This is a working overview of tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-05 and is reviewed periodically as new material appears.
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.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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 a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
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.
| 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 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.
Bevan later appears on television defending the government while acknowledging her own role in supporting Tender. After Henry is arrested and agrees to testify, he contacts Bevan about possible Russian intelligence involvement in Tender’s operations; she attempts to escalate the matter to the prime minister but is warned by the chief of staff against pursuing it further, due to the potential diplomatic ramifications and the credibility of Bevan's sources.
Guinness Draught, the standard draught beer sold in kegs (but exist also a texture-like version in widget cans and bottles): 4.1 to 4.3% alcohol by volume (ABV); the Extra Cold is served through a super cooler at 3.5 °C (38.3 °F). Guinness Original/Extra Stout: 4.2 or 4.3% ABV in Ireland and the United Kingdom, 4.1% in Germany, 5.0% in continental Europe and Scandinavia (such as Sweden), 4.8% in Namibia and South Africa, 5.6% in the United States and Canada, and 6% in Australia and Japan. Guinness Foreign Extra Stout: 7.5% ABV version sold in Europe, Africa, the Caribbean, Asia, and the United States. The basis is an unfermented but hopped Guinness wort extract shipped from Dublin, which is added to local ingredients and fermented locally. The strength can vary, for example, it is sold at 5% ABV in China, 6.5% ABV in Jamaica and East Africa, 6.8% in Malaysia, 7.5% in the United States, and 8% ABV in Singapore. In Nigeria a proportion of sorghum is used. Foreign Extra Stout is blended with a small amount of intentionally soured beer. Formerly, it was blended with beer that soured naturally as a result of fermenting in ancient oak tuns with a Brettanomyces population; it is now made with pasteurised beer that has been soured bacterially. It was previously known as West Indies Porter, then Extra Stout and finally Foreign Extra Stout. It was first made available in the UK in 1990. Guinness Special Export Stout, Commissioned by John Martin of Belgium in 1912. The first variety of Guinness to be pasteurised, in 1930. 8% ABV.
Echoing this caution, Divakar and Crespo emphasise that maximum‑likelihood pipelines such as RAxML and Bayesian frameworks (e.g., MrBayes, BEAST) give the most dependable results only when their outputs are compared side by side and underpinned by formal model testing; over‑interpreting a single, untested method can yield artefactual trees.
== Occurrence == Argon constitutes 0.934% by volume and 1.288% by mass of Earth's atmosphere. Air is the primary industrial source of purified argon products. Argon is isolated from air by fractionation, most commonly by cryogenic fractional distillation, a process that also produces purified nitrogen, oxygen, neon, krypton and xenon. Earth's crust and seawater contain 1.2 ppm and 0.45 ppm of argon, respectively.
Sources: en.wikipedia.org
==== Less common side effects ==== Because these drugs act on parts of the blood and blood vessels, they tend to have side effects that affect these processes. Aside from problems with hemorrhage and hypertension, less common side effects of these drugs include dry, itchy skin, hand-foot syndrome (tender, thickened areas on the skin, sometimes with blisters on palms and soles), diarrhea, fatigue, and low blood counts. Angiogenesis inhibitors can also interfere with wound healing and cause cuts to re-open or bleed. Rarely, perforations (holes) in the intestines can occur.
== Chemistry == The separation of the stereoisomers is one of the easier in organic chemistry and is described in the original patent. It involves "treatment of racemic methadone base with d-(+)-tartaric acid in an acetone/water mixture [which] precipitates almost solely the dextro-methadone levo-tartrate, and the more potent Levomethadone can easily be retrieved from the mother liquor in a high state of optical purity." There is now an asymmetric synthesis available to prepare both levomethadone (R-(−)-methadone) and dextromethadone (S-(+)-methadone).
Using purified proteins on substrates including artificial lipid bilayers and flow-based adhesion assays, his lab discovered the first heterophilic (like-unlike) receptor–counter-receptor adhesion pairs in all of cell biology, including CD2–LFA-3 and LFA-1–ICAM. The LFA-1–ICAM interaction required Mg2+, and explained the Mg2+-dependence of cell adhesion in antigen recognition. Subsequently, Springer structurally resolved the LFA-1–ICAM-1 interaction, with Mg2+ at the ligand-binding interface.
== Company structure == Following the acquisition, The Gearbox Entertainment Company operates as a studio within 2K. Gearbox Software has two additional studios in addition to its main studios in Frisco, Texas; Gearbox Studio Montreal, and Gearbox Studio Québec. After the company was bought by Take-Two, many assets were retained by Embracer such as Lost Boys, Captured Dimensions and the San Francisco publishing division which was rebranded as Arc Games alongside several titles. The Gearbox Publishing division handled by The Gearbox Entertainment Company was later absorbed into 2K following Take-Two's buyout of Gearbox.
(CH2CH2)O + H2O → HO–CH2CH2–OH The reaction also occurs in the gas phase, in the presence of a phosphoric acid salt as a catalyst. The reaction is usually carried out at about 60 °C (140 °F) with a large excess of water, in order to prevent the reaction of the formed ethylene glycol with ethylene oxide that would form di- and triethylene glycol:
Sources: en.wikipedia.org
The Salmonella Mutagenesis test (Ames test) uses multiple strains of Salmonella typhimurium that are auxotrophic to histidine to test whether a given chemical can cause mutations by observing its auxotrophic property in response to an added chemical compound. The mutation a chemical substance or compound causes is measured by applying it to the bacteria on a plate containing histidine then moving the bacteria to a new plate without sufficient histidine for continual growth. If the substance does not mutate the genome of the bacteria from auxotrophic to histidine back to prototrophic to histidine, then the bacteria would not show growth on the new plate. So by comparing the ratio of the bacteria on the new plate to the old plate and the same ratio for the control group, it is possible to quantify how mutagenic a substance is, or rather, how likely it is to cause mutations in DNA. A chemical is considered positive for Ames test if it causes mutations increasing the observed reversion rate and negative if presents similar to the control group. There is a normal, but small, number of revertant colonies expected when an auxotrophic bacteria is plated on a media without the metabolite it needs because it could mutate back to prototrophy. The chances of this are low and therefore cause very small colonies to be formed. If a mutagenic substance is added, however, the number of revertants would be visibly higher than without the mutagenic substance.
Mark Salisbury of Time Out wrote of the lead acting to be "excellent" and the crowd scenes "astonishing", while equally observing how the climax was "truly nerve-wracking". He called it "an implacable work of authority and compassion, Cry Freedom is political cinema at its best." James Sanford, however, writing for the Kalamazoo Gazette, did not appreciate the film's qualities, calling it "a Hollywood whitewashing of a potentially explosive story." Rating the film with 3 Stars, critic Leonard Maltin wrote that the film was a "sweeping and compassionate film". He did, however, note that the film "loses momentum as it spends too much time on Kline and his family's escape from South Africa". But in positive followup, he pointed out that it "cannily injects flashbacks of Biko to steer it back on course." John Simon of the National Review called Cry Freedom "grandiosely inept". In 2013, the movie was one of several discussed by David Sirota in Salon in an article concerning white saviour narratives in film.
Type I: Properdin levels are unable to be detected Type II: Properdin levels are from 1-10% in comparison to normal levels; function is intact Type III: Properdin levels are normal but the function is absent Evaluations for properdin deficiency may take place in patients with frequenct Neisserial infections with a functioning classical complement pathway (CH50). The AH50 assay is based on the lysis of unsensitized rabbit erythrocytes, however, normal results have been reported in patients with Type I properdin deficiency. Family history of X-linked inheritance should be considered. Further testing includes: Factor D Function by Hemolytic Assay, Properdin Level by ELISA, and gene sequencing to detect mutations for confirmation. Patients with Factor D deficiency or properdin deficiency are advised to receive meningococcal vaccinations and frequent evaluations for meningococcal antibodies. For those with recurring infections, prophylactic antibiotics are administered.
=== Global market === During the 2000s, Biocon established its subsidiary Biocon Biologics and substantially grew its production of existing drugs for the American and European markets. Regulatory bodies such as the American Food and Drug Administration and various European state agencies (later the European Commission) have approved Biocon for production of many such products, starting with lovastatin in 2001. Biocon's production largely focused on generics, which as of 2022 had saved European healthcare systems some €30 billion in drug costs. In the 2010s, Biocon began rapidly expanding its production and market reach. In 2008, Biocon acquired a 70% stake in German pharmaceutical company AxiCorp GmbH. The following year, Biocon established a partnered research facility in Bengaluru with American pharmaceutical corporation Bristol Myers Squibb, and announced a strategic collaboration with Mylan to enter the global generic biologics market. The following years saw a steady expansion of major Biocon production facilities in Asian nations, including Malaysia in 2010, and in Bangalone in 2016 with partner Amgen.
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.
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.