The short version of tetrapeptide fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-15. 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.
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.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
Regulatory status varies by country and is not harmonized. Epitalon is not an approved drug in major Western jurisdictions. In some countries it is sold as a research chemical, and in others it has appeared in products marketed for other categories. This inconsistent status means that purity, labeling accuracy, and documentation differ widely between suppliers, and verification of identity and purity through independent analysis is the usual way buyers assess a given lot.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
| 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 |
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
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.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
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 sequence alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. Its design traces to epithalamin, a peptide fraction prepared from bovine pineal gland extracts that researchers in Saint Petersburg began investigating in the 1970s. The compound has a molecular formula of C14H22N4O9 and a nominal molecular mass near 390 daltons. It holds no approved drug status in the United States or the European Union, and material sold under this name is generally offered as a research chemical rather than a finished pharmaceutical product.
== See also == D-peptide – Class of amino acids Mirror matter – A hypothetical form of matter that interacts only weakly with normal matter, which could form mirror planets, potentially inhabited by mirror-matter life Shadow biosphere – Hypothetical biosphere of Earth Xenobiology – Science of synthetic life forms
== The proteome in bacterial systems == Proteomic analyses have been performed in different kinds of bacteria to assess their metabolic reactions to different conditions. For example, in bacteria such as Clostridium and Bacillus, proteomic analyses were used in order to investigate how different proteins help each of these bacteria spores germinate after a prolonged period of dormancy. In order to better understand how to properly eliminate spores, proteomic analysis must be performed.
Most reptiles, as well as birds, possess a nictitating membrane, a translucent third eyelid which is drawn over the eye from the inner corner. In crocodilians, it protects its eyeball surface while allowing a degree of vision underwater. However, many squamates, geckos and snakes in particular, lack eyelids, which are replaced by a transparent scale. This is called the brille, spectacle, or eyecap. The brille is usually not visible, except for when the snake molts, and it protects the eyes from dust and dirt.
Banting also maintained this position in his report to the Department of the Interior:He noted that "infant mortality was high because of the undernourishment of the mother before birth"; that "white man's food leads to decay of native teeth"; that "tuberculosis has commenced. Saw several cases at Godhavn, Etah, Port Burwell, Arctic Bay"; that "an epidemic resembling influenza killed a considerable proportion of population at Port Burwell"; and that "the gravest danger faces the Eskimo in his transfer from a race-long hunter to a dependent trapper. White flour, sea-biscuits, tea and tobacco do not provide sufficient fuel to warm and nourish him." Furthermore, he discouraged the establishment of an Arctic hospital. The "proposed hospital at Pangnirtung would be a waste of money, as it could be reached by only a few natives." Banting's report contrasted starkly with the bland descriptions provided by the ship's physician, F. H. Stringer.
=== Essendon === Thompson played for Essendon Football Club from 1983 until 1996, playing a total number of 202 games and kicked a total of 50 goals. Thompson played most of his football in the backline, gaining a reputation as a fierce competitor. He won the club award for "Most Determined Player" in 1984 and 1986, "Most Improved Player" and "Best Clubman" in 1985, and best-and-fairest awards in 1987 and 1990. He also finished in the top five in the best-and-fairest on four other occasions. Thompson played in the 1984 and 1985 premiership sides and captained the 1993 premiership team. In 2002, Thompson's contribution to the club was recognised when he was voted the 20th best Essendon player of all time in the "Champions of Essendon" list.
Sources: en.wikipedia.org
Some glycerol-based ear medications for use in removing excess wax as well as relieving ear conditions such as otitis media and swimmer's ear. Some previous diet products such as Ayds. Some condoms designed to prevent premature ejaculation. Benzocaine largely inhibits sensitivity on the penis, and can allow for an erection to be maintained longer (in a continuous act) by delaying ejaculation. Conversely, an erection will also fade faster if stimulus is interrupted. Benzocaine mucoadhesive patches have been used in reducing orthodontic pain. In Poland it is included, together with menthol and zinc oxide, in the liquid powder (not to be confused with the liquid face powder) used mainly after mosquito bites. Today's ready-made Pudroderm was once used there as pharmaceutical compound.
=== 1964 === January 12: the Arab-dominated government of the Zanzibar Sultanate is overthrown by John Okello, establishing the new people's republic. The new regime orders a massacre against minorities, resulting in the deaths of hundred to thousand Arabs and South Asians in Zanzibar. January 27: France recognizes the People's Republic of China. The Republic of China severs diplomatic relations with France on February 10. March 31–April 1: A military-led coup d'état overthrows president João Goulart in Brazil. Goulart's proposals, such as land reform and bigger control of the state in the economy, were seen as communist. April 20: U.S. President Lyndon Johnson in New York, and Soviet First Secretary Nikita Khrushchev in Moscow, announce simultaneously plans to cut back production of materials for making nuclear weapons. May 27: Jawaharlal Nehru dies. The Colombian conflict begins. July 4: The Rhodesian Bush War begins when African nationalist / Marxist insurgents rebel against colonial rule in Rhodesia (modern-day Zimbabwe). Nyasaland (renamed Malawi upon independence) becomes independent from the UK. August 4: U.S. President Lyndon B. Johnson claims that North Vietnamese naval vessels had fired on two American destroyers in the Gulf of Tonkin. Although there was a first attack, it was later shown that American vessels had entered North Vietnamese territory first, and that the claim of second attack had been unfounded. The Gulf of Tonkin incident leads to the open involvement of the United States in the Vietnam War, after the Gulf of Tonkin Resolution.
=== Polonnaruwa === On 29 December 2012 a green fireball was observed in Polonnaruwa, Sri Lanka. It disintegrated into fragments that fell to the Earth near the villages of Aralaganwila and Dimbulagala and in a rice field near Dalukkane. Rock samples were submitted to the Medical Research Institute of the Ministry of Health in Colombo. The rocks were sent to the University of Cardiff in Wales for analysis, where Chandra Wickramasinghe's team analyzed them and claimed that they contained extraterrestrial diatoms. From January to March 2013, five papers were published in the fringe Journal of Cosmology outlining various results from teams in the United Kingdom, United States and Germany. However, independent experts in meteoritics stated that the object analyzed by Wickramasinghe's team was of terrestrial origin, a fulgurite created by lightning strikes on Earth. Experts in diatoms complemented the statement, saying that the organisms found in the rock represented a wide range of extant terrestrial taxa, confirming their earthly origin. Wickramasinghe and collaborators responded, using X-ray diffraction, oxygen isotope analysis, and scanning electron microscope observations, in a March 2013 paper asserting that the rocks they found were indeed meteorites, instead of being created by lightning strikes on Earth as stated by scientists from the University of Peradeniya. However, these claims were also criticised for not providing evidence that the rocks were actually meteorites.
The jury acquitted Letby of the attempted murder on counts 9 (Baby G) and 10 (Baby H), and was unable to reach verdicts on counts 11 (Baby H), 13 (Baby J), 14, (Baby K), 18 and 19 (Baby N), and 22 (Baby Q). On 21 August 2023, Letby was sentenced to life imprisonment with a whole life order, the most severe penalty available under English law. She became the fourth woman in the UK to receive such a sentence. In his remarks, Goss described her actions as "a cruel, calculated and cynical campaign of child murder involving the smallest and most vulnerable of children", adding that "there was a deep malevolence bordering on sadism [...] you [Letby] have no remorse [...] there are no mitigating factors [...] the offences are of sufficient severity to require a whole life order." Letby chose not to attend the sentencing hearing and therefore did not hear the victim impact statements or the sentence being passed. In response, the Secretary of State for Justice, Alex Chalk, said the government would "look at options to change the law at the earliest opportunity" to require defendants to attend their sentencing. Following the trial, Letby was transferred to HMP Low Newton in County Durham. As of February 2025, she is held at HM Prison Bronzefield.
Sources: en.wikipedia.org
== Waitrose effect == Proximity to a supermarket has been widely reported to be an amenity that can have a significant effect on residential property prices in Britain. Beginning under Andy Hulme and continuing under Mike Songer, the home mortgage unit of Lloyds Bank has published pricing research that examines the premiums commanded by homes in a given neighbourhood against comparables in the same post-code and correlates the difference in price with convenience of access to the various supermarkets. The following table averages information from neighbourhoods across England and Wales, compiled by Lloyds Bank for its 2016 report using supermarket location information from CACI Datalab and house price information from HM Land Registry.
== Measurement == Follicle-stimulating hormone is typically measured in the early follicular phase of the menstrual cycle, typically day three to five, counted from last menstruation. At this time, the levels of estradiol (E2) and progesterone are at the lowest point of the menstrual cycle. FSH levels in this time is often called basal FSH levels, to distinguish from the increased levels when approaching ovulation. FSH is measured in international units (IU). For Human Urinary FSH, one IU is defined as the amount of FSH that has an activity corresponding to 0.11388 mg of pure Human Urinary FSH. For recombinant FSH, one IU corresponds to approximately 0.065 to 0.075 μg of a "fill-by-mass" product. The mean values for women before ovulation are around (3.8-8.8) IU/L. After ovulation these levels drop to between (1.8-5.1) IU/L. At the mid of the menstrual cycle it reaches its highest value, between (4.5-22.5) IU/L. During menopause, the values goes up even more, between (16.74-113.59) IU/L. For men, the mean values are around (1.5-12.4) IU/L.
=== Vedolizumab === Vedolizumab is very similar to natalizumab in that it is a humanized IgG monoclonal antibody, but vedolizumab is an IgG1 that specifically blocks the alpha 4 beta 7 integrin that is located primarily on cells in the gastrointestinal tract. It is promoted as being gut specific due to the localization of alpha 4 beta 7 integrin in the gastrointestinal tract and was the first biologic to be made specifically for inflammatory bowel disease.
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.
Identity is normally confirmed by mass spectrometry, which checks the measured mass against the expected value near 390 daltons. Reverse-phase high-performance liquid chromatography is used alongside it to assess purity. Amino acid analysis can provide additional composition data.