This is a working overview of Aspartimide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-04-29 and is reviewed periodically as new material appears.
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.
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.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
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.
| 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 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.
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 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.
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.
The two substrates of this enzyme are propylene glycol and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are L-lactaldehyde, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is propane-1,2-diol:NADP+ oxidoreductase. Other names in common use include lactaldehyde (reduced nicotinamide adenine dinucleotide phosphate), reductase, NADP+-1,2-propanediol dehydrogenase, propanediol dehydrogenase, 1,2-propanediol:NADP+ oxidoreductase, and lactaldehyde reductase (NADPH).
=== Metal recovery === A recent study highlights the first report of thermo-responsive rare-earth elements (REE)-selective protein. The ELP and the REE-binding domain are genetically fused to form REE-selective and thermo-responsive genetically encoded ELP called RELP for the selective extraction and recovery of total REEs. RELP shows a selective and repeatable biosorption platform for REE recovery. The authors highlighted that technology can be adapted to recover other precious metals and commodities.
A bulk material should have constant physical properties regardless of its size, but at the nano-scale this is often not the case. Size-dependent properties are observed such as quantum confinement in semiconductor particles, surface plasmon resonance in some metal particles, and superparamagnetism in magnetic materials. Nanoparticles exhibit a number of special properties relative to bulk material. For example, the bending of bulk copper (wire, ribbon, etc.) occurs with movement of copper atoms/clusters at about the 50 nm scale. Copper nanoparticles smaller than 50 nm are considered super hard materials that do not exhibit the same malleability and ductility as bulk copper. The change in properties is not always desirable. Ferroelectric materials smaller than 10 nm can switch their polarization direction using room temperature thermal energy, thus making them useless for memory storage. Suspensions of nanoparticles are possible because the interaction of the particle surface with the solvent is strong enough to overcome differences in density, which usually result in a material either sinking or floating in a liquid. Nanoparticles often have unexpected visual properties because they are small enough to confine their electrons and produce quantum effects. For example, gold nanoparticles appear deep red to black in solution. The often very high surface area to volume ratio of nanoparticles provides a tremendous driving force for diffusion, especially at elevated temperatures. Sintering is possible at lower temperatures and over shorter durations than for larger particles.
The collection grew slowly and suffered another major fire in 1851, which destroyed two-thirds of Jefferson's original books. The Library of Congress faced space shortages, understaffing, and lack of funding, until the American Civil War increased the importance of legislative research to meet the demands of a growing federal government. In 1870, the library gained the right to receive two copies of every copyrightable work printed in the United States; it also built its collections through acquisitions and donations. Between 1890 and 1897, a new library building, now the Thomas Jefferson Building, was constructed. Two additional buildings, the John Adams Building (opened in 1939) and the James Madison Memorial Building (opened in 1980), were later added. The LC's Congressional Research Service provides objective non-partisan research to Congress to assist it in passing legislation. The library is open to the public for research, although only members of Congress, their staff, and library employees may borrow materials for use outside the library.
The supply of PUFAs for ferroptosis also depends on glutaminolysis — the uptake of glutamine via membrane transporters SLC38A1 and SLC1A5, its conversion to α-ketoglutarate, and subsequent mitochondrial catabolism to generate acetyl-CoA for fatty acid synthesis. This process is regulated by AMP-activated protein kinase (AMPK), which plays a dual role in ferroptosis through phosphorylation of either Beclin-1 or acetyl-CoA carboxylase. Under stress conditions, lipid droplets can also release free fatty acids, further amplifying lipid peroxidation. Ferroptosis has been shown to involve distinct cellular organelles, which includes peroxisomes, mitochondria, the endoplasmic reticulum (ER) and lysosomes. It has been a debate in the scientific community as to where ferroptosis is initiated in the cell, and now research points to the lysosome, where the chemical environment (iron, pH an hydrogen peroxide) are favorable. Oxidation of phospholipids can occur when free radicals abstract electrons from a lipid molecule (typically affecting polyunsaturated fatty acids), thereby promoting their oxidation. The primary cellular mechanism of protection against ferroptosis is mediated by the selenoprotein GPX4, a glutathione-dependent hydroperoxidase that converts lipid hydroperoxides into non-toxic lipid alcohols. The abundant lipid soluble vitamin α-tocopherol complements GPX4 by acting as a radical-trapping antioxidant for lipid peroxyl radicals, the chief membrane damaging species in ferroptosis that cannot be reduced by GPX4.
Sources: en.wikipedia.org
Tralokinumab sold under the brand names Adtralza (EU/UK) and Adbry (US) among others, is a human monoclonal antibody used for the treatment of atopic dermatitis. Tralokinumab targets the cytokine interleukin 13. The most common side effects include upper respiratory tract infections (colds and other infections of the nose and throat), reactions at the injection site, and redness and discomfort in the eye. Tralokinumab was approved for medical use in the European Union and in the United Kingdom in June 2021. It was approved for medical use in the United States in December 2021. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.
The Germans also made use of CH for their own passive radar system, known as Klein Heidelberg. This used CH's transmissions as their source, and a series of antennas along the Channel coast as the receiver. By comparing the time of arrival of the signals from a selected aircraft, its range and direction could be determined with some accuracy. Since the system sent out no signals of its own, the allies were not aware of it until they overran the stations in 1944. Most of the stations had only just been built when they were overrun.
=== Osteoconduction === Osteoconduction is termed as "the property of a material to support tissue ingrowth, osteoprogenitor cell growth, and development for bone formation to occur". In the context of bone grafting it occurs when the bone graft material serves as a scaffold for new bone growth that is perpetuated by the native bone. Osteoblasts from the margin of the defect that is being grafted utilize the bone graft material as a framework upon which to spread and generate new bone. Osteoblasts do not originate from the donor tissue, but through the internal ingrowing of the host's cells. The proper bonding of bioactive chemicals (Beta-Tricalcium Phosphate) in implants used in bone grafting surgery allow the promotion of osteoconductivity in the area of a defect. In the very least, a bone graft material should be osteoconductive by being made up of these bioactive chemicals.
=== For diagnostics === The original goal for paper-based microfluidics (μPAD) was to make low-cost and user-friendly point-of-care (POC) devices that can be operated without the assistance of medical personnel or any other qualified specialist in resource-limited and rural areas. To achieve this goal, μPAD should fit the "Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, Deliver" criteria, provided by the World Health Organization (WHO), which are the requirements for diagnostic testing for resource-constrained settings. However, in POC's official "Guide to aid the selection of diagnostic tests", it is stated that these criteria are generic and can be modified according to test application. The main problem of paper-based microfluidic diagnostics is that research in this field is directed on providing new concepts and ideas rather than on improving user acceptance and as a result, most μPAD devices are still unable to be interpreted by non-professional users. However, POC is not the only application of paper-based microfluidics for diagnostics. Recently, a paper was employed in the production of more complicated microfluidic analytical devices, called lab-on-a-chip (LOC) devices, which are also used in diagnostics. Using paper to make LOC devices instead of polydimethylsiloxane (PDMS) and glass can decrease cost and size while increasing portability. This allows LOC devices to become more accessible in resource-limited conditions.
Sources: en.wikipedia.org
=== 116th Congress (2019–2021) === In March 2019, Kennedy introduced the Holding Foreign Companies Accountable Act, which Trump signed into law on December 18, 2020. The law prohibits any company from listing on an American stock exchange if it refuses to allow the Public Company Accounting Oversight Board to audit its annual private audit for three consecutive years. It also requires companies to disclose whether they are owned by a foreign government. In 2019, Kennedy again introduced a bill to extend the National Flood Insurance Program. It extended the program through June 14, 2019, rather than lapsing on May 31. The bill passed the Senate on May 23, 2019, and was signed into law.
== Further reading == Godwin, P.; Hancock, I. (1995). Rhodesians Never Die – The Impact of War and Political Change on White Rhodesia. Harare, Zimbabwe: Baobab Books. ISBN 0-908311-82-6. Stiff, P.; Reid-Daly, R. (1982). Selous Scouts: Top Secret War. Alberton, South Africa: Galago. Stapleton, T. (2011). African Police and Soldiers in Colonial Zimbabwe, 1923–80. University Rochester Press. ISBN 978-1580463805. Stapleton, Timothy J. (2011). African Police and Soldiers in Colonial Zimbabwe, 1923–80. Rochester, New York: University of Rochester Press. ISBN 9781580467339. Stapleton, Tim (2015). "'Tracking, tracking and more tracking was their motto': bush tracking and warfare in late twentieth-century Southern Africa". War & Society. 34 (4): 301–323. doi:10.1080/07292473.2015.1128658. S2CID 155302459. White, Luise (November 2004). "Precarious Conditions: A Note on Counter-Insurgency in Africa after 1945". Gender & History. 16 (3): 603–625. doi:10.1111/j.0953-5233.2004.00358.x. S2CID 143212408.
== Chestnut mimics == Bay horses also have reddish coats, but they have a black mane, tail, legs and other point coloration. The presence of true black points, even if obscured by white markings, means that a horse is not chestnut. Seal brown or dark bay horses are not chestnut but may be confused with a liver chestnut. Those unfamiliar with horse coat color terminology often call most horses "brown". including chestnuts. Brown, which may be difficult to distinguish visually from dark bay, is always accompanied by black points. Liver chestnuts, in particular, are mistakenly called brown or "seal brown". Silver bay horses typically have chocolate- to red-brown bodies with silvered mane, tail, and legs. The flat reddish-brown color and lack of easily identified black points can confuse even knowledgeable horse persons. Silver dapple horses usually hint at black or dark gray pigment at the roots of the mane and tail, and where their silver points end on the legs. Silvers look a bit "off"-chestnut. To further confuse matters, some flaxen chestnuts have silverish streaks in their manes and tails. However, genetic testing can clarify matters.
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 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.