tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-05-23 and is reviewed periodically as new material appears.
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 tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
| 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. 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.
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.
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.
==== Hypoxia/anoxia tolerance ==== Hypoxia/Anoxia tolerant ectotherms have shown unique strategies for surviving anoxia. Pond turtles, such as the painted turtle (Chrysemys picta bellii), will experience anoxia during winter while they overwinter at the bottom of frozen ponds. In their cardiac mitochondria, the reversing of Complex V, the usage of ATP, and the build-up of succinate are all prevented during anoxia. Crucian carps (Carassius carassius) also overwinter in frozen ponds and show no loss membrane potential in their cardiac mitochondria during anoxia, but this relies on complexes I and III to be active.
I Am Maximus ridden by Paul Townend wins the 2024 Grand National. Sunak condemns Iran's attack against Israel and says the UK is working to stabilise the situation. 14 April Sunak confirms that RAF fighter jets shot down "a number of drones" fired at Israel by Iran. Richard Lee, whose daughter Katrice Lee disappeared near a British military base in Paderborn, Germany, in 1981, says he will hand back his Army medals in protest at how the case was handled. Lawyers representing around 250 survivors of the Manchester Arena bombing confirm plans to take legal action against MI5. Charities supporting asylum seekers announce plans to launch legal challenges to moving people to Rwanda once legislation declaring it a safe country is passed in the coming days. The Duke of Kent confirms he is stepping down as Colonel of the Scots Guards after 50 years, and handing the role over to the Duke of Edinburgh. The UK experiences its warmest temperature of 2024 so far, with 21.8 °C recorded in the village of Writtle, near Chelmsford, Essex. 15 April Sunak urges "all sides" to "show restraint" after Iran's attack on Israel. A report by the Resolution Foundation calls for changes to Universal Credit to take into account an aging population with health problems. 16 April Figures show the rate of UK unemployment rose to 4.2% between December 2023 and March 2024, its highest level for six months. EasyJet cancels all flights to and from Tel Aviv for the whole of the summer, citing safety concerns following Iran's drone and missile attack on Israel.
A number of invertebrates have lung-like structures that serve a similar respiratory purpose to true vertebrate lungs, but are not evolutionarily related and only arise out of convergent evolution. Some arachnids, such as spiders and scorpions, have structures called book lungs used for atmospheric gas exchange. Some species of spider have four pairs of book lungs but most have two pairs. Scorpions have spiracles on their body for the entrance of air to the book lungs. The coconut crab is terrestrial and uses structures called branchiostegal lungs to breathe air. Juveniles are released into the ocean, however adults cannot swim and possess an only rudimentary set of gills. The adult crabs can breathe on land and hold their breath underwater. The branchiostegal lungs are seen as a developmental adaptive stage from water-living to enable land-living, or from fish to amphibian. Pulmonates are mostly land snails and slugs that have developed a simple lung from the mantle cavity. An externally located opening called the pneumostome allows air to be taken into the mantle cavity lung.
Sources: en.wikipedia.org
The grouping consistent with transfer of nitrogenous groups is EC 2.6. This includes enzymes like transaminase (also known as "aminotransferase"), and a very small number of oximinotransferases and other nitrogen group transferring enzymes. EC 2.6 previously included amidinotransferase but it has since been reclassified as a subcategory of EC 2.1 (single-carbon transferring enzymes). In the case of aspartate transaminase, which can act on tyrosine, phenylalanine, and tryptophan, it reversibly transfers an amino group from one molecule to the other. The reaction, for example, follows the following order: L-aspartate +2-oxoglutarate
=== Making use of the differences === The differences between the bacterial and eukaryotic ribosomes are exploited by pharmaceutical chemists to create antibiotics that can destroy a bacterial infection without harming the cells of the infected person. Due to the differences in their structures, the bacterial 70S ribosomes are vulnerable to these antibiotics while the eukaryotic 80S ribosomes are not. Even though mitochondria possess ribosomes similar to the bacterial ones, mitochondria are not affected by these antibiotics because they are surrounded by a double membrane that does not easily admit these antibiotics into the organelle. A noteworthy counterexample is the antineoplastic antibiotic chloramphenicol, which inhibits bacterial 50S and eukaryotic mitochondrial 50S ribosomes. Ribosomes in chloroplasts, however, are different: Antibiotic resistance in chloroplast ribosomal proteins is a trait that has to be introduced as a marker, with genetic engineering.
The glans penis is a body of spongy erectile tissue that is moulded on the rounded ends of the two corpora cavernosa penis, extending farther on their upper than on their lower surfaces. It is the expanded cap of the corpus spongiosum, a sponge-like region that surrounds the male urethra within the penis maintaining it as a viable channel for ejaculation. The glans is covered by a stratified squamous epithelium and a dense layer of connective tissue equivalent to the dermis of typical skin. The papillary layer of the dermis blends into the dense connective tissue forming the tunica albuginea of the corpus spongiosum behind the glans. The external lining with mucosal tissue is responsible for its typical smooth texture and appearance. The increase of arterial flow during erection fills the erectile tissue with blood, causing the glans to grow in size and sensitivity. While the penis is rigid when erect, the glans itself remains slightly softer. The soft cushiony texture of the glans absorbs impact during rigorous instances of copulation. The proportional size of the glans penis can vary among males. While the shape of the glans is typically acorn-like, in some men it might be wider in circumference than the shaft, giving the penis a mushroom-like appearance, while in others it might be narrower and more akin to a probe in shape. The reason for the shape of the glans is uncertain. Some researchers suggest that it evolved to be acorn-, mushroom-, or cone-shaped, allowing it to remove any semen from previous sexual partners during copulation.
Sources: en.wikipedia.org
Baseball steak is a center cut of beef taken from the top sirloin cap steak. Baseball steaks differ from sirloin steaks in that the bone and the tenderloin and bottom round muscles have been removed; and the cut is taken from gluteus medius: baseball steak is essentially a center cut top sirloin steak. This cut is very lean, and is considered very flavorful. The IMPS/NAMP codes for this subprimal cut are 181A and 184: 181A is obtained from 181 after removing the bottom sirloin and the butt tender (the part of the tenderloin which is in the sirloin); 184 is obtained from 182 after removing the bottom sirloin. The foodservice cuts from 184 are 184A through 184F, its portion cut is 1184 and, the "subportion" cuts from 1184 are 1184A through 1184F. 181A is not further divided into foodservice cuts. Baseball steaks are made primarily from cut 184F. In Australia, this cut is called D-rump in the Handbook of Australian Meat and assigned code 2100.
Serbs = 6,142,070 (72.7%) Albanians = 984,761 (11.66%) Hungarians = 430,314 (5.10%) Croats = 184,913 (2.19%) ethnic Muslims = 154,330 (1.83%) ethnic Yugoslavs = 123,824 (1.47%) Slovaks = 76,733 (0.82%) Romanians (self-declared) = 57,419 (0.62%) Bulgarians = 53,800 (0.58%) Romani = 49,894 (0.54%) Macedonians = 42,675 (0.46%) Rusyns = 20,608 (0.22%) Turks = 18,220 (0.20%) Slovenes = 15,957 (0.17%) "Vlachs" (Romanians) = 14,724 (0.16%)
== Education and early career == Tew earned a Bachelor of Science in Microbiology/Genetics from the University of Wales, Swansea in 1973 and a PhD in Biochemical Pharmacology from the University of London, where he also received postdoctoral training in 1976. He served as the Head of the Basic Pharmacology Program at the Lombardi Cancer Center from 1982 to 1985, when he became a member and later Chairman of Pharmacology at the Fox Chase Cancer Center. Concurrently, he worked as an Adjunct Associate Professor of Pharmacology at the University of Pennsylvania until 1990 and was awarded his DSc from the University of London in 1995.
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.
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.