AEDG is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
| 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 |
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.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
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.
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.
Enzyme kinetics is the scientific study of chemical reactions caused by enzyme catalysis, and a subfield of biochemistry. It is concerned with the reaction rate of chemical reactions, their effects, and the varying conditions that cause the reactions. Studying an enzyme's kinetics in this way can reveal the catalytic reaction mechanism of this enzyme, its role in metabolism, how its activity is controlled, and how a drug or a modifier (inhibitor or activator) might affect the rate. An enzyme, often written "E" in reactions, is a protein molecule that serves as a biological catalyst to facilitate and accelerate a chemical reaction in a cell or other biological environment. It does this through binding of one or more other molecules, its substrate (S), which the enzyme acts upon to form the desired product. The substrate binds to the active site of the enzyme to produce an enzyme-substrate complex (ES), and is transformed into an enzyme-product complex (EP) and from there to the product or products (P), via a transition state (ES*). That series of steps is known as the mechanism:
A trachea may be narrowed or compressed, usually a result of enlarged nearby lymph nodes; cancers of the trachea or nearby structures; large thyroid goitres; or rarely as a result of other processes such as unusually swollen blood vessels. Scarring from tracheobronchial injury or intubation; or inflammation associated with granulomatosis with polyangiitis may also cause a narrowing of the trachea (tracheal stenosis). Obstruction invariably causes a harsh breathing sound known as stridor. A camera inserted via the mouth down into the trachea, called bronchoscopy, may be performed to investigate the cause of an obstruction. Management of obstructions depends on the cause. Obstructions as a result of malignancy may be managed with surgery, chemotherapy or radiotherapy. A stent may be inserted over the obstruction. Benign lesions, such as narrowing resulting from scarring, are likely to be surgically excised. One cause of narrowing is tracheomalacia, which is the tendency for the trachea to collapse when there is increased external pressure, such as when airflow is increased during breathing in or out, due to decreased compliance. It can be due to congenital causes, or due to things that develop after birth, such as compression from nearby masses or swelling, or trauma. Congenital tracheomalacia can occur by itself or in association with other abnormalities such as bronchomalacia or laryngomalacia, and abnormal connections between the trachea and the oesophagus, amongst others.
=== Drug withdrawal === Phenobarbital is sometimes used for alcohol detoxification and benzodiazepine detoxification for its sedative and anticonvulsant properties. The benzodiazepines chlordiazepoxide (Librium) and oxazepam (Serax) have largely replaced phenobarbital for detoxification.
Although very common, nipple pain and nipple trauma (cracking, open sores) should not be normalized, as these are often signs of a shallow latch or other underlying problem that can be evaluated and fixed. In addition to shallow latch, other causes of nipple pain include, but are not limited to, skin infection or inflammation, blood vessel spasm or the equivalent of Raynaud Syndrome in the breast, mastitis, plugged ducts, and nipple blebs. Pain caused by a problem deep in the breast may also present with nipple pain due to the paths of nerves in the breast. In addition to the serious nature of many of these causes, nipple pain is a common reason for a mother stopping breastfeeding, so mothers experiencing nipple pain must be evaluated.
Smart TG, Stephenson FA (2019). "A half century of γ-aminobutyric acid". Brain Neurosci Adv. 3 2398212819858249. doi:10.1177/2398212819858249. PMC 7058221. PMID 32166183. Parviz M, Vogel K, Gibson KM, Pearl PL (2014-11-25). "Disorders of GABA metabolism: SSADH and GABA-transaminase deficiencies". Journal of Pediatric Epilepsy. 3 (4): 217–227. doi:10.3233/PEP-14097. PMC 4256671. PMID 25485164. Clinical disorders known to affect inherited GABA metabolism Gamma-aminobutyric acid MS Spectrum Scholarpedia article on GABA List of GABA neurons on NeuroLex.org Effects of Oral Gamma-Aminobutyric Acid (GABA) Administration on Stress and Sleep in Humans: A Systematic Review
Sources: en.wikipedia.org
=== Betaines and similar compounds === The compound trimethylglycine, named as "betaine", contain the same structural motif, a quaternary nitrogen atom with a carboxylate group attached to it via a –CH2– link. All compounds whose structure includes this motif are known as betaines. Betaines do not isomerize because the chemical groups attached to the nitrogen atom are not labile. These compounds may be classed as permanent zwitterions, as isomerisation to a molecule with no electrical charges does not occur, or is very slow. Other examples of permanent zwitterions include phosphatidylcholines, which also contain a quaternary nitrogen atom, but with a negatively-charged phosphate group in place of a carboxylate group; sulfobetaines, which contain a quaternary nitrogen atom and a negatively charged sulfonate group; and pulmonary surfactants such as dipalmitoylphosphatidylcholine. Lauramidopropyl betaine is the major component of cocamidopropyl betaine.
Heseltine was disappointed not to receive the support of old allies on the second ballot; these included Secretary of State for Defence Tom King (whom he asked in vain to second his nomination, but who was angry at a leadership contest when British troops were soon to go to war in Kuwait and supported Douglas Hurd), Cecil Parkinson and Norman Lamont (who managed John Major's campaign). Over the weekend on 24–25 November, many Conservative MPs were faced with the anger of their local party members who overwhelmingly supported Thatcher but did not at that time have a vote in leadership elections, and opinion polls showed that chancellor John Major would also boost Conservative support if leader (previously Heseltine's unique selling-point). Heseltine had never done much to court support among younger MPs the way Major had, and was seen as aloof even by his own supporters. In the second ballot, a week after the first, Heseltine's vote actually fell to 131 (just over 35%) as some MPs had voted for him in the first ballot as a protest against or to try to oust Thatcher but preferred to vote for other candidates now that they had a wider choice. John Major, with 185 votes, was only two votes short of an overall majority. Heseltine immediately and publicly conceded defeat, announcing that he would vote for Major if the third ballot went ahead (it did not, as Hurd, who had finished a distant third, also conceded).
American biochemist at the University of Medicine and Dentistry of New Jersey, known for his discovery of sodium-glucose cotransport. Francis Crick FRS (1916–2004). British molecular biologist and neuroscientist at the University of Cambridge and the Salk Institute, noted for proposing the double helical structure of DNA. Foreign associate Natl. Acad. Sci. USA. Pedro Cuatrecasas (1936–2025). American biochemist at UC San Diego, known for the development of affinity chromatography. Member Natl. Acad. Sci. USA. Richard D. Cummings (20th–21st century). American biologist at Harvard, known for studying pathways of glycoconjugate biosynthesis and alterations in biosynthesis in human and animal diseases. Anthony Czarnik (b. 1957). American chemist and inventor known for pioneering studies in the field of fluorescent chemosensors.
Co-administration with strong inhibitors of the liver enzyme CYP3A4 (e.g. ketoconazole, ritonavir, clarithromycin, grapefruit juice) may increase pazopanib serum levels as it is a CYP3A4 substrate. CYP3A4 inducers (e.g. rifampin, carbamazepine) decrease pazopanib serum levels. It is a p-glycoprotein (PGP) substrate and hence PGP inhibitors such as quinidine may interact with pazopanib. Pazopanib is not a substrate for either of the liver enzymes OATP1B1 and OATP1B3. Pazopanib has inhibitory potency towards OATP1B1 but not for OATP1B3.
Sources: en.wikipedia.org
==== Barth syndrome ==== Barth syndrome is a rare genetic disorder that was recognised in the 1970s to cause infantile death. It has a mutation in the gene coding for tafazzin, an enzyme involved in the biosynthesis of cardiolipin. Tafazzin is an indispensable enzyme to synthesize cardiolipin in eukaryotes involved in the remodeling of CL acyl chains by transferring linoleic acid from PC to monolysocardiolipin. Mutation of tafazzin would cause insufficient cardiolipin remodeling. However, it appears that cells compensate and ATP production is similar or higher than normal cells. Females heterozygous for the trait are unaffected. Sufferers of this condition have mitochondria that are abnormal. Cardiomyopathy and general weakness is common to these patients.
== Clinical significance == Gastroesophageal reflux disease (GERD) is a common disorder that occurs when stomach acid repeatedly flows back into the esophagus, this backwash of acid (reflux) also known as heartburn can irritate the lining of the esophagus. Most people are able to manage the discomfort of GERD with lifestyle changes and medications, notably proton pump inhibitors, and H2 blockers. Antacids may also be used to neutralise gastric acid. Sometimes, surgery may be needed to ease symptoms. Chronic inflammation of the gastric mucosa can lead to atrophic gastritis resulting in a decreased secretion of gastric acid, and consequent digestive problems. In hypochlorhydria and achlorhydria, gastric acid is either low or absent, respectively. This can potentially lead to less protection against ingested pathogens such as Vibrio or Helicobacter bacteria. In Zollinger–Ellison syndrome gastrin levels are increased, leading to excess gastric acid production, which can cause gastric ulcers. Hypercalcemia also increases gastrin and gastric acid and can cause ulcers. In diseases featuring excess vomiting, hypochloremic metabolic alkalosis (decreased blood acidity by H+ and chlorine depletion) may develop.
The HEVC encoder has 17 3G-SDI inputs and uses 17 boards for parallel processing with each board encoding a row of 7680 × 256 pixels to allow for real time video encoding. The HEVC encoder is compliant with draft 4 of the HEVC standard and has a maximum bit rate of 340 Mbit/s. The HEVC encoder was shown at the NHK Science & Technology Research Laboratories Open House 2013 that took place from May 30 to June 2. At the NHK Open House 2013 the HEVC encoder used a bit rate of 85 Mbit/s, which gives a compression ratio of 350∶1. On May 21, 2013, Microsoft announced the Xbox One, which supports 4K resolution (3840 × 2160) video output and 7.1 surround sound. Yusuf Mehdi, corporate vice president of marketing and strategy for Microsoft, has stated that there is no hardware restriction that would prevent Xbox One games from running at 4K resolution. On May 30, 2013, Eye IO announced that their encoding technology was licensed by Sony Pictures Entertainment to deliver 4K Ultra HD video. Eye IO encodes their video assets at 3840 × 2160 and includes support for the xvYCC color space. In mid-2013, a Chinese television manufacturer produced the first 50-inch UHD television set costing less than $1,000. On June 11, 2013, Comcast announced that they had demonstrated the first public U.S.-based delivery of 4K Ultra HD video at the 2013 NCTA show. The demonstration included segments from Oblivion, Defiance, and nature content sent over a DOCSIS 3.0 network.
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.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.