This is a working overview of Tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-03-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Ala-Glu-Asp-Gly | Often abbreviated AEDG in research literature |
| Common synonyms | Epithalon, epitalon, AEDG | Spelling variants refer to the same tetrapeptide |
| Molecular formula | C14H22N4O9 | Theoretical monoisotopic mass near 390.35 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilised solid |
| Solubility class | Freely soluble in water | Hydrophilic peptide; dissolves in aqueous buffer |
transuranic elements Also transuranium elements. The set of chemical elements with an atomic number greater than 92, i.e. occurring after uranium in the periodic table. None of the transuranic elements are stable in naturally occurring conditions.
=== Malaria === A number of different proteins on the surface of Plasmodium falciparum malaria parasites help the invaders bind to red blood cells. But once attached to host blood cells, the parasites need to shed the 'sticky' surface proteins that would otherwise interfere with entrance into the cell. The Sheddase enzyme, specifically called PfSUB2 in this example, is required for the parasites to invade cells; without it, the parasites die. The sheddase is stored in and released from cellular compartments near the tip of the parasite, according to the study. Once on the surface, the enzyme attaches to a motor that shuttles it from front to back, liberating the sticky surface proteins. With these proteins removed, the parasite gains entrance into a red blood cell. The entire invasion lasts about 30 seconds and without this ADAM metallopeptidase, malaria would be ineffective at invading the red blood cells.
Modern forensic chemists rely on numerous instruments to identify unknown materials found at a crime scene. The 20th century saw many advancements in technology that allowed chemists to detect smaller amounts of material more accurately. The first major advancement in this century came during the 1930s with the invention of a spectrometer that could measure the signal produced with infrared (IR) light. Early IR spectrometers used a monochromator and could only measure light absorption in a very narrow wavelength band. It was not until the coupling of an interferometer with an IR spectrometer in 1949 by Peter Fellgett that the complete infrared spectrum could be measured at once. Fellgett also used the Fourier transform, a mathematical method that can break down a signal into its individual frequencies, to make sense of the enormous amount of data received from the complete infrared analysis of a material. Since then, Fourier transform infrared spectroscopy (FTIR) instruments have become critical in the forensic analysis of unknown material because they are nondestructive and extremely quick to use. Spectroscopy was further advanced in 1955 with the invention of the modern atomic absorption (AA) spectrophotometer by Alan Walsh. AA analysis can detect specific elements that make up a sample along with their concentrations, allowing for the easy detection of heavy metals such as arsenic and cadmium. Advancements in the field of chromatography arrived in 1953 with the invention of the gas chromatograph by Anthony T.
=== In-orbit activities === At the start of the third orbit, Cooper checked his list of 11 experiments that were on his schedule. His first task was to eject a six-inch (152 mm) diameter sphere, equipped with xenon strobe lights, from the nose of the spacecraft. This experiment was designed to test his ability to spot and track a flashing beacon in orbit. At T+3 hours 25 minutes, Cooper flipped the switch and heard and felt the beacon detach from the spacecraft. He tried to see the flashing light in the approaching dusk and on the nightside pass, but failed to do so. On the fourth orbit, he did spot the beacon and saw it pulsing. Cooper reported to Scott Carpenter on Kauai, Hawaii, "I was with the little rascal all night." He also spotted the beacon on his fifth and sixth orbits. Also on the sixth orbit, at about T+9 hours, Cooper set up cameras, adjusted the spacecraft attitude and set switches to deploy a tethered balloon from the nose of the spacecraft. It was a 30-inch (762 mm) PET film balloon painted fluorescent orange, inflated with nitrogen and attached to a 100-foot (30 m) nylon line from the antenna canister. A strain gauge in the antenna canister would measure differences in atmospheric drag between the 100-mile (160 km) perigee and the 160-mile (260 km) apogee. Cooper tried several times to eject the balloon, but it failed to eject. Cooper passed Schirra's orbital record on the seventh orbit while he was engaged in radiation experiments. After 10 hours, the Zanzibar tracking station informed Cooper the flight was a go for 17 orbits.
==== Hypoglycemia ==== An acute hypoglycemic episode (very low blood sugar) can happen to even careful pet owners, since cats' insulin requirements sometimes change without warning. The symptoms include depression/lethargy, confusion/dizziness, loss of excretory/bladder control, vomiting, and then loss of consciousness and/or seizures. Immediate treatment includes administering honey or corn syrup by rubbing on the gums of the cat (even if unconscious, but not if in seizures). Symptomatic hypoglycemia in cats is a medical emergency and the cat will require professional medical attention. The honey/corn syrup should continue to be administered on the way to the vet, as every minute without blood sugar causes brain damage. A cat with hypoglycemia according to a human-calibrated blood glucose meter (<2.2 mmol/L or 40 mg/dL), but with no symptoms, should be fed as soon as possible. Hypoglycemic cats that refuse to eat can be force-fed honey or corn syrup until they stabilize, though this may not be done if the animal is unconscious or having a seizure, as the liquid is likely to enter the animal's lungs and cause choking and asphyxiation. Mild hypoglycemic episodes can go unnoticed or leave evidence such as urine pools outside the litter box. In these cases the blood sugar will probably appear paradoxically high upon the next test hours later, since the cat's body will react to the low blood sugar by stimulating the liver to release stored glycogen.
Sources: en.wikipedia.org
Noted for his longevity in the game, Fletcher played a total of 400 senior VFL/AFL games, which stands as the fifth-highest number of games by any player as of 2023. His AFL career length of 22 years and 58 days is an all-time league record (edging out Vic Cumberland, whose former record was five days shy of 22 years). Fletcher played his 400th game in Round 9, 2015, becoming the third player in VFL/AFL history to reach the milestone (after Michael Tuck and Kevin Bartlett); it would end up being his final game, as he was unable to recover from a groin injury sustained during the match. He holds the outright Essendon games record, having overtaken the previous record of 378 games held by Simon Madden in Round 1, 2014. He is the second-oldest player to play a VFL/AFL game, aged 40 years and 23 days at the time of his final game, behind only the aforementioned Vic Cumberland (who played the 1920 season at the age of 43). With his father, Ken, the Fletchers hold the record for the most VFL/AFL career games played by a father and son, with 664 games between them. On 12 January 2016, during the summer after his retirement, Fletcher was named as one of 34 past and present Essendon players found guilty over their use of illegal supplements during the 2012 AFL season. As a result, Fletcher was suspended from playing at all levels for 24 months, which with backdating and provisional suspension served resulted in suspension until November 2016. However, Fletcher had already retired the previous year, so the suspension was moot.
=== Withdrawal === The incidence of antidepressant discontinuation syndrome symptoms in men using dapoxetine to treat PE has been described by reviewers as low or no different from the incidence of such symptoms in men withdrawn from placebo treatment. The lack of chronic serotonergic stimulation with on-demand dapoxetine minimizes the potentiation action of serotonin at synaptic cleft, thus decreasing the risk of discontinuation symptoms.
August 1: Helsinki Final Act of the Conference on Security and Co-operation in Europe signed by the United States, Canada, the Soviet Union and Europe. October 9: Andrei Sakharov is awarded the Nobel Peace Prize. October 30: Western Sahara War begins between Morocco, Mauritania and Polisario Front. November: Operation Condor begins in South America. November 11: The Angolan Civil War begins immediately after Angola achieved independence from Portugal. November 20: Francisco Franco dies, and under Juan Carlos I, Spain becomes a democracy. November 25: Suriname officially gains independence from the Kingdom of the Netherlands. November 28: After a small-scale civil war, Timor-Leste under the Fretilin declares its independence. November 29: Pathet Lao takes power in Laos. December 7: In Operation Seroja, the Indonesian National Armed Forces invades East Timor. The day before, US President Gerald Ford had given the green light for the invasion in a meeting with Indonesian President Suharto in Jakarta. An estimated 100,000–180,000 people will be killed or starve to death in the 25-year occupation.
=== Mechanotransductive === Additionally, YAP is regulated by mechanical cues such as extracellular matrix (ECM) rigidity, strain, shear stress, or adhesive area, processes that are reliant on cytoskeletal integrity. These mechanically induced localization phenomena are thought to be the result of nuclear flattening induced pore size change, mechanosensitive nuclear membrane ion channels, mechanical protein stability, or a variety of other factors. These mechanical factors have also been linked to certain cancer cells via nuclear softening and higher ECM stiffnesses. Under this framework, the nuclear softening phenotype of cancer cells would promote nuclear flattening in response to a force, causing YAP localization, which could explain its over-expression and promoted proliferation in oncogenic cells. Additionally, the higher ECM stiffness phenotype commonly seen in tumors due to enhanced integrin signaling could flatten the cell and nucleus, once again causing higher YAP nuclear localization. Likewise, the opposite effect of nuclear stiffening as a result of a variety of stimuli such as an over-expression of lamin A, has been shown to decrease nuclear YAP localization.
Sources: en.wikipedia.org
== Material advances == Recent advances in out of autoclave (OOA) processes hold promise for improving performance and lowering costs for composite structures. Using vacuum-bag-only (VBO) for atmospheric pressures, the new OOA processes promise to deliver less than 1 percent void content required for aerospace primary structures. Led by material scientists at Air Force Research Lab, the technique would save the costs of constructing and installing large structure autoclaves ($100M saved at NASA) and making small production runs of 100 aircraft economically viable.
A vacuum pump is a type of pump device that draws gas particles from a sealed volume in order to leave behind a partial vacuum. The first vacuum pump was invented in 1650 by Otto von Guericke, and was preceded by the suction pump, which dates to antiquity.
Emma Schymanski (née Craven) is an Australian chemist known for her work identifying unknown organic compounds, particularly pollutants, and is an advocate for open science. She is currently a Professor of Cheminformatics at the University of Luxembourg.
Caveolae-associated protein 2 or Cavin-2 is a protein that in humans is encoded by the CAVIN2 gene (previously SDPR). Cavin-2 is highly expressed in a variety of human endothelial cells. This gene has a calcium-independent phospholipid-binding protein whose expression increases in serum-starved cells. This protein has also been shown to be a substrate for protein kinase C (PKC) phosphorylation.
== Gas-phase reactions == One of the oldest known chemiluminescent reactions is that of elemental white phosphorus oxidizing in moist air, producing a green glow. This is a gas-phase reaction of phosphorus vapor, above the solid, with oxygen producing excited states of (PO)2 and HPO. Another gas phase reaction is the basis of nitric oxide detection in commercial analytic instruments applied to environmental air-quality testing. Ozone (O3) is combined with nitric oxide (NO) to form nitrogen dioxide (NO2) in an activated state [◊]:
Sources: en.wikipedia.org
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.
No. Epithalamin is a peptide-rich extract prepared from bovine pineal glands, while epitalon is a short synthetic peptide designed as a defined analogue of it. The synthetic version was intended to provide a reproducible molecule with some of the same proposed biological activity.
Telomere elongation and telomerase activation have been reported in cultured human somatic cells, but evidence from living human subjects is limited and has not been independently confirmed at scale. Reported findings come largely from small studies with differing designs, so the question remains open rather than settled.
The peptide contains four residues in the order alanine, glutamate, aspartate and glycine, abbreviated AEDG. The chain is linear and held together by three peptide bonds. Its calculated mass for the uncharged free form is about 390.3 daltons.