A practical reference on tetrapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-08-15 and is reviewed periodically as new material appears.
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.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
（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.
Most experimental work has been carried out in cell culture and animal models. Several reports describe changes in telomerase activity and proliferation in cultured cells, while rodent studies have examined lifespan, melatonin rhythm and reproductive endpoints. Human data remain limited, and much of the published clinical material consists of small trials with incomplete reporting of methods and controls. Whether the cell and animal findings translate into measurable effects in people is an open question, and the mechanistic basis of the reported telomerase changes is not fully established.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
=== Accumulation in buildings === Measurement of radon levels in the first decades of its discovery was mainly done to determine the presence of radium and uranium in geological surveys. In 1956, most likely the first indoor survey of radon decay products was performed in Sweden, with the intent of estimating the public exposure to radon and its decay products. From 1975 up until 1984, small studies in Sweden, Austria, the United States and Norway aimed to measure radon indoors and in metropolitan areas.
Summarising their findings, they conclude: "The medical notes indicate that, on admission, Dylan's bronchial disease was found to be very extensive, affecting upper, mid and lower lung fields, both left and right." The forensic pathologist, Bernard Knight, who examined the post-mortem report, concurs: "death was clearly due to a severe lung infection with extensive advanced bronchopneumonia...the severity of the chest infection, with greyish consolidated areas of well-established pneumonia, suggests that it had started before admission to hospital." Thomas died at noon on 9 November 1953, having never recovered from his coma. A nurse, and the poet John Berryman, were present with him at the time of death.
The latter had expelled the Umayyads from the Hejaz and among the exiles to Syria was Marwan ibn al-Hakam, an Umayyad elder. Ubayd Allah persuaded Marwan, who was preparing to recognize Ibn al-Zubayr's sovereignty, to enter his candidacy as Mu'awiya II's successor. The Umayyads' principal Syrian allies, the Banu Kalb, had sought to maintain Umayyad rule and nominated Mu'awiya II's half-brother Khalid as caliph. However, the other pro-Umayyad Syrian tribes viewed Khalid as too young and inexperienced, and rallied around Marwan, who was ultimately chosen as caliph.
Sources: en.wikipedia.org
X-rays of the hands and feet are generally performed when many joints are affected. In RA, there may be no changes in the early stages of the disease, or the X-ray may show osteopenia near the joint, soft tissue swelling, and a smaller than normal joint space. As the disease advances, there may be bony erosions and subluxation. Other medical imaging techniques such as magnetic resonance imaging (MRI) and ultrasound are also used in RA. Technical advances in ultrasonography, like high-frequency transducers (10 MHz or higher), have improved the spatial resolution of ultrasound images, depicting 20% more erosions than conventional radiography. Color Doppler and power Doppler ultrasound are useful in assessing the degree of synovial inflammation as they can show vascular signals of active synovitis. This is important since in the early stages of RA, the synovium is primarily affected, and synovitis seems to be the best predictive marker of future joint damage.
Melamine is mainly used in the chemical industry, but it can also be used in making cakes." Shandong Mingshui Great Chemical Group, the company reported by the New York Times as producing melamine from coal, produces and sells both urea and melamine but does not list melamine resin as a product. Another recall incident in 2007 involved melamine which had been purposely added as a binder to fish and livestock feed manufactured in the United States. This was traced to suppliers in Ohio and Colorado.
== Organs and tissues affected by IGF-1 == Since many distinct tissue types express the IGF-1 receptor, IGF-1's effects are diverse. It acts as a neurotrophic factor, inducing the survival of neurons. It may catalyse skeletal muscle hypertrophy, by inducing protein synthesis, and by blocking muscle atrophy. It is protective for cartilage cells, and is associated with activation of osteocytes, and thus may be an anabolic factor for bone. Since at high concentrations it is capable of activating the insulin receptor, it can also complement for the effects of insulin. Receptors for IGF-1 are found in vascular smooth muscle, while typical receptors for insulin are not found in vascular smooth muscle.
Sources: en.wikipedia.org
== History == The term "narcotic" is believed to have been coined by the Greek physician Galen to refer to agents that numb or deaden, causing paralysis or loss of feeling. It is based on the Greek word ναρκωσις (narcosis), the term used by Hippocrates for the process of numbing or the numbed state. Galen listed mandrake root, altercus (eclata), seeds, and poppy juice (opium) as the chief examples. It originally referred to any substance that relieved pain, dulled the senses, or induced sleep. Now, the term is used in many ways. Some people might define narcotics as substances that bind at opioid receptors (cellular membrane proteins activated by substances like heroin or morphine), while others refer to any illicit substance as a narcotic. From a U.S. legal perspective, narcotics refer to opium, opium derivatives, and their semi-synthetic substitutes, though in U.S. law, due to its numbing properties, cocaine is also considered a narcotic. The definition encompassing "any illegal drug" was first recorded in 1926. Its first use as an adjective is first attested to c. 1600. There are many different types of narcotics. The two most common forms of narcotic drugs are morphine and codeine. Both are synthesized from opium for medicinal use. The most commonly used drug for recreational purposes created from opium is heroin. Synthesized drugs created with an opium base for use in pain management are fentanyl, oxycodone, tramadol, pethidine (Demerol), hydrocodone, methadone, and hydromorphone. New forms of existing pain medications are being created regularly.
== Further reading == The immunological basis for immunization series: Module 10: Varicella-zoster virus. World Health Organization (WHO). May 2008. hdl:10665/43906. ISBN 978-92-4-159677-0. Ramsay M, ed. (March 2013). "Chapter 34: Varicella". Immunisation against infectious disease. Public Health England. Hall E, Wodi AP, Hamborsky J, Morelli V, Schillie S, eds. (2021). "Chapter 22: Varicella". Epidemiology and Prevention of Vaccine-Preventable Diseases (14th ed.). Washington D.C.: U.S. Centers for Disease Control and Prevention (CDC).` Roush SW, Baldy LM, Hall MA, eds. (9 January 2020). "Chapter 17: Varicella". Manual for the surveillance of vaccine-preventable diseases. Atlanta GA: Centers for Disease Control and Prevention (CDC).
BioShock received highly positive reviews from critics, with an average review score of 96/100 for Xbox 360 and Microsoft Windows, and 94/100 for PlayStation 3 on reviews aggregator Metacritic. Mainstream press reviews praised the immersive qualities of the game and its political dimension. The Boston Globe described it as "a beautiful, brutal, and disquieting computer game ... one of the best in years", and compared the game to Whittaker Chambers' 1957 riposte to Atlas Shrugged, "Big Sister Is Watching You". Wired also mentioned the Ayn Rand connection (a partial anagram of Andrew Ryan) in a report on the game which featured a brief interview with Levine. The Chicago Sun-Times review said "I never once thought anyone would be able to create an engaging and entertaining video game around the fiction and philosophy of Ayn Rand, but that is essentially what 2K Games has done ... the rare, mature video game that succeeds in making you think while you play". The Los Angeles Times review concluded: "Sure, it's fun to play, looks spectacular and is easy to control.
Sources: en.wikipedia.org
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.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.