This is a working overview of tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-01-18 and is reviewed periodically as new material appears.
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.
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.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four-residue sequence |
| Molar mass | About 390.35 g/mol | Free peptide, counter-ion not included |
| Appearance | White to off-white powder | Lyophilised solid from aqueous solution |
| Water solubility | Freely soluble | Short, polar peptide chain |
| Common synonyms | AEDG; epithalone | Catalogues use the names interchangeably |
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. It was designed at the St. Petersburg Institute of Bioregulation and Gerontology as a short, chemically defined analogue of epithalamin, a fraction obtained from bovine pineal tissue. Small peptide bioregulators of this type formed a long-running line of work there from the 1980s onward. Because the molecule is produced by solid-phase synthesis rather than extraction, its composition is exact and its purity can be measured directly.
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 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.
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Retinol is synthesized from the breakdown of β-carotene. First, the β-carotene 15,15'-monooxygenase cleaves β-carotene at the central double bond, creating an epoxide. This epoxide is then attacked by water creating two hydroxyl groups in the center of the structure. The cleavage occurs when these alcohols are oxidized to the aldehydes using NADH. This compound is called retinal. Retinal is then reduced to retinol by the enzyme retinol dehydrogenase. Retinol dehydrogenase is an enzyme that is dependent on NADH.
Sources: en.wikipedia.org
== Discovery == It is known that rapid heat hardening can be elicited by a brief exposure of cells to sub-lethal high temperature, which in turn provides protection from subsequent and more severe temperature. In 1962, Italian geneticist Ferruccio Ritossa reported that heat and the metabolic uncoupler 2,4-dinitrophenol induced a characteristic pattern of "puffing" in the chromosomes of Drosophila. This discovery eventually led to the identification of the heat-shock proteins (HSP) or stress proteins whose expression this puffing represented. Increased synthesis of selected proteins in Drosophila cells following stresses such as heat shock was first reported in 1974. In 1974, Tissieres, Mitchell and Tracy discovered that heat-shock induces the production of a small number of proteins and inhibits the production of most others. This initial biochemical finding gave rise to a large number of studies on the induction of heat shock and its biological role. Heat shock proteins often function as chaperones in the refolding of proteins damaged by heat stress. Heat shock proteins have been found in all species examined, from bacteria to humans, suggesting that they evolved very early and have an important function.
Phenylalkylpyrrolidines like PEP, MPEP, prolintane, α-PPP, α-PVP, pyrovalerone, and MDPV Phenylalkylpiperidines like AC927 (phenethylpiperidine), diphenidine, fentanyl, and ifenprodil Tetrahydroisoquinolines (THIQs) like anhalinine, pellotine, lophophorine, DOM-CR, nomifensine, tetrabenazine, and zelandopam Isoquinolines like perafensine, quinisocaine, and tilisolol Dihydroindoles and aminochromes like adrenochrome and adrenolutin 2-Aminoindanes (2-AIs) like 2-aminoindane, MDAI, MMAI, DOM-AI, and Pyr-AI 2-Aminotetralins (2-ATs) like 2-aminotetralin, MDAT, DOM-AT, 8-OH-DPAT, rotigotine, and UH-232 1-Aminomethylindanes (1-AMIs) like 2CB-Ind, AMMI, jimscaline, and bromojimscaline 3-Benzazepines like fenoldopam and lorcaserin Benzocyclobutenes (BCBs) like 2CBCB-NBOMe, S33005, TCB-2, tomscaline, and bromotomscaline 3-Aminochromans like CT-5126, 5-MeO-DPAC, robalzotan, and ebalzotan Benzoxepins like TFMBOX Phenylmethylpyrrolidines (benzylpyrrolidines) like APA-01 (PharmAla-1) 2-Benzylpiperidines and phenidates like 2-benzylpiperidine, methylphenidate, rimiterol, and DMBMPP Phenylcyclopropylamines like tranylcypromine, TMT, and DMCPA 3-Phenylpiperidines (3PIPs) like 3-phenylpiperidine, 3-PPP, OSU-6162 (PNU-96391), LPH-5, LPH-48, 2C-B-3PIP, 2C-B-3PIP-NBOMe, 2C-B-3PIP-POMe, and Z3517967757 (Z7757) 2-Phenylmorpholines like 2-phenylmorpholine, phenmetrazine, manifaxine, radafaxine, flumexadol, oxaflozane, and PF-219,061 Phenyloxazolamines or aminorex analogues like aminorex and pemoline Tricyclic compounds like benzoctamine and dizocilpine Ergolines and lysergamides like ergine (LSA) and LSD Partial ergolines and lysergamides like NDTDI, RU-27849, UCD0179, and UCD0120 Pyridopyrroloquinoxalines like lumateperone, IHCH-7113, IHCH-7086, and ITI-1549 Anthracenes like AMDA and SpAMDA Phenanthrenes like atherosperminine Aporphines like aporphine, apomorphine, glaucine, and nuciferine Others like 6-AB, 2-ADN, 2C-B-PYR, 2C-B-5-hemiFLY-α6 (BNAP), 2CB7 (2C-B-5-hemiFLY-β7), 2CBecca, 2CJP, 2CLisaB, 2CLisaH, 2-naphthylamine, AMMI, GYKI-52895, ivabradine, milnacipran, Org 6582, and ZC-B Some additional cyclized phenethylamines have also been described. Other related families that are not phenethylamines themselves include phenylpiperazines, benzylpiperazines, and 4-phenylpiperidines.
== See also == Houses of Parliament, Cape Town List of acts of the Parliament of South Africa Politics of South Africa List of legislatures by country List of committees of the Parliament of South Africa Provincial legislatures of South Africa
Sources: en.wikipedia.org
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.
The name derives from epithalamin, a pineal gland extract studied in the former Soviet Union. Researchers proposed that short fragments of that extract carried the biological activity of interest.
No major regulatory agency has approved it as a medicine. It is handled as a research chemical, and products sold under this name are not standardised drugs with defined clinical labelling.
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.