lyophilised powder raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2025-09-10 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.
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.
| 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.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
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.
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.
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.
=== Aviation === In 2023, Transworld Group expanded into the aviation sector with its luxury private jet charter service, Airavat, operating in the Middle East, Europe, and Asia. In 2024, Transworld Group entered into a joint venture with former SpiceJet COO Arun Kashyap's Sirius India Airlines to begin operations in India.
== History == Vegetable soup dates to ancient history. A 5th-century Roman cookbook included a recipe for "a forerunner of onion soup." Broth is mentioned by approximately the year 1000 and potage by the 1400s. Clifford Wright has stated that cabbage soup was important in medieval Italian cuisine. In central Appalachia, vegetable soup, also referred to as winter vegetable soup and country soup, is a traditional staple food and common dish during the months of December–February among Appalachian highlanders.
==== MeSH D13.695.667 – purine nucleotides ==== MeSH D13.695.667.138 – adenine nucleotides MeSH D13.695.667.138.124 – adenosine diphosphate MeSH D13.695.667.138.124.070 – adenosine diphosphate sugars MeSH D13.695.667.138.124.070.075 – adenosine diphosphate glucose MeSH D13.695.667.138.124.070.125 – adenosine diphosphate ribose MeSH D13.695.667.138.124.070.125.040 – o-acetyl-adp-ribose MeSH D13.695.667.138.124.070.125.195 – cyclic adp-ribose MeSH D13.695.667.138.180 – adenosine monophosphate MeSH D13.695.667.138.180.080 – adenosine phosphosulfate MeSH D13.695.667.138.236 – adenosine triphosphate MeSH D13.695.667.138.236.050 – adenylyl imidodiphosphate MeSH D13.695.667.138.236.250 – ethenoadenosine triphosphate MeSH D13.695.667.138.382 – coenzyme a MeSH D13.695.667.138.382.300 – acyl coenzyme a MeSH D13.695.667.138.382.300.020 – acetyl coenzyme a MeSH D13.695.667.138.382.300.500 – malonyl coenzyme a MeSH D13.695.667.138.382.300.700 – palmitoyl coenzyme a MeSH D13.695.667.138.395 – cyclic amp MeSH D13.695.667.138.395.225 – 8-bromo cyclic adenosine monophosphate MeSH D13.695.667.138.395.250 – bucladesine MeSH D13.695.667.138.410 – deoxyadenine nucleotides MeSH D13.695.667.138.506 – flavin-adenine dinucleotide MeSH D13.695.667.138.694 – nad MeSH D13.695.667.138.749 – nadp MeSH D13.695.667.138.850 – phosphoadenosine phosphosulfate MeSH D13.695.667.138.925 – vidarabine phosphate MeSH D13.695.667.454 – guanine nucleotides MeSH D13.695.667.454.160 – cyclic gmp MeSH D13.695.667.454.160.325 – dibutyryl cyclic gmp MeSH D13.695.667.454.200 – deoxyguanine nucleotides MeSH D13.695.667.454.340 – guanosine diphosphate MeSH D13.695.667.454.340.350 – guanosine diphosphate sugars MeSH D13.695.667.454.340.350.400 – guanosine diphosphate fucose MeSH D13.695.667.454.340.350.500 – guanosine diphosphate mannose MeSH D13.695.667.454.440 – guanosine pentaphosphate MeSH D13.695.667.454.480 – guanosine tetraphosphate MeSH D13.695.667.454.504 – guanosine triphosphate MeSH D13.695.667.454.504.380 – guanosine 5'-o-(3-thiotriphosphate) MeSH D13.695.667.454.504.400 – guanylyl imidodiphosphate MeSH D13.695.667.454.525 – 5'-guanylic acid MeSH D13.695.667.454.700 – rna caps MeSH D13.695.667.454.700.710 – rna cap analogs MeSH D13.695.667.616 – inosine nucleotides MeSH D13.695.667.616.300 – cyclic imp MeSH D13.695.667.616.400 – inosine diphosphate MeSH D13.695.667.616.500 – inosine monophosphate MeSH D13.695.667.616.800 – inosine triphosphate
The city has hosted numerous major sporting events, including the inaugural AFC Asian Cup, the 2008 Summer Olympics equestrian events, the 2009 East Asian Games, the Rugby World Cup Sevens in 1997 and 2005, the 2005 World Squash Championships and 2025 World Grand Prix (snooker). The territory regularly hosts the Hong Kong Sevens, Hong Kong Marathon, Hong Kong Open (tennis), Hong Kong Tennis Classic and LIV Golf Hong Kong. Hong Kong represents itself separately from mainland China, with its own sports teams in international competitions. The territory has participated in almost every Summer Olympics since 1952 (with the exception of its support of the 1980 Summer Olympics boycott) and has earned nine medals. Lee Lai-shan won the territory's first Olympic gold medal at the 1996 Atlanta Olympics, and Cheung Ka Long won the second one in Tokyo 2020. Hong Kong athletes have won 126 medals at the Paralympic Games and 17 at the Commonwealth Games. Although they are no longer part of the Commonwealth of Nations, the city's last appearance was in 1994.
Nondeletion forms: These defects, in general, involve a single base-pair substitution or small insertions near or upstream of the HBB gene. Deletion forms: base-pair deletions of different sizes involving the HBB gene produce syndromes such as hereditary persistence of fetal hemoglobin syndrome. Mutations are characterized as (βo) if they prevent any formation of β globin chains, and mutations are characterized as (β+) if they allow some β globin chain formation to occur.
Sources: en.wikipedia.org
== Discovery == NAPE-PLD is an enzyme activity - a phospholipase, acting on phospholipids found in the cell membrane. It is not homology but the chemical outcome of its activity that classes it as phospholipase D. The enzymatic activity was discovered and characterized in a series of experiments culminating in the 2004 publication of a biochemical purification scheme from which peptide sequencing could be accomplished. Researchers homogenized (finely ground) hearts from 150 rats and subjected the resulting crude lysate to sucrose sedimentation at 105,000 x g to separate the cell membranes from the remainder of the cell. The integral membrane proteins were then solubilized using octyl glucoside and subjected to four column chromatography steps (HiTrap SP HP cation-exchange column, HiTrap Q anion-exchange column, HiTrap Blue affinity column, Bio-Gel HTP hydroxyapatite column). Each of these separates the different types of membrane proteins into different sample containers when the proteins are eluted from the column over time, and by measuring the activity of samples in each container it was possible to track which ones received the active enzyme. Measurement of the enzyme activity was done by thin layer chromatography of a radioactive substrate sensitive to the NAPE-PLD enzymatic activity: Cleavage of the substrate affected where it appeared on the plate when the radiation was detected on a bioimaging analyzer.
Knoxville's pre-1850s population consisted primarily of European-American (of mostly English, Scots-Irish, or German descent) Protestants and a small community of free blacks and slaves. Railroad construction in the 1850s brought to the city large numbers of Irish Catholic immigrants, who helped establish the city's first Catholic congregation in 1855. The Swiss were another important group in 19th-century Knoxville, with businessmen James G. Sterchi and Peter Staub, Supreme Court justice Edward Terry Sanford, philosopher Albert Chavannes, and builder David Getaz, all claiming descent from the city's Swiss immigrants. Welsh immigrants brought mining and metallurgical expertise to the city in the late 1860s and 1870s. After the Civil War, African Americans, both freed slaves and blacks that had been free prior to the war, played an increasing role in the city's political and economic affairs. Racetrack and saloon owner Cal Johnson, born a slave, was one of the wealthiest African Americans in the state by the time of his death. Attorney William F. Yardley, a member of the city's free black community, was Tennessee's first black gubernatorial candidate in 1876. Knoxville College was founded in 1875 to provide educational opportunities for the city's black community. Greek immigrants began arriving in Knoxville in significant numbers in the early 20th century.
Association for Molecular Pathology v. Myriad Genetics, Inc. AMP was the lead plaintiff in a landmark lawsuit challenging gene patents. As described by Executive Director Mary Williams, “gene patents created an intractable challenge for medical professionals and presented a potential barrier to entry for new technologies. In order for the field to advance, the courts needed to weigh in.” In June 2013, the U.S. Supreme Court unanimously ruled, “A naturally occurring DNA segment is a product of nature and not patent eligible merely because it has been isolated, but cDNA is patent eligible because it is not naturally occurring.” On the fifth anniversary of the ruling, AMP released a video providing some of the background about AMP's decision to join the case and its journey to the Supreme Court.
== History == Trimipramine was developed by Rhône-Poulenc. It was patented in 1959 and first appeared in the literature in 1961. The drug was first introduced for medical use in 1966, in Europe. It was not introduced in the United States until later in 1979 or 1980.
Sources: en.wikipedia.org
=== Stability of naturally occurring nuclides === Most naturally occurring nuclides on earth are beta stable. Nuclides that are not beta stable have half-lives ranging from under a second to periods of time significantly greater than the age of the universe. One common example of a long-lived isotope is the odd-proton odd-neutron nuclide 4019K, which undergoes all three types of beta decay (β−, β+ and electron capture) with a half-life of 1.248×109 years.
In May 2021, Freddy's hired Chris Dull as CEO to take over the top post from co-founder Randy Simon. In August 2022, Freddy's hired Brian Wise as COO to take over the operations post from co-founder Scott Redler. In November 2022, the company signed a master franchise and development agreement that will allow the brand to expand into Canada by 2025, opening restaurants in nine provinces. In August 2025, Rhône Group agreed to acquire Freddy's from Thompson Street Capital Partners, who acquired the brand in 2021, for an enterprise value of around $700 million. The acquisition was finalized in September 2025.
The World's Water Data Page FAO Comprehensive Water Database, AQUASTAT The Water Conflict Chronology: Water Conflict Database Archived 16 January 2013 at the Wayback Machine Water science school (USGS) Portal to The World Bank's strategy, work and associated publications on water resources America Water Resources Association Archived 24 March 2018 at the Wayback Machine Water on the web Water structure and science Archived 28 December 2014 at the Wayback Machine "Why water is one of the weirdest things in the universe", Ideas, BBC, Video, 3:16 minutes, 2019 The chemistry of water Archived 19 June 2020 at the Wayback Machine (NSF special report) The International Association for the Properties of Water and Steam Archived 27 September 2022 at the Wayback Machine H2O: The Molecule That Made Us, a 2020 PBS documentary
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.
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.