowest effective dose, and for the shortest duration. Some observational studies have suggested a possible association between prenatal paracetamol use and neurodevelopmental disorders, including ADHD and autism. However, these studies are limited by confounding factors such as maternal fever and infection, and do not demonstrate causation. Large, well-controlled studies, including sibling-controlled analyses, find no causal link after adjusting for maternal conditions. In support of existing recommendations for its safe use during pregnancy, a 2026 review found that there were no clinically significant increases in the occurrence of autism, attention deficit hyperactivity disorder, or intellectual disability in the children of pregnant women who used paracetamol as directed. Untreated pain and fever can harm mother and fetus.
F-box protein (FBP) – FBP contributes to the substrate specificity of the SCF complex by first aggregating to target proteins independently of the complex. Each FBP (e.g. Skp2) may recognize several different substrates in a manner that is dependent on post-translational modifications such as phosphorylation or glycosylation. FBP then binds to Skp1 of the SCF complex using an F-box motif, bringing the target protein into proximity with the functional E2 ubiquitin-conjugating enzyme. FBP is also essential in regulating SCF activity during the course of the cell cycle. SCF levels are thought to remain constant throughout the cell-cycle. Instead, FBP affinity for protein substrates is regulated through cyclin-CDK-mediated phosphorylation of target proteins. Skp1 – Skp1 is an adaptor protein that is essential for the recognition and binding of F-box proteins. Cullin (CUL1) – Cullin forms the major structural scaffold of the SCF complex and links the skp1 domain to the Rbx1 domain. Different combinations of Cullin and FBPs can generate on the order of a hundred types of E3 ubiquitin ligases that target different substrates. RBX1 – Rbx1 contains a small, zinc-binding Really Interesting New Gene (RING) finger domain, to which the E2 ubiquitin-conjugating enzyme binds. This binding event allows the transferral of ubiquitin from E2 to a lysine residue on the target protein.
Sources: en.wikipedia.org
A few of the latter are so rare that they were not discovered in nature, but were synthesized in the laboratory before it was determined that they exist in nature: technetium (element 43), promethium (element 61), astatine (element 85), neptunium (element 93), and plutonium (element 94). No element heavier than einsteinium (element 99) has ever been observed in macroscopic quantities in its pure form, nor has astatine; francium (element 87) has been only photographed in the form of light emitted from microscopic quantities. Of the 94 natural elements, eighty have a stable isotope and one more (bismuth) has an almost-stable isotope (with a half-life of 2.01×1019 years, over a billion times the age of the universe). Two more, thorium and uranium, have isotopes undergoing radioactive decay with a half-life comparable to the age of the Earth. The stable elements plus bismuth, thorium, and uranium make up the 83 primordial elements that survived from the Earth's formation. The remaining eleven natural elements decay quickly enough that their continued trace occurrence rests primarily on being constantly regenerated as intermediate products of the decay of thorium and uranium. All 24 known artificial elements are radioactive.
== Prevalence and popularity == Globally, 14.3% of married or partnered women of reproductive age (15–49) use intrauterine contraception as their preferred method of family planning. A study found that female family planning providers choose LARC methods more often (41.7%) than the general public (12.1%). However, the adoption of IUDs varies significantly across different regions. In Asia, IUD is particularly popular, with 27% of contraceptive users relying on it, while in Oceania, the usage rate is much lower at 1.8%. Geographically, the majority of IUD users—over 80% worldwide—are concentrated in Asia, with nearly two-thirds (64%) of these users living in China, according to a 2011 United Nations review. IUD use is more prevalent in less developed regions (15.1% of women) compared to more developed regions (9.2% of women). Within continents, there are significant variations. For instance, in Europe, IUD use ranges from 5% in Southern Europe to 16–28% in countries like France and Scandinavia. In Africa, IUD use is relatively low in sub-Saharan regions (less than 2%) but higher in Northern Africa, particularly in countries such as Egypt (36.1%) and Tunisia (27.8%). In the United States, the use of IUDs increased from 0.8% in 1995 to 7.2% from the period of 2006 to 2014 and to 10.5% in a 2017-2019 survey. IUD usage rates are also influenced by ethnicity within the United States, with Hispanic women more likely to use IUD compared to Caucasian women. Among birth control methods, IUDs, along with other contraceptive implants, result in the greatest satisfaction among users.
Beginning in 1928, Stalin's five-year plans for the national economy of the Soviet Union achieved the rapid industrialisation (coal, iron and steel, electricity and petroleum, among others) and the collectivisation of agriculture. It achieved 23.6% of collectivisation within two years (1930) and 98.0% of collectivisation within thirteen years (1941). As the revolutionary vanguard, the communist party organised Russian society to realise rapid industrialisation programs as defence against Western interference with socialism in Bolshevik Russia. The five-year plans were prepared in the 1920s whilst the Bolshevik government fought the internal Russian Civil War (1917–1922) and repelled the external Allied intervention to the Russian Civil War (1918–1925). Vast industrialisation was initiated mostly based with a focus on heavy industry. The Cultural revolution in the Soviet Union focused on restructuring culture and society.
Aeroponics Anthroponics Aquaponics Digeponics Fogponics Folkewall Grow box Growroom Nutrient film technique Organoponics Passive hydroponics Plant factory Plant nutrition Plant pathology Root rot Vertical farming Xeriscaping
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 built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.