The short version of Certificate of analysis fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-01-18 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Often abbreviated AEDG in research literature |
| Common synonyms | Epithalon, epitalon, AEDG | Spelling variants refer to the same tetrapeptide |
| Molecular formula | C14H22N4O9 | Theoretical monoisotopic mass near 390.35 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Freely soluble in water | Hydrophilic peptide; dissolves in aqueous buffer |
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.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
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.
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.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
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.
== Further reading == Angeli S, Ceron F, Scaloni A, Monti M, Monteforti G, Minnocci A, et al. (1999). "Purification, structural characterization, cloning and immunocytochemical localization of chemoreception proteins from Schistocerca gregaria". Eur J Biochem. 262 (3): 745–54. doi:10.1046/j.1432-1327.1999.00438.x. PMID 10411636.
Seaborg was notified and the team left to sleep. Additional analysis and further experimentation showed the produced mendelevium isotope to have the expected mass of 256 and decay by electron capture to fermium-256 (half-life 157.6 minutes), the source of the observed fission.
Professor Richard Hilary Templer. Lately Director of Innovation, Grantham Institute, Imperial College London. For services to Climate Innovation. Dr. Gillian Romaine Tett. Editorial Board, Financial Times. For services to Economic Journalism. Usha Ladwa-Thomas. Race Adviser, Welsh Government. For services to Black, Asian and Minority Ethnic Communities. Margaret Ann Throup, MP. Member of Parliament for Erewash. For Political and Public Service. Jane Elizabeth Toogood. Co-Chair, Hydrogen Delivery Council. For services to the Low Carbon Hydrogen Sector. Sara Louise Tough. Executive Director, Children's Services, Norfolk County Council. For services to Education and Children's Social Care. John Henry Trayner. Lately Managing Director, Go-Ahead London. For services to Transport, to Skills and to Education in London. Marcus Edward Trescothick. Mental Health Ambassador, Professional Cricketers' Association. For services to Mental Ill Health. Professor Joyce Ann Tyldesley. Professor of Egyptology, University of Manchester. For services to Egyptology and Heritage. Nicola Madeline van der Drift. Chief Executive, International Bomber Command Centre. For services to Heritage. Louise van der Straeten. Senior Lawyer, Serious Fraud Office. For services to the Administration of Justice. Vinaichandra Guduguntla Venkatesham. Chief Executive Officer, Arsenal Football Club. For services to Sport. Ewan Andrew Venters. Chief Executive, Hauser & Wirth and Chair, GREAT Private Sector Council. For services to International Trade. Robert Iain Wainwright. Founder, Doddie Aid.
The 21st Century Cures Act enacted in December 2016 allows researchers to waive the requirement for informed consent when clinical testing "poses no more than minimal risk" and "includes appropriate safeguards to protect the rights, safety, and welfare of the human subject." The probability that a patient may sue researchers who utilize tissues that would typically be discarded is low, but as genetic research becomes more prevalent, this likelihood may increase. Ideally, researchers should obtain informed consent from individuals and aim for transparency in their intended use of the human tissue while protecting the privacy of the donor. CAP and other laboratory accreditation organizations (AO) have additional requirements and protocols for repurposing biospecimens that would otherwise be discarded. In July 2011, an Advance Notice of Proposed Rule Making (ANPRM), entitled "Human Subjects Research Protections: Enhancing Protections for Research Subjects and Reducing Burden, Delay, and Ambiguity for Investigators" was published in the Federal Register. The rise in direct-to-consumer (DTC) genetic testing has raised concerns about the secondary use of both patient samples and their data.
=== Phase 2 === 7-Oxoprasterone (7-keto-DHEA; HBL-9001; HL-9001; At-Ease) – undefined mechanism of action (immunomodulator) [4] [5] Amdiglurax (ALTO-100; NSI-189) – unknown mechanism of action (hippocampal neurogenesis stimulant and indirect brain-derived neurotrophic factor (BDNF) modulator) [6] [7] BI-1358894 – transient receptor potential cation channel TRPC4 and TRPC5 inhibitor [8] Cannabidiol (A-1002-N5S; CBD; Nantheia™) – cannabinoid, various actions [9] CORT-108297 (ADS-108297) – glucocorticoid receptor antagonist [10] Dronabinol (BX-1) – cannabinoid CB1 and CB2 receptor agonist [11] Iloperidone (Fanapt; Fanaptum; Fiapta; HP-873; ILO-522; VYV-683; Zomaril) – atypical antipsychotic (non-selective monoamine receptor modulator) [12] Ketamine intranasal (Ereska; PMI-100; PMI-150; SLS-002; TUR-002) – NMDA receptor antagonist and dissociative hallucinogen [13] Lithium cocrystal (AL-001; LiProSal; lithium salicylate/L-proline cocrystal) – undefined mechanism of action and mood stabilizer (improved formulation of lithium) [14] Methylone (MDMC; TSND-201) – serotonin–norepinephrine–dopamine releasing agent and entactogen Midomafetamine/citalopram (MDMA/citalopram) – serotonin–norepinephrine–dopamine releasing agent, weak serotonin 5-HT2 receptor agonist, and entactogen followed by a selective serotonin reuptake inhibitor Psilocybin (COMP-360; COMP360) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and psychedelic hallucinogen [15] Psilocybin (MYCO-001, MYCO-003) – non-selective serotonin receptor agonist, serotonin 5-HT2A receptor agonist, and psychedelic hallucinogen [16] Soclenicant (BNC-210; IW-2143) – α7-nicotinic acetylcholine receptor antagonist [17] SRX-246 (API-246) – vasopressin V1A receptor antagonist [18] Xenon (NBTX-001) – NMDA receptor antagonist [19]
Sources: en.wikipedia.org
Prior to the Apollo program (1968–1975), early space food development was conducted at the United States Air Force School of Aerospace Medicine and the Natick Army Labs. The variety of food options continued to expand for the Apollo missions, as the new availability of hot water made rehydrating freeze-dried foods simpler and produced a more appetizing result. This was an important aspect during the Apollo missions, since astronauts would be spending longer amounts of time in space. Appetizing foods would increase the crew's chances of maintaining proper nutrition, and the "spoon-bowl" allowed more normal eating practices. Food could be kept in special plastic zip-closure containers, and moisture allowed the food to stick to a spoon. However, the lack of taste was an issue at that time, as the food was prepared with very few spices to avoid overstimulating the gastrointestinal system. Thus, the astronauts were always looking for something that had a little more taste; Apollo 17 moonwalker Harrison Schmitt's favorite food was the bacon squares, while Buzz Aldrin enjoyed the shrimp and Paul J. Weitz went for the ice cream. In the later Apollo missions, foods were improved to make use of retort pouches and cans. This allowed the food to be thermally stabilized, enabling it to be stored for longer durations of time.
The acetolactate synthase (ALS) enzyme (also known as acetohydroxy acid or acetohydroxyacid synthase, abbr. AHAS) is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids (valine, leucine, and isoleucine).
is the density of the fluid at all points in the fluid. Bernoulli's equation and the Bernoulli constant are applicable throughout any region of flow where the energy per unit mass is uniform. Because the energy per unit mass of liquid in a well-mixed reservoir is uniform throughout, Bernoulli's equation can be used to analyze the fluid flow everywhere in that reservoir (including pipes or flow fields that the reservoir feeds) except where viscous forces dominate and erode the energy per unit mass. The following assumptions must be met for this Bernoulli equation to apply:
Field rations can be eaten at any temperature, but are preferably heated or cooked. However, as the use of cooking appliances or fire may be unavailable or tactically unwise, smokeless solid fuel and a portable stove are typically included in rations to heat meals. Hexamine fuel tablets have traditionally been preferred, though gelatinized ethanol is also sometimes used. Some modern field rations use a flameless ration heater instead of fuel tablets. NATO standardization states that, while main courses and entrées must be consumable without heating, main course components and hot beverages should be provided with a heater, with such items intended to be heated to a minimum temperature of 62 °C from an ambient temperature of 20 °C within 12 minutes.
Sources: en.wikipedia.org
88 percent of teleost species are gonochoristic, having individuals that remain either male or female throughout their adult lives. The sex of an individual can be determined genetically as in birds and mammals, or environmentally as in reptiles. In some teleosts, both genetics and the environment play a role in determining sex. For species whose sex is determined by genetics, it can come in three forms. In monofactorial sex determination, a single-locus determines sex inheritance. Both the XY sex-determination system and ZW sex-determination system exist in teleost species. Some species, such as the southern platyfish, have both systems and a male can be determined by XY or ZZ depending on the population. Multifactorial sex determination occurs in numerous Neotropical species and involves both XY and ZW systems. Multifactorial systems involve rearrangements of sex chromosomes and autosomes. For example, the darter characine has a ZW multifactorial system where the female is determined by ZW1W2 and the male by ZZ. The wolf fish has a XY multifactorial system where females are determined by X1X1X2X2 and the male by X1X2Y. Some teleosts, such as zebrafish, have a polyfactorial system, where there are several genes which play a role in determining sex. Environment-dependent sex determination has been documented in at least 70 species of teleost. Temperature is the main factor, but pH levels, growth rate, density and social environment may also play a role. For the Atlantic silverside, spawning in colder waters creates more females, while warmer waters create more males.
== Epidemiology == Diabulimia is most common in women, and in people between 15 and 30 years old. Around 40% of men with type 1 diabetes may have skipped insulin injection at least once, and around 20% of women. Some studies have found that up to 60% of people with type 1 diabetes deliberately restrict insulin at some point. Many articles and studies further conclude that diabetic females have, on average, higher body mass index (BMI) than their nondiabetic counterparts. Girls and young adult women with higher BMIs are also shown to be more likely to have disordered eating behavior (DEB). Many authoritative articles show that preteen and teenage girls with type 1 diabetes have significantly higher rates of eating disorders of all types than do girls without diabetes.
== High sensitivity variants of the biuret test == Two major modifications of the biuret test are commonly applied in modern colorimetric analysis of peptides: the bicinchoninic acid (BCA) assay and the Lowry assay. In these tests, the Cu+ formed during the biuret reaction reacts further with other reagents, leading to a deeper color. In the BCA test, Cu+ forms a deep purple complex with bicinchoninic acid (BCA), which absorbs around 562 nm, producing the signature mauve color. The water-soluble BCA/copper complex absorbs much more strongly than the peptide/copper complex, increasing the sensitivity of the biuret test by a factor of around 100: the BCA assay allows to detect proteins in the range of 0.0005 to 2 mg/mL. Additionally, the BCA protein assay gives the important benefit of compatibility with substances such as up to 5% surfactants in protein samples. In the Lowry protein assay, Cu+ is oxidized back to Cu2+ by MoVI in the Folin–Ciocalteu reagent, which forms molybdenum blue (MoIV). Tyrosine residues in the protein also form molybdenum blue under these circumstances. In this way, proteins can be detected in concentrations between 0.005 and 2 mg/mL. Molybdenum blue can in turn bind certain organic dyes such as malachite green and Auramine O, resulting in further amplification of the signal.
Access to safe drinking water and basic sanitation has deteriorated sharply over the course of the conflict. Studies link this to the bombing and the neglect of water networks and sewage infrastructure, together with the collapse of already fragile public utilities, which has left millions of people in the main cities without reliable and safe piped water or functioning wastewater treatment. In many towns and rural areas instead, families usually depend on groundwater pumped by diesel engines and on trucked water supplies, both of which require fuel that must be imported; during a period of complete closure of key ports in November 2017, humanitarian agencies estimated that around eight million people temporarily lost access to running water when fuel for pumps and distribution could not be procured.
The active Ras protein phosphorylates several proteins, along with the serine/threonine kinase, Raf. Raf in turn activates the MAPK cascade to facilitate ribosomal s6 kinase (RSK) activation and transcriptional regulation. Both Akt and RSK, components of the PI3K-Akt and MAPK pathways respectively, act to phosphorylate the cyclic AMP response element binding protein (CREB) transcription factor. Phosphorylated CREB translocates into the nucleus and mediates increased expression of anti-apoptotic proteins, thus promoting NGF-mediated cell survival. However, in the absence of NGF, the expression of pro-apoptotic proteins is increased when the activation of cell death-promoting transcription factors such as c-Jun are not suppressed by the aforementioned NGF-mediated cell survival pathways.
Sources: en.wikipedia.org
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.
No. Epithalamin is a peptide-rich extract prepared from bovine pineal glands, while epitalon is a short synthetic peptide designed as a defined analogue of it. The synthetic version was intended to provide a reproducible molecule with some of the same proposed biological activity.
Telomere elongation and telomerase activation have been reported in cultured human somatic cells, but evidence from living human subjects is limited and has not been independently confirmed at scale. Reported findings come largely from small studies with differing designs, so the question remains open rather than settled.
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.