AEDG comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-01-09. Numbers and descriptions here follow the published literature rather than marketing 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.
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.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
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.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
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.
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.
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.
A review of four studies on the effectiveness of mindfulness-based cognitive therapy (MBCT), a recently developed class-based program designed to prevent relapse, suggests that MBCT may have an additive effect when provided with the usual care in patients who have had three or more depressive episodes, although the usual care did not include antidepressant treatment or any psychotherapy, and the improvement observed may have reflected non-specific or placebo effects. Of note, although Mindfulness-based cognitive therapy for depression prevented relapse of future depressive episodes, there is no research on whether it can cause the remission of a current depressive episode. Interpersonal psychotherapy (IPT) focuses on the social and interpersonal triggers that may cause depression. There is evidence that it is an effective treatment for depression. Here, the therapy takes a fairly structured course (often 12 sessions, as in the original research versions) as in the case with CBT; however, the focus is on relationships with others. Unlike family therapy, IPT is an individual format, so it is possible to work on interpersonal themes even if other family members do not come to the session. Therapy can be used to help a person develop or improve interpersonal skills in order to allow him or her to communicate more effectively and reduce stress. In a meta-analysis of 16 studies and 4,356 patients, the average improvement in depressive symptoms was an effect size of d = 0.63 (95% CI, 0.36 to 0.90).
=== Education === Al-Fawzan enrolled in the public school in Ash-Shamasiyyah in 1950 (1369 AH). He completed his education at Al-Faysaliyyah School in Buraydah in 1952 (1371 AH), and was appointed as a primary school teacher. He then enrolled at the Ma'had Al-'Ilmī (The Institute of Knowledge) in Buraydah when it opened in 1954 (1373 AH), and graduated from it in 1958 (1377 AH). He joined the Kullīyat Ash-Sharīʿah (The College of Sharīʿah) in Riyadh and graduated in 1962 (1381 AH). Al-Fawzan later obtained a master’s degree in fiqh in the field of inheritance law, with a thesis titled: "Al-Taḥqīqāt Al-Marḍiyyah fī Al-Mabāḥith Al-Farḍiyyah" (A Satisfactory investigation into the issues of obligatory Shares in Inheritance). He subsequently obtained a doctorate in fiqh from the same college, with a dissertation titled: "Aḥkām Al-Aṭʿimah fī Al-Sharīʿah Al-Islāmiyyah" (The Rulings of Foods in the Islamic Sharīʿah).
== Coordination properties == The conjugate base of DTPA has a high affinity for metal cations. Thus, the penta-anion DTPA5− is potentially an octadentate ligand assuming that each nitrogen centre and each –COO− group acts as a centre for coordination. The formation constants for its complexes are about 100 greater than those for EDTA. As a chelating agent, DTPA wraps around a metal ion by forming up to eight bonds. Its complexes can also have an extra water molecule that coordinates the metal ion. Transition metals, however, usually form less than eight coordination bonds. So, after forming a complex with a metal, DTPA still has the ability to bind to other reagents, as is shown by its derivative pendetide. For example, in its complex with copper(II), DTPA binds in a hexadentate manner utilizing the three amine centres and three of the five carboxylates. The word "DTPA" may sometimes denote DTPA5−. For explicit disambiguation, one can write H5DTPA as opposed to DTPA5−.
Cresswell and co-workers first discovered tapasin (TAP-associated glycoprotein) as a 48 kDa protein in complexes isolated with TAP1 antibodies from digitonin lysates of human B lymphoblastoid cells. Tapasin binds HC/β2m along with ER chaperones to the peptide transporter. It is located in the ER and its function comprises holding together class I molecules jointly with the chaperone calreticulin and the ERp57 to TAP. Studies of a tapasin-deficient cell line and from mice bearing a disrupted tapasin gene, the short-lived complex of class I molecules. Tapasin and TAP are very important for the stabilization of the class I molecules and also for the optimization of the peptide presented to cytotoxic T cells. A PLC-independent tapasin homologue protein named TAPBPR was found that has the ability to act as a second MHC-I specific peptide proofreader or editor, but does not possess a transmembrane domain. Tapasin and TAPBPR share similar binding interfaces on MHC-I, as shown with the X-ray structure of TAPBPR with MHC-I (heavy chain and β2 microglobulin). The use of a photo-cleavable high-affinity peptide allowed researchers to form a stable (bound) MHC-I molecules and afterwards to form a stable TAPBPR and MHC-I complex with cleavage by UV light of the photoinduced peptide.
== Pharmacology == Pirepemat shows affinity for several neurotransmitter receptors and transporters. These include the serotonin 5-HT7 receptor (Ki = 980 nM), the sigma σ1 receptor (Ki = 1,200 nM), the serotonin transporter (SERT) (Ki = 2,500 nM), the α2C-adrenergic receptor (Ki = 3,800 nM), the α2A-adrenergic receptor (Ki = 6,500 nM), the serotonin 5-HT2C receptor (Ki = 6,600 nM), the serotonin 5-HT2A receptor (Ki = 8,100 nM), and the norepinephrine transporter (NET) (Ki = 8,100 nM). It also shows affinity for the rat κ-opioid receptor (KOR) (Ki = 6,500 nM) and has weak affinity for the α1-adrenergic receptor (Ki = 21,000 nM). The drug was an antagonist or inhibitor at all assessed targets (which included some but not all of the preceding sites). Pirepemat has been described as a "cortical enhancer" and has been reported to region-specifically increase norepinephrine, dopamine, and acetylcholine levels in the cerebral cortex. Serotonin 5-HT7 receptor antagonism and α2-adrenergic receptor antagonism were hypothesized to underlie these effects. In animals, pirepemat has been found to reverse hypoactivity induced by the dopamine depleting agent tetrabenazine whilst not increasing basal locomotor activity and not affecting or minimally influencing dextroamphetamine- and dizocilpine-induced locomotor hyperactivity.
Sources: en.wikipedia.org
=== Purification === There are several methods for purifying and isolating honokiol. In nature, honokiol exists with its structural isomer magnolol, which differs from honokiol only by the position of one hydroxyl group. Because of the very similar properties of magnolol and honokiol, purification has often been limited to a HPLC or electromigration. However, methods developed in 2006 by workers in the lab of Jack L. Arbiser, took advantage of the proximity of the phenolic hydroxyl groups in magnolol, which form a protectable diol, to generate a magnolol acetonide (Figure 1), with a subsequent simple purification via flash chromatography over silica. Figure 1
They develop games through playtesting and iteration, describing game design as a kind of experimental psychology. By 2012, Valve employed around 250 people and was reportedly worth over US$3 billion. Most of Valve's revenue comes from Steam, which controlled over half of the digital PC games market in 2011 and generated an estimated $3.4 billion in 2017.
Each part of the digestive system is subject to a wide range of disorders many of which can be congenital. Mouth diseases can also be caused by pathogenic bacteria, viruses, fungi and as a side effect of some medications. Mouth diseases include tongue diseases and salivary gland diseases. A common gum disease in the mouth is gingivitis which is caused by bacteria in plaque. The most common viral infection of the mouth is gingivostomatitis caused by herpes simplex. A common fungal infection is candidiasis commonly known as thrush which affects the mucous membranes of the mouth. There are a number of esophageal diseases such as the development of Schatzki rings that can restrict the passageway, causing difficulties in swallowing. They can also completely block the esophagus. Stomach diseases are often chronic conditions and include gastroparesis, gastritis, and peptic ulcers. A number of problems including malnutrition and anemia can arise from malabsorption, the abnormal absorption of nutrients in the GI tract. Malabsorption can have many causes ranging from infection, to enzyme deficiencies such as exocrine pancreatic insufficiency. It can also arise as a result of other gastrointestinal diseases such as coeliac disease. Coeliac disease is an autoimmune disorder of the small intestine. This can cause vitamin deficiencies due to the improper absorption of nutrients in the small intestine. The small intestine can also be obstructed by a volvulus, a loop of intestine that becomes twisted enclosing its attached mesentery. This can cause mesenteric ischemia if severe enough.
By failing to close on the enemy earlier and more forcefully, his critics argue, he squandered an opportunity to destroy the entire Japanese Mobile Fleet. "This is what comes of placing a non-aviator in command over carriers" was the common refrain. Admiral John Towers, a naval aviation pioneer and Deputy Commander-in-Chief Pacific Fleet, demanded that Spruance be relieved. The request was denied by Nimitz. Moreover, Spruance was supported in his decision by Admiral Kelly Turner and Admiral Ernest King, Chief of Naval Operations. Spruance's caution (in particular, his suspicion of a diversionary force) can be compared with Admiral William Halsey's headlong pursuit of an actual diversionary force at Leyte Gulf four months later. Halsey left the American invasion fleet weakly protected during the Battle off Samar, nearly resulting in a devastating attack on the landing force by Japanese heavy surface units. It was prevented only by the heroic and desperate attack of 5 small American surface ships, which put up such an intense fight that the 23-ship-strong Japanese fleet thought they were engaging a much larger force and withdrew. In addition, by focusing on defense first, the carrier forces under Spruance at Philippine Sea suffered no significant harm. This was in contrast to Leyte Gulf when Halsey's carriers were trying to neutralize the enemy airfields and attack the enemy fleet simultaneously, such that a Japanese bomber managed to evade the Combat Air Patrols to fatally cripple the light carrier USS Princeton. Likewise, during the carrier-based air raids, U.S.
Sources: en.wikipedia.org
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.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.