The short version of Tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
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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.
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
| 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 |
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.
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.
Proposed mechanisms centre on cell-culture observations rather than a defined receptor interaction. Several reports describe increased expression of the telomerase catalytic subunit after exposure of cultured human cells, and the authors attributed the effect to short peptide fragments entering the nucleus and influencing gene transcription. No receptor for the tetrapeptide has been identified, and the free peptide is expected to be degraded rapidly by plasma peptidases. Whether any measurable fraction reaches intact tissues after administration remains an unresolved question rather than an established finding.
The published literature is dominated by a small number of research groups, much of it in Russian-language journals, and independent replication outside those groups is limited. Studies are typically small, use cultured cells or rodent models, and report endpoints that differ between papers, which makes comparison difficult. Large randomised human trials have not appeared in the indexed literature. Questions about absorption, distribution and clearance are therefore still treated as open in reviews that mention the compound.
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.
Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast, prokaryotes (bacteria and archaea) store their DNA only in the cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.
==== Low-temperature process ==== Low-temperature processing also plays an essential role in food processing and storage. During this process, microorganisms and enzymes are subjected to low temperatures. Unlike heating, chilling does not destroy the enzymes and microorganisms but simply reduces their activity, which is effective as long as the temperature is maintained. As the temperature is raised, activity will rise again accordingly. It follows that, unlike heating, the effect of preservation by cold is not permanent; hence the importance of maintaining the cold chain throughout the shelf life of the food product. There are two distinct low temperature processes: chilling and freezing. Chilling is the application of temperatures within the range of 0-8 °C, while freezing is usually below 18 °C. Refrigeration does slow spoilage in food and reduce the risk of bacterial growth, however, it does not improve the quality of the product.
=== Judges' Costumes === Episode 1: Carla Hall as a bloody victim, Zac Young as Chucky, Stephanie Boswell as the final girl Episode 2: Carla Hall and Stephanie Boswell as terrifying twins (inspired by the Grady Twins from The Shining), Zac Young as an archaeologist (inspired by Indiana Jones) Episode 3: Carla Hall as an evil cheerleader, Zac Young as a vampire glam rock star, Stephanie Boswell as Mistress of the Dark (inspired by Elvira) Episode 4: Carla Hall as an undead fitness instructor, Zac Young as a voodoo doll, Stephanie Boswell as goblin king (inspired by Jareth from the 1986 movie Labyrinth) Episode 5: Carla Hall as dancing queen who only made it to seventeen, Zac Young as tuxedo wolfman, Stephanie Boswell as bloody prom queen (inspired by Carrie White) Episode 6: Carla Hall as deadly disco queen, Zac Young as vicious poodle, Stephanie Boswell as creepy clown Episode 7: Carla Hall as cat lady, Zac Young as devilish boss, Stephanie Boswell as Dollface
The hysteresis of a hydrogel refers to the phenomenon where there is a delay in the deformation and recovery of a hydrogel when it is subjected to mechanical stress and relieved of that stress. This occurs because the polymer chains within a hydrogel rearrange, and the water molecules are displaced, and energy is stored as it deforms in mechanical extension or compression. When the mechanical stress is removed, the hydrogel begins to recover its original shape, but there may be a delay in the recovery process due to factors like viscoelasticity, internal friction, etc. This leads to a difference between the stress-strain curve during loading and unloading. Hysteresis within a hydrogel is influenced by several factors including composition, crosslink density, polymer chain structure, and temperature. The toughness and hysteresis of a hydrogel are especially important in the context of biomedical applications such as tissue engineering and drug delivery, as the hydrogel may need to withstand mechanical forces within the body, but also maintain mechanical performance and stability over time. Most typical hydrogels, both natural and synthetic, have a positive correlation between toughness and hysteresis, meaning that the higher the toughness, the longer the hydrogel takes to recover its original shape and vice versa. This is largely due to sacrificial bonds being the source of toughness within many of these hydrogels.
Sources: en.wikipedia.org
== Interactions == A combination of ACE inhibitor with other drugs may increase effects of these drugs, but also the risk of adverse effects. Commonly reported adverse effects of drug combination with ACE inhibitor are acute renal failure, hypotension, and hyperkalemia. Drugs interacting with ACE inhibitor should be prescribed with caution. Special attention should be given to combinations of ACE inhibitor with diuretics (especially potassium-sparing diuretics), NSAIDs, anticoagulants, cyclosporine, DPP-4 inhibitors, and potassium supplements Angiotensin II receptor antagonists (ARBs) should not be used with ACE inhibitors. Dual RAAS inhibitor therapy (ACE inhbitors, ARBs, direct renin inhibitors, or mineralocorticoid receptor antagonists) has been found to significantly increase the risk of developing kidney damage and hyperkalemia. Potassium supplementation should be used with caution and under medical supervision owing to the hyperkalemic effect of ACE inhibitors. Concomitant use with cyclooxygenase inhibitors tends to decrease ACE inhibitor's hypotensive effect.
=== Stress === Smokers report higher levels of everyday stress. Several studies have monitored feelings of stress over time and found reduced stress after quitting. The deleterious mood effects of everyday between-cigarette nicotine withdrawal symptoms explain why people who smoke experience more daily stress than non-smokers, and become less stressed when they quit smoking. Deprivation reversal also explains much of the arousal data, with deprived smokers being less vigilant and less alert than non-deprived smokers or non-smokers. Recent studies have shown a positive relationship between psychological distress and salivary cotinine levels in smoking and non-smoking adults, indicating that both first-hand and second-hand smoke exposure may lead to higher levels of mental stress.
=== 27 April === A Moscow court fined the Wikimedia Foundation, the hosting platform for Wikipedia, two million roubles. This is the seventh fine since 2023 by a Russian court. The latest fine was for a failure to remove an article from Wikipedia that contains "classified military information" about the war in Ukraine. Russian digital affairs minister Maksut Shadaev told Interfax "We are not blocking Wikipedia yet, there are no such plans for now." Jens Stoltenberg, Secretary General of NATO, announced that since the start of the war NATO had provided Ukraine with anti-aircraft weapon systems, some MiG-29 aircraft, 230 tanks and 1550 other armored vehicles, which makes up 98% of the previously promised aid in armored vehicles. He said that NATO had trained enough Ukrainians to assemble 9 new armored brigades, which put Ukraine in a strong position to recapture occupied territories. Melitopol's chief of police, Oleksandr Mishchenko, was killed by an Improvised explosive device. He had been collaborating with the Russian forces since they captured the city. Another police officer was killed and one more wounded. The attack was blamed on Ukrainian partisans. It was reported that a military projectile had been discovered in a forest close to the village of Zamosc near Bydgoszcz, Poland. It was later identified as a Russian Kh-55 missile. According to Finnish Foreign Minister Pekka Haavisto, the Russian Central Bank had frozen the bank accounts of the Finnish Embassy in Moscow and the Finnish consulate in Saint Petersburg.
=== Antidote to heparin === Protamine sulfate has been given to counteract the anticoagulant effect of heparin (1 mg per 100 units of heparin that had been given over the past 6 hours). It may be used in those who overdose on heparin or to reverse heparin's effect when it is no longer needed.
==== Other ==== Many other Wildcats have met with success at the university. Alix Creek and Michelle Oldham won the NCAA Women's Doubles Tennis title in 1993, defeating Texas in the Final. Although surprising to some, the University of Arizona has a noteworthy history in ice hockey. The school's club hockey team, formerly known as the Icecats, won over 800 games between its inception in 1979 and 2011. The Ice Cats defeated Penn State for the National Collegiate Club Hockey National Championship in 1985. They also appeared in eight Final Fours ('84, '86, '87, '88, '91, '93, '94, '97) and ten Elite Eights. As of 2011, they are part of ACHA Division I, and are known formally as the Arizona Wildcats hockey team. Robert M. Tanita was a nationally ranked collegiate wrestler who reached the NCAA finals tournament as WAC champion in 1963. Three national championships for synchronized swimming were won in 1980, 1981, and 1984, though these championships were in the Association of Intercollegiate Athletics for Women, and not the NCAA. Along with winning three national championships in the pool for synchronized swimming, the Wildcats have also won their first NCAA Championship in men and women's swimming and diving for the seasons of 2007–2008. Topping off these weekends Frank Busch, the men and women's head coach, was named NCAA Swimming Coach of the Year. Arizona men became the first team to claim a first-time title since UCLA's win in 1982. Also, the men ended Texas and Auburn's winning streak since 1998.
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.
It is a synthetic tetrapeptide built from alanine, glutamate, aspartate and glycine. The four residues are joined by standard peptide bonds, giving a linear chain rather than a branched structure.