RP-HPLC 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 2025-08-23 and is reviewed periodically as new material appears.
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.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
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.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
Epitalon is a synthetic tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
Ronald Charles Beavis (better known professionally as Ron Beavis) is a Canadian protein biochemist, who has been involved in the application of mass spectrometry to protein primary structure, with applications in the fields of proteomics and analytical biochemistry. He has developed methods for measuring the identity and post-translational modification state of proteins obtained from biological samples using mass spectrometry. He is currently best known for developing new methods for analyzing proteomics data and applying the results of these methods to problems in computational biology.
Carbon dioxide can be used to extinguish flames by flooding the environment around the flame with the gas. It does not itself react to extinguish the flame, but starves the flame of oxygen by displacing it. Some fire extinguishers, especially those designed for electrical fires, contain liquid carbon dioxide under pressure. Carbon dioxide extinguishers work well on small flammable liquid and electrical fires, but not on ordinary combustible fires, because they do not cool the burning substances significantly, and when the carbon dioxide disperses, they can catch fire upon exposure to atmospheric oxygen. They are mainly used in server rooms. Carbon dioxide has also been widely used as an extinguishing agent in fixed fire-protection systems for local application of specific hazards and total flooding of a protected space. International Maritime Organization standards recognize carbon dioxide systems for fire protection of ship holds and engine rooms. Carbon dioxide-based fire-protection systems have been linked to several deaths, because it can cause suffocation in sufficiently high concentrations. A review of CO2 systems identified 51 incidents between 1975 and the date of the report (2000), causing 72 deaths and 145 injuries.
Any law(s) and regulation(s) addressing the conduct of clinical trials of investigational products of the jurisdiction where trial is conducted. (ICH E6) Approval (in relation to institutional review boards (IRBs))
It was announced in March 2017 that Galloway was standing as an independent candidate at the Manchester Gorton by-election, following the death of Sir Gerald Kaufman. Gorton had been one of Labour's safest seats. The by-election was cancelled following the announcement of the 2017 snap general election being held on 8 June. Galloway transferred his candidacy to the general election. Labour easily retained the seat; Galloway came a distant third with 6% of the vote. In the 2019 general election, Galloway contested the Parliamentary seat of West Bromwich East as an independent, describing himself as supportive of Corbyn's leadership and Brexit. He came sixth with 489 votes. On 14 December 2019, Galloway launched the Workers Party of Britain, which describes itself as "economically radical with an independent foreign policy" and "unequivocally committed to class politics". Galloway is the party's leader. In 2020 Galloway announced his intention to stand in an expected by-election in Rutherglen and Hamilton West, after sitting MP Margaret Ferrier breached COVID regulations, but the by-election was not held for 3 years. Galloway led All for Unity in the 2021 Scottish Parliament election and announced his intention to vote for the Conservative Party on the constituency vote, and for his party on the list vote. This contradicted other occasions when he said voting Conservative was something he would never consider. All for Unity received 23,299 votes in the election, or 0.9%, placing the party 7th nationally, with no seats.
Low-end restaurants and street vendors are the biggest end users of gutter oil, as they operate with lower profit margins than bigger restaurants. Oil is a large kitchen supply cost for some restaurants, so obtaining cheaper oil can allow a marginal restaurant to reduce its overall expenses. Chinese food is generally heavily dependent on oil due to most foods being fried, so cheaper meal prices for many price-sensitive consumers are possible if gutter oil is used instead of virgin oil. The situation becomes more serious because it is hard to distinguish reprocessed gutter oil from legitimate oil. Bleach is used to transform gutter oil's dark color into a more natural-looking one, and alkali additives are used to neutralize the abnormal pH caused by high concentrations of animal fats. Used kitchen oil can be purchased for between US$859 and US$937 per ton, while the cleaned and refined product can sell for US$1,560 per ton. Thus there is great economic incentive to produce and sell gutter oil.
Sources: en.wikipedia.org
acetylation The covalent attachment of an acetyl group (–COCH3) to a chemical compound, protein, or other biomolecule via an esterification reaction with acetic acid, either spontaneously or by enzymatic catalysis. Acetylation plays important roles in several metabolic pathways and in histone modification. Contrast deacetylation.
== Solute carrier family examples == (1) high affinity glutamate and neutral amino acid transporter (3) Heavy subunits of heteromeric amino acid transporters (6) Bacterial Leucine Transporter (LeuT) (7) cationic amino acid transporter/glycoprotein-associated (15) proton oligopeptide cotransporter (17) vesicular glutamate transporter (18) vesicular amine transporter (25) some mitochondrial carriers (26) multifunctional anion exchanger (32) vesicular inhibitory amino acid transporter (36) proton-coupled amino acid transporter (38) System A & N, sodium-coupled neutral amino acid transporter
Heseltine also favoured European cooperation in defence procurement, feeling that this allowed Europe to compete with US firms which receive huge orders from The Pentagon. Crick argues that his experience of Concorde in the early 1970s should have warned him that such multinational ventures are problematic and, because of the political capital invested, hard to cancel when things go wrong. Heseltine played an important role in persuading West German defence minister Manfred Wörner to back the joint Anglo-German-Spanish-Italian Eurofighter, and contrary to the wishes of Thatcher (and previous defence secretary John Nott) who preferred an American or British fighter. Cabinet refused to allow a loosening of the specifications to allow French company Dassault to become involved in the consortium. Agreement was reached at Turin in August 1985. Heseltine also sold 132 Tornados for £4bn to Saudi Arabia later in 1985, accepting oil instead of cash (to the displeasure of Peter Walker, Energy Secretary) so that they would buy British rather than US aircraft. This later formed part of the controversial Al-Yamamah arms deal, the main part of which was signed in 1988.
== Further reading == Singerman, Ariel; Useche, Pilar (26 February 2019). "FE983/FE983: Impact of Citrus Greening on Citrus Operations in Florida". University of Florida Institute of Food and Agricultural Sciences Electronic Data Information Source. Retrieved 16 February 2021. Zheng, Desen; Armstrong, Cheryl M; Yao, Wei; Wu, Bo; Luo, Weiqi; Powell, Charles; Hunter, Wayne; Luo, Feng; Gabriel, Dean; Duan, Yongping (10 January 2024). "Towards the completion of Koch's postulates for the citrus huanglongbing bacterium, Candidatus Liberibacter asiaticus". Horticulture Research. 11 (3). Oxford University Press. doi:10.1093/hr/uhae011. PMC 11783299. Hunter, W.B., Sinisterra-Hunter, X. 2018. Emerging RNA Suppression Technologies to Protect Citrus Trees from Citrus Greening Disease Bacteria. Advances in Insect Physiology 55:163-199. https://doi.org/10.1016/bs.aiip.2018.08.001 Sandoval-Mojica, A.F.; Altman, S.; Hunter, W.B.; Pelz-Stelinski, K.S. 2020. Peptide conjugated morpholino's for management of the Huanglongbing pathosystem. Pest Manag. Sci. doi: 10.1002/ps.5877. https://doi:101002/ps.5877 Sandoval-Mojica, A.G.; Hunter, W.B.; Aishwarya, V.; Bonilla, S.; Pelz-Stelinski, K.S. Antibacterial FANA oligonucleotides as a novel approach for managing the Huanglongbing pathosystem. Sci. Rep. 11:2760. (2021). doi:10.1038/s41598-021-82425-8 Hunter, W.B.; Cooper, W.R.; Sandoval-Mojica, A.F.; McCollum, G.; Aishwarya, V.; Pelz-Stelinski, K.S. (2021).
Sources: en.wikipedia.org
==== Potential path: sludge to food ==== PFOA and PFOS were detected in "very high" (low parts per million) levels in agricultural fields for grazing beef cattle and crops around Decatur, Alabama. The approximately 5000 acres of land were fertilized with "treated municipal sewage sludge, or biosolids". PFOA was also detected in fodder grass grown in these soils and the blood of the cattle feeding on this grass. The water treatment plant received process wastewater from a nearby perfluorochemical manufacturing plant. 3M says they managed their own wastes, but Daikin America "discharged process wastewater to the municipal waste treatment plant". If traced to meat, it would be the first time perfluorochemicals were traced from sludge to food. However, the USDA reported—with a detection limits of 20 parts per billion—non-detectable levels for both PFOA and PFOS in cattle muscle tissue.
=== Sequence entropy === In bioinformatics, a sequence entropy, also known as sequence complexity or information profile, is a numerical sequence providing a quantitative measure of the local complexity of a DNA sequence, independently of the direction of processing. The manipulations of the information profiles enable the analysis of the sequences using alignment-free techniques, such as for example in motif and rearrangements detection.
Psychedelic drug use can cause hallucinogen-induced psychotic disorder (HIPD). HIPD is a form of substance-induced psychosis. The symptoms of HIPD are psychosis with paranoia, delusions, hallucinations, disorganized thinking, disorganized behavior, or insomnia that continue after the effects of the drug. Individuals with a personal or family history of mental illness are at the highest risk for hallucinogen-induced psychotic disorder. HIPD due to psychedelics is most commonly associated with LSD, but can be caused by DMT, mescaline, and psilocybin as well. Hallucinogen-induced psychotic disorder is a medical emergency. Without treatment, the psychosis can persist for weeks or months. An atypical antipsychotic medication such as aripiprazole, quetiapine, olanzapine, or risperidone is used to treat HIPD. Psilocybin-induced states of mind share features with states experienced in psychosis and researchers have called for investigation of the relationship. Hallucinogen-induced psychotic disorder has been reported with psychedelics in small percentages of individuals, and the rates appear to be higher in people with schizophrenia. The rate of hallucinogen-induced psychotic disorder is 0.6% in randomized controlled trials that exclude individuals with bipolar disorder or schizophrenia. In studies that included individuals with schizophrenia, 3.8% developed hallucinogen-induced psychotic disorder.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
Vladimir Khavinson and colleagues at research institutes in Saint Petersburg developed and studied the peptide. Their program examined short peptides as regulators of aging and neuroendocrine function. Epitalon was one of several compounds produced by that group.