This is a working overview of epithalamin, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-28 and is reviewed periodically as new material appears.
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.
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.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
| 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 |
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.
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.
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.
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.
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.
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==== Thiolated chitosan ==== Thiolated chitosan is produced by attaching thiol groups to the amino groups of chitosan using a thiol-containing coupling agent. The primary site for this modification is the amino group at the 2nd position of chitosan's glucosamine units. During this process, thioglycolic acid and cysteine mediate the reaction, forming an amide bond between the thiol group and chitosan. At a pH below 5, thiol activity is reduced, which limits disulfide bond formation. The modified chitosan exhibits improved adhesive properties and stability due to the covalent attachment of the thiol groups. Lower pH reduces oxidation, enhancing its adhesion properties. Additionally, thiolated chitosan can interact with cell membrane receptors, improving membrane permeability and showing potential for applications in bacterial adhesion prevention, for example for coating stainless steel.
=== More examples === acetaldehyde dehydrogenase alcohol dehydrogenase Delta12-fatty acid dehydrogenase glutamate dehydrogenase (an enzyme that can convert glutamate to α-Ketoglutarate and vice versa). lactate dehydrogenase (used to convert NADH back to NAD+ in anaerobic glycolysis, and in the back reaction to produce NADH) pyruvate dehydrogenase (A common enzyme that feeds the TCA Cycle by converting pyruvate to acetyl CoA, using NAD+. In this reaction, the substrate not only is oxidized but also loses a carbon dioxide molecule, and is attached to the CoA coenzyme.) glucose-6-phosphate dehydrogenase (involved in the pentose phosphate pathway, producing NADPH) glyceraldehyde-3-phosphate dehydrogenase (involved in glycolysis, uses NAD+) sorbitol dehydrogenase TCA cycle examples:
Sources: en.wikipedia.org
=== Commercial production === Industrial production of vitamin B12 is achieved through fermentation of selected microorganisms. As noted above, the completely synthetic laboratory synthesis of B12 was achieved by Robert Burns Woodward and Albert Eschenmoser in 1972, though this process has no commercial potential, requiring more than 70 steps and having a yield well below 0.01%.
Modafinil is commercially available in 100 mg and 200 mg oral tablet forms. Additionally, it is offered as the (R)-enantiomer, known as armodafinil, and as a prodrug named adrafinil. Armodafinil is available in 50, 150, 200, and 250 mg tablets. A 100 mg dose of modafinil has been said to be essentially equivalent to a 50 mg dose of armodafinil in terms of drug levels.
== Description == This clade circumscribes five subordinate clades: two traditional tribes (Hypocalypteae and Indigofereae) and three informal clades (the mirbelioids, the millettioids, and Hologalegina), as well as several minor taxa. The name of this clade is informal and is not assumed to have any particular taxonomic rank like the names authorized by the ICBN or the ICPN. The clade does not currently have a node-based definition.
Despite the intense combat, the Americans repulsed the Iraqis and continued to advance towards Kuwait City. Kuwaiti forces were tasked with liberating the city. Iraqi troops offered only light resistance. The Kuwaitis quickly liberated the city despite losing one soldier and having one plane shot down. On 27 February, Saddam ordered a retreat from Kuwait, and President Bush declared it liberated. However, an Iraqi unit at Kuwait International Airport appeared not to have received the message and fiercely resisted. US Marines fought for hours before securing the airport, after which Kuwait was declared secure. After four days of fighting, Iraqi forces were expelled from Kuwait. As part of a scorched earth policy, they set fire to nearly 700 oil wells and placed land mines around the wells to make extinguishing the fires more difficult.
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Sources: en.wikipedia.org
Cupuaçu trees usually range from 5–15 m (16–49 ft) in height, though some can reach 20 m (66 ft). They have brown bark, and the leaves range from 25–35 cm (9.8–13.8 in) long and 6–10 cm (2.4–3.9 in) across, with 9 or 10 pairs of veins. As the trees mature, the leaves change from pink-tinted to green, and eventually they begin bearing fruit. Flowers of cupuaçu are structurally complex, and require pollination from biotic vectors. The majority of cupuaçu trees are self-incompatible, which can result in decreased pollination levels, and consequently, a decrease in fruit yields. Pollination can also be negatively affected by environmental conditions. Pollinators, which include chrysomelid weevils and stingless bees, are unable to fly between flowers in heavy rains.
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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.
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.