The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
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.
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.
| 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 |
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.
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.
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.
Kuwait had been a part of the Ottoman Empire's province of Basra, something that Iraq claimed made Kuwait rightful Iraqi territory. Kuwait's ruling dynasty, the al-Sabah family, had concluded a protectorate agreement in 1899 that assigned responsibility for Kuwait's foreign affairs to the United Kingdom. The UK drew the border between Kuwait and Iraq in 1922, making Iraq almost entirely landlocked. Kuwait rejected Iraqi attempts to secure further provisions in the region. Iraq also accused Kuwait of exceeding its OPEC quotas for oil production. In order for the cartel to maintain its desired price of $18 per barrel, discipline was required. The United Arab Emirates and Kuwait were consistently overproducing; the latter at least in part to repair losses caused by Iranian attacks in the Iran–Iraq War and to pay for the losses of an economic scandal. The result was a slump in the oil price – as low as $10 per barrel ($63/m3) – with a resulting loss of $7 billion a year to Iraq, equal to its 1989 balance of payments deficit. Resulting revenues struggled to support the government's basic costs, let alone repair Iraq's damaged infrastructure. Jordan and Iraq both looked for more discipline, with little success. The Iraqi government described it as a form of economic warfare, which it claimed was aggravated by Kuwait slant-drilling across the border into Iraq's Rumaila oil field.
== See also == Plasmid Viral vector Cloning vector Expression vector Hybrid vector Minicircle Recombinant DNA Naked DNA Vector (epidemiology), an organism that transmits disease Human artificial chromosomes Yeast artificial chromosomes Bacterial artificial chromosomes DNA vaccination
Boehringer Ingelheim Austria has validated a method with cGMP (commercial good manufacturing practices) for production of pharmaceutical-grade DNA plasmids. They are able to process 200L of fermentation broth on an 800mL monolith. At BIA Separations, processing time of the tomato mosaic virus decreased considerably from the standard five days of manually intensive work to equivalent purity and better recovery in only two hours with a monolith column. Other viruses have been purified on monoliths as well. Affinity monoliths have also been applied to the isolation of nanoscale particles from human plasma. Tandem monolithic disks functionalized with chondroitin-6-sulfate and anti-apolipoprotein B-100 antibodies enabled the selective isolation of low-density lipoprotein in less than 30 minutes, while a monolith carrying an anti-CD61 antibody isolated platelet-derived extracellular vesicles in 19 minutes. Monolithic disks carrying antibodies against apoB-100, CD9, or CD61 were subsequently coupled online to asymmetric flow field-flow fractionation, allowing automated isolation and size fractionation of lipoproteins and extracellular-vesicle subpopulations. Extracellular-vesicle fractions obtained using these monolith-based systems have also been characterized by Raman spectroscopy and comprehensive two-dimensional gas chromatography, and used in quartz crystal microbalance studies of binding between extracellular-vesicle subpopulations and affinity ligands.
=== 1991 === 11 August After Desert Storm, the technology deployed in the Gulf War, and whether any lessons were learned - featured Major General Sir Peter de la Billière, Commander of the British Forces in the Gulf; a 66-foot-long F117 at King Khalid Air Base at Khamis Mushait on 16 January 1991 - the aircraft had no radar, but had the radar signature of a small bird; F117 pilot Major Greg Feest; Air Vice-Marshal Bill Written, the air commander of British Forces Middle East from November 1990; Colonel John A.
Chem. Int. Ed. 2017, 56, 16018-16022. https://doi.org/10.1002/anie.201709463. M, Hifsudheen.; R, K, Mishra.; B, Vedhanarayanan.; V, K, Praveen.; and Ajayaghosh, Ayyappanpillai (2017). “Helix to Super-Helix Transition in p-Systems Self-assembly: Superseding of Molecular Chirality at Hierarchical Level”. Angew. Chem., Int. Ed. 2017, 56, 12634-12638. https://doi.org/10.1002/anie.201707392. S, Ghosh.; S, Cherumukkil.; C, H, Suresh.; and Ajayaghosh, Ayyappanpillai (2017). “A Supramolecular Nanocomposite as Near Infrared Transmitting Optical Filter for Security and Forensic Applications”. Adv. Mater. 2017, 29, 1703783.doi:10.1002/adma.201703783 A, Mal.; R, K, Mishra.; V, K, Praveen.; M, A, Khayum.; R, Banerjee.; and Ajayaghosh, Ayyappanpillai (2018). “Supramolecular Reassembly of Self-Exfoliated Ionic Covalent Organic Nanosheets for Label-Free Detection of dsDNA”. Angew. Chem., Int. Ed. 2018, 57, 8443. https://doi.org/10.1002/anie.201801352. R, D, Mukhopadhyay.; G, Das.; and Ajayaghosh, Ayyappanpillai (2018). “Stepwise Control of Host-Guest Interaction Using a Coordination Polymer Gel”. Nat. Commun. 2018, 9, 1987. https://doi.org/10.1038/s41467-018-04303-8. V, K, Praveen.; B, Vedhanarayanan.; A, Mal.; R, K, Mishra.; and Ajayaghosh Ayyappanpillai (2020). “Self-Assembled Extended p‑Systems for Sensing and Security Applications”. Acc. Chem. Res. 2020, 53, 2, 496-507. https://doi.org/10.1021/acs.accounts.9b00580 S, Chakraborty.; M, M, Joseph.; S, Varughese.; S, Ghosh.; K, K, Maiti.; A, Samanta.; and Ajayaghosh, Ayyappanpillai (2020).
Sources: en.wikipedia.org
Dehydroascorbate, the oxidized form, is then recycled back to ascorbate by endogenous antioxidants such as glutathione. In the eye, ascorbate is thought to protect against photolytically generated free-radical damage; higher plasma ascorbate is associated with lower risk of cataracts. Ascorbate may also provide antioxidant protection indirectly by regenerating other biological antioxidants such as α-tocopherol back to an active state. In addition, ascorbate is also a non-enzymatic reducing agent for mixed-function oxidases in the microsomal drug-metabolizing system that inactivates a wide variety of substrates such as drugs and environmental carcinogens.
Upon inhibition of the receptor, downstream signaling causes dopamine and norepinephrine release, and the receptor is thought to significantly regulate mood, anxiety, feeding, and reproductive behavior. 5-HT2C receptors regulate dopamine release in the striatum, prefrontal cortex, nucleus accumbens, hippocampus, hypothalamus, and amygdala, among others. Research indicates that some suicide victims have an abnormally high number of 5-HT2C receptors in the prefrontal cortex. There is some mixed evidence that agomelatine, a 5-HT2C antagonist, is an effective antidepressant. Antagonism of 5-HT2C receptors by agomelatine results in an increase of dopamine and norepinephrine activity in the frontal cortex.
=== South Pacific === Australia: BCG vaccination was used between the 1950s and mid-1980s. BCG has not been part of routine vaccination since the mid-1980s. New Zealand: BCG Immunisation was first introduced for 13-year-olds in 1948. Vaccination was phased out from 1963 to 1990.
Abuse of fenethylline using the former brand name Captagon is common in the Middle East, and counterfeit versions of the drug continue to be available despite its illegality. Fenethylline is much less common outside of the Middle East, to the point that police may not recognize the drug. Fenethylline production and export were a significant industry sponsored by Bashar al-Assad's government, with revenue from its exports contributing more than 90% of its foreign currency. After the fall of al-Assad's government in Syria, Captagon trade fell by around 90%. The Assad regime's annual fenethylline revenues were estimated to have been worth US$57 billion in 2022, about three times the total trade of the entire Mexican illicit drug market. Later research demonstrated that this assistance, largely the financing of production and sponsoring networks of drug dealers, was undertaken through the former Assad regime's Military Intelligence Directorate (Syria). In July 2019 in Lebanon, captagon was sold for $1.50 to $2.00 a pill. In 2021 in Syria, low-quality pills were sold locally for less than $1, while high-quality pills are increasingly smuggled abroad and may cost upwards of $14 each in Saudi Arabia. Many of these counterfeit "Captagon" tablets contain other amphetamine derivatives that are easier to produce, but are pressed and stamped to look like Captagon pills. Some counterfeit Captagon pills analysed do contain fenethylline, indicating that illicit production of the drug continues to take place.
Sources: en.wikipedia.org
Usually, each segment in a chain (which is constructed from riveted metal sections similar to a bicycle chain, but without rollers) features small, sharp, cutting teeth. Each tooth takes the form of a folded tab of chromium-plated steel with a sharp angular or curved corner and two beveled cutting edges, one on the top plate and one on the side plate. Left-handed and right-handed teeth are alternated in the chain. Chains are made in varying pitch and gauge; the pitch of a chain is defined as half of the length spanned by any three consecutive rivets (e.g., 8 mm, 0.325 inch), while the gauge is the thickness of the drive link where it fits into the guide bar (e.g., 1.5 mm, 0.05 inch). The conventional "full complement" chain has one tooth for every two drive links. "Full skip" chain has one tooth for every three drive links. Built into each tooth is a depth gauge or "raker", which rides ahead of the tooth and limits the depth of cut, typically to around 0.5 mm (0.025"). Depth gauges are critical to safe chain operation. If left too high, they cause very slow cutting; if filed too low, the chain becomes more prone to kick back. Low depth gauges also cause the saw to vibrate excessively. Vibration is uncomfortable for the operator and is detrimental to the saw.
== History == 麹 (Chinese: qū, Japanese: kōji), which means mold used in fermented foods, was first mentioned in the Zhouli (Rites of the Zhou dynasty) in China in 300 BCE. Its development is a milestone in Chinese food technology, for it provides the conceptual framework for three major fermented soy foods: soy sauce, jiang/miso, and douchi, not to mention grain-based wines (including Japanese sake and Chinese huangjiu) and li (the Chinese forerunner of Japanese amazake). The process of making rice wine and fermented bean paste using molds was first documented in the 4th century B.C. In 725 AD the Japanese book Harima no Kuni Fudoki (Geography and Culture of the Harima Province) first mentioned kōji outside of China and described that the Japanese produced kōji with fungal spores from the air. Around the 10th century, the kōji production method underwent a change and moved from the natural sowing system in rice to the so-called tomodane. This involved cultivating kōji until spores were released and using the spores to start a new batch of production. In the Meiji era, the integration of new microbiological techniques made it possible to isolate and propagate kōji in pure cultures for the first time. These advances facilitated the improvement of fungal culture quality and the selection of desirable characteristics. It later became known that Kōji comprises different species of Aspergillus. Aspergillus oryzae was first described in 1878 as Eurotium oryzae Ahlb. and in 1883 as Aspergillus oryzae (Ahlb.) Cohn.
MS1 is a positive allosteric modulator (PAM) of the μ-opioid receptor (MOR). It was developed from structural modification of the earlier MOR PAM BMS‐986122. The drug has been found to augment the affinity of the MOR agonist levomethadone ((R)-methadone) for the MOR by 7-fold in vitro and to potentiate activation of the MOR by levomethadone by 4-fold in a G protein assay. However, MS1 displays strong probe dependence, and while it potentiates the MOR agonists levomethadone and morphine, it had no effect on the affinity or potency of the MOR agonists DAMGO or endomorphin-1. MS1 shows a preference for β-arrestin recruitment over G protein activation with endomorphin-1 exposure. The drug's actions are reportedly similar to those of BMS-986122, though its unclear if their mechanisms of action are the same. MS1 shows potentiated analgesic effects with opioids in animals. It also did not worsen opioid withdrawal symptoms, respiratory depression, or analgesic tolerance. MS1 and other atypical MOR activators are of potential interest in the development of novel opioid analgesics with reduced adverse effects and misuse potential. MS1 has notably been found to penetrate the blood–brain barrier in animals. The potential of the related MOR PAMs BMS-986121 and BMS-986122 as pharmaceutical drugs has been restricted owing to their complex chemical synthesis. MS1 has a much simpler synthesis in comparison and hence has been regarded as having overcome this limitation. MS1 was first described in the scientific literature by 2015.
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.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.