Aspartimide 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.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
Identity is normally established by reversed-phase high-performance liquid chromatography combined with mass spectrometry, a pairing that separates components and confirms molecular mass at once. Purity is quoted as a percentage from the chromatogram, and figures above ninety-five percent are a frequent commercial specification. Amino acid analysis or sequencing supplies further confirmation when required. Because many short peptides behave similarly under chromatography, retention time alone does not establish sequence; the mass measurement is what separates one tetrapeptide from another, and certificates should report both.
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.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
| Property | Value | Notes |
|---|---|---|
| Sequence | Ala-Glu-Asp-Gly | Written in three-letter amino acid code |
| Single-letter code | AEDG | Form used in most catalogue entries |
| Typical purity specification | 95 percent or higher | Value read from the HPLC chromatogram |
| Storage, dry solid | Minus 20 degrees Celsius, desiccated | Sealed container, protected from light |
| Handling, solution | Divide into single-use portions | Limits losses from freeze-thaw cycling |
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.
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.
27 March – A report clears Conservative MP Bernard Jenkin of breaching COVID-19 laws over his attendance at a "wine and nibbles" event on the Parliamentary estate in December 2020, which the report describes as socially-distanced with "business and social elements". 28 March – Keir Starmer and Angela Rayner launch Labour's campaign for the 2024 United Kingdom local elections at an event in Dudley. Honours are conferred on businessman and senior Conservative Party treasurer Mohamed Mansour, Farming Minister Mark Spencer and Shipley MP Philip Davies, all of who receive knighthoods, while former ministers Tracey Crouch and Harriett Baldwin are awarded damehoods. The announcement comes as part of an honours list published at the start of the Parliamentary recess. The Assisted Dying for Terminally Ill Adults (Scotland) Bill, a bill to legalise assisted dying in Scotland and drafted by Liberal Democrat MSP Liam McArthur, is introduced into the Scottish Parliament. 29 March – Sir Jeffrey Donaldson resigns as leader of the Democratic Unionist Party after being charged with rape and other historical sexual offences. Gavin Robinson is appointed interim leader until a new leader can be elected. 30 March – First Minister of Northern Ireland Michelle O'Neill says she is determined the Stormont Assembly and Executive will continue to function following the resignation of Jeffrey Donaldson as DUP leader. 31 March – The UK government says it will work alongside the Northern Ireland Executive to maintain stability at Stormont.
The definition of whistleblowing in force under the "Sapin 2 Law" – which includes whistleblowing not based on work – has been maintained. The protection applies to any natural person who facilitates or assists whistleblowers – as required in the directive – but also to entities such as NGOs (Non-governmental organizations) or trade unions, which act as a facilitator. They are offered the same level of protection. Military personnel will now be afforded the same level of protection as other civil servants, so long as they do not disclose information that may harm national security. The law provides that whistleblowers may be granted financial assistance when subjected to a suit, by making an application to a judge, who has the power to force the suing organization – the employer, for instance – to cover their legal fees and, if their financial situation has deteriorated, their living expenses. The law provides that whistleblowers shall not incur criminal liability with respect to the acquisition of, or access to, the information that is reported or publicly disclosed. They cannot be sentenced for any offenses committed to gather proof or information as long as they obtained it lawfully. The law strengthens existing sanctions against those who retaliate against whistleblowers: The criminal sanctions applicable to persons retaliating against whistleblowers can go up to three years of imprisonment and a fine of €45,000. The judges may impose €60,000 fines on companies taking a SLAPP action against a whistleblower.
Nickel-48, discovered in 1999, is the most neutron-poor nickel isotope known. With 28 protons and 20 neutrons 48Ni is "doubly magic" (like 208Pb) and therefore much more stable, with a half-life around 3 milliseconds, than would be expected from its position in the chart of nuclides. It has the highest ratio of protons to neutrons (proton excess) of any known doubly magic nuclide.
=== Keith Jackson === A 1989 Washington Post investigative story accused the administration of setting up an 18-year-old black man from Baltimore in a sting operation to showcase the drug problem close to home. The DEA, using an undercover agent, pushed a black 18-year-old high school student, Keith Jackson, to make a sale of crack outside the White House. (Jackson had already sold cocaine to agents on four other occasions.) In a recorded conversation with the agents, Jackson can be heard saying "Where the [Expletive] is the White House?" The agents set up a buy with Jackson in Lafayette Park, just across the street from the White House. Jackson was arrested and convicted of felony possession of crack cocaine with intent to distribute. He had no prior convictions but was sentenced to 10 years in prison based on the mandatory minimum laws of 1988. After his conviction, Jackson was visibly in tears. U.S. District Judge Stanley Sporkin told Jackson at his sentencing, "Bush used you, in the sense of making a big drug speech. But he's a decent man, a man of great compassion. Maybe he can find a way to reduce at least some of that sentence." Bush, when asked about the story, told the Washington Post, "The man went there and sold drugs in front of the White House, didn't he?... I can't feel sorry for this fellow."
== Academic achievements == In 1942, Drew became the first African-American surgeon selected to serve as an examiner on the American Board of Surgery. Drew had a lengthy research and teaching career, returning to Freedman's Hospital and Howard University as a surgeon and professor of medicine in 1942. He was awarded the Spingarn Medal by the NAACP in 1944 for his work. He was given honorary doctor of science degrees by Virginia State College in 1945 and by Amherst College in 1947.
Sources: en.wikipedia.org
=== Electronation and de-electronation === The electrochemist John Bockris proposed the words electronation and de-electronation to describe reduction and oxidation processes, respectively, when they occur at electrodes. These words are analogous to protonation and deprotonation. IUPAC has recognized the terms electronation and de-electronation.
== Degradation == When a serpin inhibits a target protease, it forms a permanent complex, which needs to be disposed of. For extracellular serpins, the final serpin-enzyme complexes are rapidly cleared from circulation. One mechanism by which this occurs in mammals is via the low-density lipoprotein receptor-related protein (LRP), which binds to inhibitory complexes made by antithrombin, PAI-1, and neuroserpin, causing cellular uptake. Similarly, the Drosophila necrotic serpin is degraded in the lysosome after being trafficked into the cell by the Lipophorin Receptor-1 (homologous to the mammalian LDL receptor family).
=== Column === The column used for GPC is filled with a microporous packing material. The column is filled with the gel. Since the total penetration volume is the maximum volume permeated by the analytes, and there is no retention on the surface of the stationary phase, the total column volume is usually large, relatively to the sample volume.
== Discovery == In 1902, Léon Teisserenc de Bort from France and Richard Assmann from Germany, in separate but coordinated publications and following years of observations, published the discovery of an isothermal layer at around 11–14 km (6.8-8.7 mi), which is the base of the lower stratosphere. This was based on temperature profiles from mostly unmanned and a few manned instrumented balloons.
=== ColdFusion MX 7 === With the release of ColdFusion 7.0 on February 7, 2005, the naming convention was amended, rendering the product name "Macromedia ColdFusion MX 7" (the codename for CFMX7 was "Blackstone"). CFMX 7 added Flash-based and XForms-based web forms, and a report builder that output in Adobe PDF as well as FlashPaper, RTF and Excel. The Adobe PDF output is also available as a wrapper to any HTML page, converting that page to a quality printable document. The enterprise edition also added Gateways. These provide interaction with non-HTTP request services such as IM Services, SMS, Directory Watchers, and an asynchronous execution. XML support was boosted in this version to include native schema checking. ColdFusion MX 7.0.1 (codename "Merrimack") added support for Mac OS X, improvements to Flash forms, RTF support for CFReport, the new CFCPRoxy feature for Java/CFC integration, and more. ColdFusion MX 7.0.2 (codenamed "Mystic") included advanced features for working with Adobe Flex 2 as well as more improvements for the CF Report Builder.
Sources: en.wikipedia.org
The β and γ phases are obtained by annealing the most stable α-Al2S3 phase at several hundred degrees Celsius. Compressing aluminum sulfide to 2–65 bar results in the δ phase where vacancies are arranged in a superlattice of tetragonal symmetry. Unlike Al2O3, in which the Al(III) centers occupy octahedral holes, the more expanded framework of Al2S3 stabilizes the Al(III) centers into one third of the tetrahedral holes of a hexagonally close-packed arrangement of the sulfide anions. At higher temperature, the Al(III) centers become randomized to give a "defect wurtzite" structure. And at still higher temperatures stabilize the γ-Al2S3 forms, with a structure akin to γ-Al2O3. Molecular derivatives of Al2S3 are not known. Mixed Al-S-Cl compounds are however known. Al2Se3 and Al2Te3 are also known.
The Parliamentary Commission on Standards finds that Lord Waheed Alli committed four minor breaches in the register of members' interests. 24 October – Chancellor Rachel Reeves announces the UK government is to change its self-imposed debt rules in order to make an extra £50bn available for spending at the forthcoming budget. Lee Waters announces he will step down from the Senedd at the 2026 election. 26 October – Commonwealth leaders agree the "time has come" for a conversation about reparations for the slave trade, despite the UK's wish to keep the topic off the agenda at the Commonwealth Heads of Government Meeting. Buckingham Palace announces that Charles III is expected to return to a "normal" schedule in 2025 after his trip to the Commonwealth summit proved to be a "perfect tonic". A video emerges that appears to show Mike Amesbury, the MP for Runcorn and Helsby, shouting and swearing at a man who is lying on the ground during an apparent disturbance. Secretary of State for Wales Jo Stevens is accused by the Conservatives of bringing her office into disrepute after recording a political interview on its premises, something which they say breaches the civil service code. 28 October – The speaker of the House of Commons, Lindsay Hoyle, reprimands the chancellor, Rachel Reeves, in the Commons for giving information to journalists in the US about the upcoming Budget, in potential contravention of the ministerial code, which expects major government announcements to be made in the Commons before to the news media.
What we have got is the smoking gun - the thing that caused his illness and was given to him with malice." Subsequently, French and Russian teams claimed that the elevated 210Po levels were not the result of deliberate poisoning, and did not cause Arafat's death. It has also been suspected that Russian businessman Roman Tsepov was killed with polonium. He had symptoms similar to Litvinenko's.
In this case, the objective is the creation of chassis genomes based on necessary genes and other required DNA sequences rather than the design of metabolic or regulatory pathways based on abstract criteria.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is run alongside mass spectrometry. The chromatogram separates components and gives a purity figure, while the mass spectrum confirms that the measured molecular mass matches the expected sequence. Neither measurement on its own is treated as sufficient.
Long-term holding is usually at minus twenty degrees Celsius in a sealed, desiccated container. A refrigerator is adequate for short intervals before use. Light exposure is normally avoided as well. Allowing a cold container to warm before opening reduces moisture condensation on the contents.
Repeated cycles are generally avoided. Each freeze and thaw can promote aggregation or loss of peptide to container surfaces, which reduces the amount available for later work. Dividing a solution into single-use portions at the outset is the usual way to limit this problem.
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.