A practical reference on tetrapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-07-29. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
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 whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
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.
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.
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.
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.
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Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also result in a musty smell and lighter skin. A baby born to a mother who has poorly treated PKU may have heart problems, a small head, and low birth weight. Phenylketonuria is an inherited genetic disorder. It is caused by mutations in the PAH gene, which can result in inefficient or nonfunctional phenylalanine hydroxylase, an enzyme responsible for the metabolism of excess phenylalanine. This results in the buildup of dietary phenylalanine to potentially toxic levels. It is autosomal recessive, meaning that both copies of the gene must be mutated for the condition to develop. The two main types are classic PKU and variant PKU, depending on whether any enzyme function remains. Those with one copy of a mutated gene typically do not have symptoms. Many countries have newborn screening programs for the disease. Treatment is with a diet low in foods that contain phenylalanine and includes special supplements. Babies should use a special formula with a small amount of breast milk. The diet should begin as soon as possible after birth and continue for life. People who are diagnosed early and maintain a strict diet can have normal health and a normal lifespan. Effectiveness is monitored through periodic blood tests. The medication sapropterin dihydrochloride may be useful in some. Phenylketonuria affects about one in 12,000 babies.
When Noriega created the PDF in 1983, he brought into its control Panama's customs and immigration apparatus, as well as the country's whole transportation network. This expansion of the military's role occurred simultaneously with a large growth in the cocaine trade, as well as in markets for weapons in various military conflicts in Central America. The profits the military reaped from these activities gave Noriega's military regime considerable financial clout. Noriega took control of most major newspapers by either buying a controlling stake in them or forcing them to shut down. The government also harassed, intimidated, or exiled individual journalists and editors. The newspaper La Prensa, which remained independent and was frequently critical of Noriega, had its staff intimidated and its offices damaged; eventually, it too was forced to close. In May 1984, Noriega allowed the first presidential elections in 16 years. Noriega and Díaz Herrera picked Nicolás Ardito Barletta Vallarino to be the PRD's candidate, with the intention of keeping him under close control. When the initial results showed Arias, who had the support of much of the opposition, on his way to a landslide victory, Noriega halted the count. After brazenly manipulating the results, the government announced that Barletta had won by a slim margin of 1,713 votes. Independent estimates suggested that Arias would have won by as many as 50,000 votes had the election been conducted fairly. More than 60,000 votes were not included in the final count.
=== Perforated === Perforated steel belts enable the drying media, for example hot air, to be transferred 'through' the belt, so that the air is in contact with all parts of the product on the belt. Normally, manufacturers offer perforated belts with five standard perforation patterns which cover most requirements. Other patterns, with a minimum hole diameter of 0.8 mm (0.03 in.) and different spacing, can be provided to suit specific applications.
On 29 March, an Israeli airstrike targeting Aleppo International Airport killed 38 Syrian soldiers, seven Hezbollah fighters and seven militiamen, in what became the deadliest Israeli strike on Syria in the past three years. Another airstrike in Bazouriyeh, Lebanon killed Ali Abed Akhsan Naim, the deputy commander of Hezbollah's rocket and missiles unit who the IDF said was responsible for planning attacks against Israeli civilians. On 30 March, Reuters reported that an Israeli strike had injured three UN observers and a translator who were monitoring hostilities along the Blue Line. An investigation by the Lebanese Army determined that the explosion was caused by a landmine, which Israel said was planted by Hezbollah. The IDF struck a centre of the Lebanese Ambulance Association at the end of March killing seven paramedics.
Sources: en.wikipedia.org
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Lilly's biosynthetic recombinant insulin, branded as Humulin, was introduced in 1983. In 1985, Axel Ullrich sequenced the human insulin receptor, further enhancing the understanding of insulin's biological mechanisms. By 1988, Novo Nordisk produced synthetic recombinant human insulin, which further improved insulin availability and consistency.
=== September 2008 === The European Parliament adopted a resolution on 3 September 2008, which noted that the large-scale war was preceded by Russian assistance to the separatists, as well as South Ossetian attacks against the Georgians. It also noted that the eventual Russian large-scale invasion followed "a long-term military build-up". In September 2008, Secretary of the National Security Council of Georgia Alexander Lomaia was asked by journalist why the Georgian authorities fell into Russian trap despite warnings from the United States, Lomaia suggested that Georgia had to avert the scenario of 1921. When again asked whether Georgia fell into a trap, he said that the Georgian government still regarded the situation in the same way as back then during the beginning of hostilities. In early September 2008, former Russian intelligence officer Boris Volodarsky said in an interview that he had information that Russian tanks had passed the Roki pass 20 minutes before the Georgian counterattack on Tskhinvali and Russia shelled Tskhinvali with the BM-21 Grads. In September 2008, economist Yegor Gaidar said that accomplished financial experts knew before the war that the war in the Caucasus was imminent after Kosovo and calculated how the war would impact the economics of Russia. On 9 September, Eric S.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.