This is a working overview of tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-17. Anything still debated is marked as such rather than presented as settled.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
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.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
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.
| 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 |
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
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 peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
Leon Aarons is an Australian chemist who researches and teaches in the areas of pharmacodynamics and pharmacokinetics. He lives in the United Kingdom and from 1976 has been a professor of pharmacometrics at the University of Manchester. In the interest of promoting the effective development of drugs, the main focus of his work is optimizing pharmacological models, the design of clinical studies, and data analysis and interpretation in the field of population pharmacokinetics. From 1985 to 2010 Aarons was an editor emeritus of the Journal of Pharmacokinetics and Pharmacodynamics and is a former executive editor of the British Journal of Clinical Pharmacology.
The equilibrium constant for this dissociation reaction is known as a dissociation constant. The liberated proton combines with a water molecule to give a hydronium (or oxonium) ion H3O+ (naked protons do not exist in solution), and so Arrhenius later proposed that the dissociation should be written as an acid–base reaction:
The previous life: the first two nidanas, namely ignorance and mental fabrications. They are basis for the events in the present. Nyanatiloka, writing from a traditional Theravada perspective, calls these "karma process" (kamma-bhava). The present life: The third to the tenth nidanas (consciousness, nama-rupa, the sense bases, contact, feeling, craving, clinging, becoming) relate to the present life. This begins with the descent of vijnana (consciousness, perception) into the womb. Nyanatiloka notes that nidanas 3-7 are part of the "rebirth process" (uppatti-bhava) and nidanas are 8-10 are "karma process". The future life: The last two nidanas (birth, old age and death) represent the future lives conditioned by the present causes. Nyanatiloka states these last two nidanas are a "rebirth process". Bhikkhu Bodhi notes that this distribution of the 12 nidanas into three lives "is an expository device employed for the purpose of exhibiting the inner dynamics of the round. It should not be read as implying hard and fast divisions, for in lived experience the factors are always intertwined." Furthermore, Bodhi argues that these twelve causes are not something hidden, but are "the fundamental pattern of experience" which "always present, always potentially accessible to our awareness." Nagarjuna's Pratityasamutpada-hrdaya-karika also outlines the 12 nidanas as a rebirth process.
ImmTACs exert their activity through T cell redirection, a mechanism of action used by several other bi-specific biologics such as the Bi-specific T-cell engagers (BiTEs). After administration of the drug the picomolar affinity TCR portion of the ImmTAC binds to the cancerous or virally infected cell through specific recognition of target HLA-peptide complexes on their cell surface. This picomolar affinity binding results in the diseased cells becoming coated in CD3 co-receptor specific scFv antibody fragments that constitute the ImmTAC effector function. Any Cytotoxic T cell that subsequently comes into direct physical contact with the ImmTAC coated diseased cell is redirected to kill it, regardless of the specificity of its native TCR. This redirected killing does not require binding of any co-stimulatory molecules and is effected through the targeted release of perforin and granzyme from the redirected T cell that induces the targeted disease cell to die through an apoptosis mediated mechanism. However, the danger of activating a wide variety of nonspecific cytotoxic T cell clones via anti-CD3 scFv exists, leading to their proliferation and widespread autoimmunity.
The gold in the county council's coat of arms symbolises the wealth of the area. Black is for both mining and the Black Mountains. The fountain is a medieval heraldic charge displayed as a roundel barry wavy argent and azure. It represents water and refers to both the water catchment area and the rivers and lakes. Thus, the arms contain references to the hills and mountains, rivers and lakes, water supply and industry. The crest continues the colouring of the arms. A tower has been used in preference to a mural crown, which alludes to the county's military history and remains. From the tower rises a red kite, a bird almost extinct elsewhere in Britain but thriving in Powys. The bird is a "semé of black lozenges" for the former coal mining industry, while the golden fleece it carries is a reference to the importance of sheep rearing in the county. The county motto is: Powys – the paradise of Wales (Welsh: Powys Paradwys Cymru).
Sources: en.wikipedia.org
Major football clubs in West Yorkshire include Leeds United, Huddersfield Town, and Bradford City. Rugby league is also big in West Yorkshire. The teams who are, or have been, in the Super League are Bradford Bulls, Castleford Tigers, Halifax Panthers, Huddersfield Giants, Leeds Rhinos, and Wakefield Trinity. Other rugby league clubs in West Yorkshire include Batley Bulldogs, Dewsbury Rams, Featherstone Rovers, Hunslet Hawks and Keighley Cougars. Any combination of these teams playing against each other would be called a West Yorkshire derby even if the rivalry is not as great as other rivalries between teams in the area. The main rugby union club in the county is Yorkshire Carnegie. Elland Road is the largest stadium in the area, hosting Leeds United. The Headingley Stadium, a stadium complex also in Leeds, consists of a cricket and a rugby ground. The cricket ground is home of the Yorkshire County Cricket Club and the rugby ground is home to Leeds Rhinos. In Huddersfield, the John Smith's Stadium is home to Huddersfield Town and Huddersfield Giants. In Bradford, Valley Parade is the home of Bradford City, whereas the Odsal Stadium is the home of the Bradford Bulls. Other stadiums include Wheldon Road (Castleford), The Shay (Halifax), Belle Vue (Wakefield), Mount Pleasant (Batley), Crown Flatt (Dewsbury), Post Office Road (Featherstone), John Charles Centre for Sport (Hunslet) and Cougar Park (Keighley). There are two racecourses in West Yorkshire: Pontefract and Wetherby.
Although some biogeochemists such as Rogers et al. (2012) have identified sites of hydrothermal vents, the locations of known hydrothermal vent formations in deep sea systems is not well understood. The ocean floor is not well explored, with less than 1% being well known. Most of the hydrothermal vents scientists are currently aware of form along mid ocean ridges. The location of these systems is important to understanding their formation, as most accepted theories revolve around seismic activity, particularly near volcanic regions. Seismic activity during Paleocene and Eocene continental rifting led to an eruption of gases, liquids, and sediments from the Earth's core. This intrusive event created large craters sitting on top of sills. Sills are layers of igneous rock where magma intrudes between existing layers of stratified rock. These large craters on the seafloor are collections of hydrothermal vents. Distinct features of these vents include inward-dipped sedimentary strata, and sandstone dykes, pipes, and breccias. These features are categorized as subvolcanic intrusions, which lead to hydrothermal activity. A study used 2D seismic reflection data, to characterize the structures of these systems, which are sunken in craters with a funneled side profile. These structures are often referred to as chimneys which form over the surface of the vents. The oceanic crust and the seawater interact to form these systems, and alter the local chemistry and form deposits that are rich in varying metals.
==== Commercial ==== WNCB-FM (93.9 B939 FM, Country) WQDR-FM (94.7QDR, Country) WDCG-HD2 (ALT 95.3, Throwback Hits, analog broadcast on 95.3 FM W237BZ) WBBB-FM 96.1 (Radio 96.1, Adult hits) WPLW-FM (96.9 Pulse FM, Contemporary hits) WQOK-FM (K97.5, Hip hop) WRDU-FM (100.7, Classic rock) WRAL-FM (Mix 101.5, Adult contemporary) WKIX-FM (KIX 102.9, Classic hits) WNNL-FM (103.9 The Light, Urban contemporary gospel) WDCG-FM (G105, Contemporary hit radio) WTKK-FM (106.1 FM, News/Talk) WFXC-FM/WFXK-FM (Foxy 107/104, Urban adult contemporary) WQDR-AM (570, classic rock) WPTF-AM (NewsRadio 680, News/Talk) 750 WAUG (Hot 97.9, Mainstream urban WKIX (Just Right Radio 850 and 93.5 FM, Popular standards)
==== MeSH D06.472.910 – thymus hormones ==== MeSH D06.472.910.750 – thymic factor, circulating MeSH D06.472.910.800 – thymopoietins MeSH D06.472.910.800.850 – thymopentin MeSH D06.472.910.850 – thymosin
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.
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.