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 2026-06-24 and is reviewed periodically as new material appears.
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.
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.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
No pharmacopoeial monograph exists for this peptide, so quality rests on the supplier's internal specifications and on whatever independent testing a purchaser arranges. Certificates of analysis differ widely in which tests they report and in the limits applied. The counter-ion introduced during purification, commonly acetate or trifluoroacetate, changes the net peptide content of a given mass of powder, so two samples of equal weight may not contain equal amounts of the active sequence. Third-party laboratories can verify purity, identity, residual solvents, and counter-ion content for a fee, which makes documentation more informative than labelling.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
| 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 |
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.
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.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
（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.
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.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
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.
== War period, 1938–1945 == When the committee was outlawed in September 1937, six of its members were deported, its president Amin al-Husayni managed to escape arrest and went into exile in Beirut. Jamal al-Husayni escaped to Syria. Three other members were deported to the Seychelles, and other members moved into voluntary exile in neighbouring countries. Al-Hadi, who was out of the country at the time, was not allowed to return. Membership of the outlawed committee had dwindled to Jamal al-Husayni (acting chairperson), Husayn al-Khalidi (secretary), Ahmed Hilmi Pasha and Emil Ghuri. For all practical purposes, the committee ceased to exist, however, this brought little change in the structure of Arab political life and the Palestinian revolt continued. With the indications of a new European war on the horizon, and in an endeavor to resolve the inter-communal issues in Palestine, the British government proposed in late 1938 a conference in London of the two Palestinian communities. Some Arab leaders welcomed the proposed London Conference but indicated that the British would need to deal with the disbanded Arab Higher Committee and with Amin al-Husayni. On 23 November 1938, the Colonial Secretary, Malcolm MacDonald, repeated his refusal to allow Amin al-Husayni to be a delegate, but was willing to allow the five Palestinian leaders held in the Seychelles to take part in the conference.
=== Pregnancy === More than 75% of women with rheumatoid arthritis have symptoms that improve during pregnancy, but their symptoms worsen after delivery. Methotrexate and leflunomide are teratogenic (harmful to the fetus) and not used in pregnancy. It is recommended that women of childbearing age use contraceptives to avoid pregnancy and discontinue their use if pregnancy is planned. Low doses of prednisolone, hydroxychloroquine, and sulfasalazine are considered safe in pregnant women with rheumatoid arthritis. Prednisolone should be used with caution as the side effects include infections and fractures.
In a 2009 study of 683 children diagnosed in Beijing in 2008 with nephrolithiasis and 6,498 children without nephrolithiasis aged < 3 years, investigators found that in children exposed to melamine levels < 0.2 mg/kg per day, the risk for nephrolithiasis was 1.7 times higher than in those without melamine exposure, suggesting that the risk of melamine-induced nephrolithiasis in young children starts at a lower intake level than the levels recommended by the World Health Organization. In a study published in 2010, researchers from Beijing University studying ultrasound images of infants who fell ill in the 2008 contamination found that while most children in a rural Chinese area recovered, 12 per cent still showed kidney abnormalities six months later. "The potential for long-term complications after exposure to melamine remains a serious concern," the report said. "Our results suggest a need for further follow-up of affected children to evaluate the possible long-term impact on health, including renal function." Another 2010 follow-up study from Lanzhou University attributed the uric acid stone accumulation after ingestion of melamine to a rapid aggradation of metabolites such as cyanuric acid diamide (ammeline) and cyanuric acid and reported that urine alkalinization and stone liberalization were the most effective treatments. Until the 2007 pet food recalls, melamine had not routinely been monitored in food, except in the context of plastic safety or insecticide residue.
==== Essential oils ==== Many essential oils included in herbal pharmacopoeias are claimed to possess antimicrobial activity in vitro, with the oils of bay, cinnamon, clove and thyme reported to be the most potent in studies with foodborne bacterial pathogens. While 25 to 50% of pharmaceutical compounds are plant-derived, none are used as antimicrobials, though there has been increased research in this direction. Barriers to increased usage in mainstream medicine include poor regulatory oversight and quality control, evidence only from in vitro studies, mislabeled or misidentified products, and limited modes of delivery.
Sources: en.wikipedia.org
Unlike most wealthy OECD countries, Australian law enables employers to not provide all rights of employment, particularly paid holidays and job security, if people are classed as "casual" employees, and in 2023 this meant around 22% of employees. To compensate for the absence of rights, modern awards typically grant a 25% "casual loading" additional pay, but potentially no holidays at all, putting Australia at odds with European Union practice There is also no legal mechanism to prevent employers rates of pay before the 25% loading is added. Under the Fair Work Act 2009 section 15A a casual employee exists if the relationship has an "absence of a firm advance commitment to continuing and indefinite work", replacing the previous notion that an employee simply accepts they do in a contract. This reversed the decision of the High Court in Workpac Pty Ltd v Rossato, that where a contract states someone is casual, even if the employer is providing them with ongoing work in regular and systematic shifts in reality, they are still casual employees and not entitled to paid holidays under FWA 2009 section 86. Casual workers are protected by unfair dismissal after 6 months, or 12 months for a small business, if they are deemed to work 'on a regular and systematic basis' and have a reasonable expectation of continued employment, but otherwise risk losing job security rights. Since 2021 casual workers must get an offer of a permanent contract offer after 12 months unless there are reasonable grounds to not make the offer.
The medial position (base) in this molecule (the isomer [1(2,3)4]pentamantane) is calculated to yield a more favorable carbocation than the apical position (top) and simple bromination of pentamantane 1 with bromine exclusively gives the medial bromo derivative 2 which on hydrolysis in water and DMF forms the alcohol 3.
MuscleTech is a brand of dietary supplements, marketed by Iovate Health Sciences Inc., which includes Hydroxycut. It was owned by Canadian company Kerr Holdings which was acquired by Xiwang Foodstuffs Company, a Chinese company, for $584 million in 2016.
Following the fall of the Republic in April 1939, the president of Spain, Manuel Azaña and the prime minister, Juan Negrín, went into exile in France. Azaña resigned his post and died in November 1940. He was succeeded as president by Diego Martínez Barrio, who had been prime minister in 1936. Following the German occupation of France in 1940, the government was reconstituted in Mexico, which under the left-wing president Lázaro Cárdenas continued to recognise the Republic, although Negrín spent the World War II years in London. Negrín resigned as prime minister in 1945 and was succeeded by José Giral. Until 1945, the exiled Republicans had high hopes that at the end of World War II in Europe, Franco's regime would be removed from power by the victorious Allies and that they would be able to return to Spain. Furthermore, the newly-established United Nations would pass a resolution condemning the Francoist regime and the exiled Republicans initially worked with the Allies. When these hopes were disappointed, the government-in-exile faded away to a purely symbolic role. The government moved back to Paris in 1946. There was also a Basque government-in-exile and a Catalan government-in-exile. In the immediate postwar period, it had diplomatic relations with Mexico, Panama, Guatemala, Venezuela, Poland, Czechoslovakia, Hungary, Yugoslavia, Romania, and Albania, but the United States, the United Kingdom, France and the Soviet Union did not recognise it. Following Franco's death in 1975, King Juan Carlos initiated a transition to democracy.
=== Culinary === Potassium alum may be an acidic ingredient of baking powder to provide a second leavening phase at high temperatures (although sodium alum is more commonly used for that purpose). For example, potassium alum is frequently used in leavening of youtiao, a traditional Chinese fried bread, throughout China. Alum was used by bakers in England during the 1800s to make bread whiter. This was theorized by some, including John Snow, to cause rickets. The Sale of Food and Drugs Act 1875 (38 & 39 Vict. c. 63) prevented this and other adulterations. Potassium alum, under the name "alum powder", is found in the spice section of many grocery stores in the US. Its chief culinary use is in pickling recipes, to preserve and add crispness to fruit and vegetables.
Sources: en.wikipedia.org
Proteinase K will not be inhibited by Guanidinium chloride, Guanidinium thiocyanate, urea, Sarkosyl, Triton X-100, Tween 20, SDS, citrate, iodoacetic acid, EDTA or by other serine protease inhibitors like Nα-Tosyl-Lys Chloromethyl Ketone (TLCK) and Nα-Tosyl-Phe Chloromethyl Ketone (TPCK). Protease K activity in commonly used buffers
== Nearly defunct former casual restaurant chains == This list contains chains that were much larger in the past, with some having several hundred locations at their peak, which have since been reduced to a single location.
== Skyscrapers == The German building research firm Emporis ranks world cities by the number of their skyscrapers. Emporis defines a skyscraper as "...any multilevel building with an architectural height of at least 100 metres." Bangkok ranks number seven of the 100 cities with the most skyscrapers. Bangkok has 376. Other ASEAN cities listed are Singapore, ranked 4 with 506 skyscrapers; Kuala Lumpur, ranked 14 with 202; Jakarta, ranked 17 with 181; Hanoi, ranked 36 with 120; Ho Chi Minh City, ranked 43 with 103; and Manila, ranked 93 with 37 skyscrapers.
== Affiliated hospitals == Rajindra Hospital, Patiala with 1009 beds was attached to the college in early 1951. The hospital was equipped with all the latest apparatus and instruments to make it fit for imparting clinical teaching to the students. Two well designed, spacious and well lighted lecture theatres equipped with arrangements for epidiascopes projections and audio visual aids were provided on the hospital side in addition to four lecture theatres of similar design on college side for basic departments. The department of Tuberculosis and Respiratory Medicine/Pulmonary Medicine is located in a separate campus, known as the Tuberculosis Centre, Patiala which started functioning on 25 July 1953 with 22 observation beds, 11 for male and 11 for female patients with Tuberculosis. It is popularly known as TB Hospital or Padma Shri Dr. Khushdeva Singh Chest Diseases Hospital, and currently has a capacity of 121 beds. Primary health centres at Bhadson, Kauli and Tripuri are attached with this college for teaching purposes. There are three hostels, two for girls and one for boys. In addition to this there is one hostel in the Rajindra Hospital also for Doctors/Interns/House surgeons. The college has a very spacious auditorium, big play ground and an open-air theatre. The college is governed by Director Research and Medical Education, Punjab and is affiliated to Baba Farid University of Health Sciences, Faridkot.
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.
Mass spectrometry provides the identity check, because the observed mass is compared with the theoretical mass of the AEDG sequence. Chromatography separates and quantifies impurities but does not by itself prove which peptide is present. The two techniques are normally used together.