If you have been reading about tetrapeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-10-20. Numbers and descriptions here follow the published literature rather than marketing material.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
（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.
Chemically, the molecule consists of four amino acid residues joined by three peptide bonds, with a free N-terminal amino group and a free C-terminal carboxyl group. Its molecular formula is C14H22N4O9, and its monoisotopic mass is approximately 390 daltons. The acidic glutamate and aspartate side chains give the peptide a net negative charge near neutral pH, a property that shapes its chromatographic behaviour and solubility profile. No disulfide bridges or other post-translational modifications are present, so the primary sequence alone defines the structure.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Computed for the free acid of Ala-Glu-Asp-Gly |
| Molecular mass | About 390.35 g/mol | Free peptide; salt forms shift the value |
| Appearance | White to off-white solid | Typical of short peptides after freeze-drying |
| Solubility class | Freely soluble in water | Aqueous buffers are also commonly used |
| Common synonyms | Epitalon, epithalone, AEDG | AEDG is the single-letter sequence |
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 most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
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.
==== Districts ==== Each Police District is either coterminous with the Revenue district or in the case of Government Railway Police districts, is located within a number of revenue districts. It is headed by a District Superintendent of Police (or simply called Superintendent of Police). Each district comprises two or more Sub-Divisions, several Circles and Police Stations. But in recent times, several districts are divided into police districts for better police administration. Each of those police districts are headed by an SP.
In September 2014, Creative Business House along with Donnons Leur Une Chance, created the International Dwarf Fashion Show to raise awareness and boost self-confidence of people living with dwarfism. A number of reality television series on Lifetime, beginning with Little Women: LA in 2014, focused on showing the lives of women living with dwarfism in various cities around the United States.
The use of pulses of different durations, frequencies, or shapes in specifically designed patterns or pulse sequences allows production of a spectrum that contains many different types of information about the molecules in the sample. In multi-dimensional nuclear magnetic resonance spectroscopy, there are at least two pulses: one leads to the directly detected signal and the others affect the starting magnetization and spin state prior to it. The full analysis involves repeating the sequence with the pulse timings systematically varied in order to probe the oscillations of the spin system are point by point in the time domain. Multidimensional Fourier transformation of the multidimensional time signal yields the multidimensional spectrum. In two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR), there will be one systematically varied time period in the sequence of pulses, which will modulate the intensity or phase of the detected signals. In 3D-NMR, two time periods will be varied independently, and in 4D-NMR, three will be varied. There are many such experiments. In some, fixed time intervals allow (among other things) magnetization transfer between nuclei and, therefore, the detection of the kinds of nuclear–nuclear interactions that allowed for the magnetization transfer. Interactions that can be detected are usually classified into two kinds. There are through-bond and through-space interactions.
=== Testing === The American Heart Association recommends testing cholesterol every four to six years for people aged 20 years or older. A separate set of American Heart Association guidelines issued in 2013 indicates that people taking statin medications should have their cholesterol tested 4–12 weeks after their first dose and then every 3–12 months thereafter. For men ages 45 to 65 and women ages 55 to 65, a cholesterol test should be performed every one to two years, and an annual test should be performed for seniors over the age of 65. After 12 hours of fasting, a blood sample is taken by a healthcare professional from an arm vein to measure a lipid profile for a) total cholesterol, b) HDL cholesterol, c) LDL cholesterol, and d) triglycerides. Results may be expressed as "calculated", indicating a calculation of total cholesterol, HDL, and triglycerides. Cholesterol is tested to determine for "normal" or "desirable" levels if a person has a total cholesterol of 5.2 mmol/L or less (200 mg/dL), an HDL value of more than 1 mmol/L (40 mg/dL, "the higher, the better"), an LDL value of less than 2.6 mmol/L (100 mg/dL), and a triglycerides level of less than 1.7 mmol/L (150 mg/dL). Blood cholesterol in people with lifestyle, aging, or cardiovascular risk factors, such as diabetes mellitus, hypertension, family history of coronary artery disease, or angina, are evaluated at different levels.
Sources: en.wikipedia.org
Tang L, Wu JJ, Ma Q, et al. (July 2010). "Human lactoferrin stimulates skin keratinocyte function and wound re-epithelialization". The British Journal of Dermatology. 163 (1): 38–47. doi:10.1111/j.1365-2133.2010.09748.x. PMID 20222924. S2CID 2387064.
According to Ahmad Dallal, Abū Rayhān al-Bīrūnī states that "there is no observable evidence that rules out the possibility of vacuum". The suction pump was described by Arab engineer Al-Jazari in the 13th century, and later appeared in Europe from the 15th century. European scholars such as Roger Bacon, Blasius of Parma and Walter Burley in the 13th and 14th century focused considerable attention on issues concerning the concept of a vacuum. The commonly held view that nature abhorred a vacuum was called horror vacui. There was even speculation that even God could not create a vacuum if he wanted and the 1277 Paris condemnations of Bishop Étienne Tempier, which required there to be no restrictions on the powers of God, led to the conclusion that God could create a vacuum if he so wished. From the 14th century onward increasingly departed from the Aristotelian perspective, scholars widely acknowledged that a supernatural void exists beyond the confines of the cosmos itself by the 17th century. This idea, influenced by Stoic physics, helped to segregate natural and theological concerns. Almost two thousand years after Plato, René Descartes also proposed a geometrically based alternative theory of atomism, without the problematic nothing–everything dichotomy of void and atom.
=== August === 1 August Nationwide reports that house prices fell by 3.8% in July, the sharpest decline since July 2009. The UK's first permanent drone delivery service begins, with Royal Mail and Skyports establishing a daily inter-island mail distribution between three islands on Orkney. Changes on excise duty for alcohol come into force, with the tax levied depending on a drink's strength. Former SNP MP Margaret Ferrier loses her seat, following a successful recall petition, triggering a by-election. 2 August – COVID-19 in the UK: The UK Health Security Agency reports the spread of a new variant known as EG.5.1. 3 August The National Risk Register publishes its latest report on future threats facing the UK. It puts the chance of another pandemic at between 5% and 25%. Other risks include extreme weather caused by worsening climate change, advances in artificial intelligence (AI) systems, terrorism such as cyberattacks on infrastructure, and the assassination of public figures. Greenpeace activists climb onto the roof of Rishi Sunak's North Yorkshire home, unfurling sheets of black fabric, in protest at his recent decision to expand oil and gas production in the North Sea. The Bank of England raises its baseline interest rate from 5% to 5.25%, the 14th consecutive increase and the highest level since April 2008. The Bank also predicts inflation to fall below 5% in the final quarter of 2023. Brexit: Checks on fresh food from the EU are delayed for a fifth time, amid concerns over red tape.
=== High-throughput proteomic technologies === Proteomics has steadily gained momentum over the past decade with the evolution of several approaches. Few of these are new, and others build on traditional methods. Mass spectrometry-based methods, affinity proteomics, and micro arrays are the most common technologies for large-scale study of proteins.
=== First radiation protection regulations === A leaflet published by the German Radiological Society (DRG) in 1913 was the first systematic approach to radiation protection. The physicist and co-founder of the society, Bernhard Walter (1861-1950), was one of the pioneers of radiation protection. The International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU) were established at the Second International Congress of Radiology in Stockholm in 1928. In the same year, the first international radiation protection recommendations were adopted and each country represented was asked to develop a coordinated radiation control program. The United States representative, Lauriston Taylor of the US Bureau of Standards (NSB), formed the Advisory Committee on X-Ray and Radium Protection, later renamed the National Committee on Radiation Protection and Measurements (NCRP). The NCRP received a Congressional charter in 1964 and continues to develop guidelines to protect individuals and the public from excessive radiation. In the years that followed, numerous other organizations were established by almost every president.
Sources: en.wikipedia.org
== Metabolite Quantification and Analysis == In order to identify and quantify metabolites produced by the body, various detection methods have been employed. Most often, these involve the use of nuclear magnetic resonance (NMR) spectroscopy or mass spectrometry (MS), providing universal detection, identification and quantification of metabolites in individual patient samples. Although both processes are used in pharmacometabolomic analyses, there are advantages and disadvantages for using either nuclear magnetic resonance (NMR) spectroscopy- or mass spectrometry (MS)-based platforms in this application.
In a December 2022 editorial published just before being elected US House speaker, Kevin McCarthy wrote that "China and the US are locked in a cold war". The op-ed also announced the creation of the United States House Select Committee on Strategic Competition between the United States and the Chinese Communist Party. In early 2023, Jorge Heine, former Chilean ambassador to China and professor of international relations at Boston University, said the looming new Cold War between the US and China has become apparent to "a growing consensus", and described the new Cold War as "more alike than [it is] different" from the one fought between the US and Soviet Union, and saying the presence of "ideological-military overtones is now widely accepted". After the 2023 Chinese balloon incident, Evan Osnos wrote for The New Yorker "The blocs in this new cold war are hardening." Shortly after the Russian invasion of Ukraine, Germany had "announced a 'turning point'" in its relationship with Russia. The 2022 Madrid NATO summit hosted leaders from South Korea, Australia, Japan, and New Zealand, who all "voiced unprecedented concern about China's ambitions". The Biden administration strengthened the U.S.'s military ties and activities with Australia, Japan, India, and the Philippines, to "bolster its ability to defend Taiwan". In the October 2024 article for the TomDispatch blog, a history professor Alfred W. McCoy wrote that, despite rising renewed tensions between China and the US, the Asia-Pacific allies of the US would be likely losers.
The second step in the formation of SCOBY is the introduction of different bacteria into the liquid culture to convert the ethanol product of fermentation into organic acids such as acetic acid, which is a type of ethanol metabolism (lactic acid bacteria may also be added, producing lactic acid from lactic acid fermentation on sugars). A possible byproduct of this reaction is cellulose, which serves as the foundation for the SCOBY biofilm. Like yeasts, the species of bacteria chosen as well as culture conditions directly affect both the characteristics of the liquid kombucha product as well as the composition and morphology of the SCOBY pellicle. While there are many species that have the mechanisms necessary to form cellulose such as Acetobacter and Komagataeibacter, Gluconaceobacter are one of the most populous used, residing in 86–99% of both liquid and biofilm cultures. The necessary culturing conditions of these bacteria are similar to that of yeasts, but require more oxygen due to their aerobic nature in oxidizing ethanol to form organic acids. Once the internal conditions of the co-culture are in place, the symbiotic mixture is left to ferment. Certain studies have claimed optimal fermentation time to be 10 days, but the duration can be modified to change the contents of the yield; greater fermentation times correlate with higher levels of organic acids and other amino acids, which can attribute to the sour undertones of some Kombucha.
==== MeSH D13.570.685 – pyrimidine nucleosides ==== MeSH D13.570.685.245 – cytidine MeSH D13.570.685.245.217 – azacitidine MeSH D13.570.685.245.453 – cytarabine MeSH D13.570.685.245.453.050 – ancitabine MeSH D13.570.685.245.500 – deoxycytidine MeSH D13.570.685.245.500.250 – bromodeoxycytidine MeSH D13.570.685.245.500.950 – zalcitabine MeSH D13.570.685.245.500.950.500 – lamivudine MeSH D13.570.685.350 – formycins MeSH D13.570.685.350.200 – coformycin MeSH D13.570.685.350.200.700 – pentostatin MeSH D13.570.685.705 – thymidine MeSH D13.570.685.705.875 – stavudine MeSH D13.570.685.705.900 – trifluridine MeSH D13.570.685.705.950 – zidovudine MeSH D13.570.685.725 – tunicamycin MeSH D13.570.685.852 – uridine MeSH D13.570.685.852.150 – arabinofuranosyluracil MeSH D13.570.685.852.176 – azauridine MeSH D13.570.685.852.250 – 3-deazauridine MeSH D13.570.685.852.300 – deoxyuridine MeSH D13.570.685.852.300.150 – bromodeoxyuridine MeSH D13.570.685.852.300.350 – floxuridine MeSH D13.570.685.852.300.400 – idoxuridine MeSH D13.570.685.852.628 – pseudouridine MeSH D13.570.685.852.800 – tetrahydrouridine MeSH D13.570.685.852.829 – thiouridine
Sources: en.wikipedia.org
It is a four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine. The chain is unmodified and contains only standard proteinogenic residues, which makes it straightforward to produce by solid-phase synthesis and to characterise by standard peptide methods.
Epitalon and epithalon both circulate, and the difference reflects transliteration of a name coined in Russian-language publications. Reference to the extract it derives from, epithalamin, explains the shared stem. Databases and suppliers are inconsistent, so a search for one spelling alone may miss relevant entries.
No. Epithalamin is a multi-component preparation obtained from pineal tissue, and its exact composition is not fully characterised. Epitalon is a single defined tetrapeptide described as a short synthetic counterpart of that extract, so the two are related in origin but not interchangeable in identity.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.