If you have been reading about Telomerase and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-03-18. Numbers and descriptions here follow the published literature rather than marketing material.
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 four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
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.
Human data are limited to small studies, often without the randomization, blinding, or control groups expected in contemporary clinical research. Reported outcomes have included changes in melatonin levels, immune markers, and subjective measures, but sample sizes were generally too small to support firm conclusions. Some reviews treat the peptide as promising while noting methodological weaknesses; others question whether the observed effects are specific. The compound is frequently discussed in longevity-focused communities, where enthusiasm often outpaces the published evidence. Separating established findings from speculation is therefore important when reading summaries of this research.
Epitalon emerged from research conducted in Saint Petersburg by Vladimir Khavinson and colleagues, who studied short peptides as potential regulators of aging. The work built on epithalamin, a pineal gland extract reported to influence neuroendocrine function. Epitalon was designed as a synthetic counterpart with a defined sequence, allowing reproducible experiments that extracts could not support. Early publications described effects on melatonin rhythms and lifespan in animal models. These findings circulated mainly in Russian-language journals during the 1990s, which limited their visibility among English-speaking researchers.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
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.
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.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
== Stages of progress in nanotechnology == In 2005, Mihail Roco, one of the architects of the USA's National Nanotechnology Initiative, proposed four states of nanotechnology that seem to parallel the technical progress of the Industrial Revolution, of which productive nanosystems is the most advanced. 1. Passive nanostructures - nanoparticles and nanotubes that provide added strength, electrical and thermal conductivity, toughness, hydrophilic/phobic and/or other properties that emerge from their nanoscale structure. 2. Active nanodevices - nanostructures that change states in order to transform energy, information, and/or to perform useful functions. There is some debate about whether or not state-of-the art integrated circuits qualify here, since they operate despite emergent nanoscale properties, not because of them. Therefore, the argument goes, they don't qualify as "novel" nanoscale properties, even though the devices themselves are between one and a hundred nanometers. 3. Complex nanomachines - the assembly of different nanodevices into a nanosystem to accomplish a complex function. Some would argue that Zettl's machines fit in this category; others argue that modern microprocessors and FPGAs also fit. 4. Systems of nanosystems/Productive nanosystems - these will be complex nanosystems that produce atomically precise parts for other nanosystems, not necessarily using novel nanoscale-emergent properties, but well-understood fundamentals of manufacturing. Because of the discrete (i.e.
Colombia has free-trade zones (FTZ), such as Zona Franca del Pacifico, located in the Valle del Cauca, one of the most striking areas for foreign investment. The financial sector has grown favorably due to good liquidity in the economy, the growth of credit and the positive performance of the Colombian economy. The Colombian Stock Exchange through the Latin American Integrated Market (MILA) offers a regional market to trade equities. Colombia is now one of only three economies with a perfect score on the strength of legal rights index, according to the World Bank. Colombia is rich in natural resources, and it is heavily dependent on energy and mining exports. Colombia's main exports include mineral fuels, oils, distillation products, fruit and other agricultural products, sugars and sugar confectionery, food products, plastics, precious stones, metals, forest products, chemical goods, pharmaceuticals, vehicles, electronic products, electrical equipment, perfumery and cosmetics, machinery, manufactured articles, textile and fabrics, clothing and footwear, glass and glassware, furniture, prefabricated buildings, military products, home and office material, construction equipment, software, among others. Principal trading partners are the United States, China, the European Union and some Latin American countries. Non-traditional exports have boosted the growth of Colombian foreign sales as well as the diversification of destinations of export thanks to new free trade agreements.
Therefore, most of the silver found in wastewater treatment plants is in the form of silver nanoparticles or silver precipitates such as Ag2S and AgCl. The amount of silver precipitate formed depends on silver ion release, which increases with increasing dissolved oxygen concentration and decreasing pH. Silver ions account for approximately 1% of total silver after silver nanoparticles are suspended in aerated water. In anoxic wastewater treatment environments, silver ion release is therefore often negligible, and most of the silver nanoparticles in wastewater remain in the original silver nanoparticle form. The presence of natural organic matter can also decrease oxidative dissolution rates and therefore the release rate of free silver ions. The slow oxidation of silver nanoparticles may enable new pathways for its transfer into the environment.
=== Plot === An unnamed character, only referred as "Candidate Twelve," arrives for work at the Black Mesa Research Facility. The facility has flickering of lights and failing electrical equipment, with tremors shaking it as scientists begin to worry about the experiment. After entering a tram, the "resonance cascade" forces Candidate Twelve to fight for survival as the G-Man observes. After the resonance cascade, Candidate Twelve battles through the facility's sewer system, encountering other survivors along the way. The gargantua, a massive alien organism, stalks the player's movements. The player eventually escapes to the surface in a large freight elevator. After taking it, Candidate Twelve meets a construction worker that has a plan to escape. He sends off Candidate Twelve to look for a security guard needed for a door he's stuck behind. At this time, military convoys can be seen entering Black Mesa. The player nearly escapes with the construction worker, a surviving security guard and scientist, but the construction worker turns out to be dead, impaled by crossbow arrows. The rest are ambushed by the HECU marines and killed. Candidate Twelve escapes and battles the military en route back to the transit hub from the start of the game. Along the way, Candidate Twelve encounters visions projected by a sentient entity that grants visions of the Universal Union, also known as the Combine. The entity appears to be fleeing the powers of the enigmatic G-Man. Candidate Twelve arrives at a climactic confrontation between the Xen aliens and the HECU marines.
== Discovery and structure == In 1991 a research group led by Clarence A. Ryan, isolated an 18 amino acid polypeptide from tomato leaves that induced the production of protease inhibitor proteins (PIs) in response to wounding. Experiments using synthetic radio-labelled forms of the polypeptide demonstrated that it was able to travel systemically through the plant and induce PI production in unwounded leaves. Because of the systemic nature of the wounding signal, it was named systemin, it was the first polypeptide found to function as a hormone in plants. mRNA encoding for systemin is found in all tissues of the plant except the roots. Later studies identified homologs of tomato systemin in other members of the Solanaceae including potato, black nightshade and bell pepper. Systemins have only been identified in the Solaneae subtribe of the Solanaceae, but other members of the family, such as tobacco, also respond to wounding by systemically producing protease inhibitors.
Sources: en.wikipedia.org
== Early life and education == Otto Hahn was born in Frankfurt am Main on 8 March 1879, the youngest son of Heinrich Hahn, a prosperous glazier and founder of the Glasbau Hahn company, and Charlotte Hahn (née Giese). He had an older half-brother Karl, his mother's son from her previous marriage, and two older brothers, Heiner and Julius. The family lived above his father's workshop. The younger three boys were educated at the Klinger Oberrealschule in Frankfurt. At the age of 15, Otto began to take a special interest in chemistry, and carried out simple experiments in the laundry room of the family home. His father wanted him to study architecture, as he had built or acquired several residential and business properties, but Otto persuaded him that his ambition was to become an industrial chemist. In 1897, after passing his Abitur, Hahn began to study chemistry at Marburg University. His subsidiary subjects were mathematics, physics, mineralogy and philosophy. Hahn joined the Students' Association of Natural Sciences and Medicine, a student fraternity and a forerunner of today's Landsmannschaft Nibelungi (Coburger Convent der akademischen Landsmannschaften und Turnerschaften). He spent his third and fourth semesters at the Ludwig-Maximilians-Universität München, studying organic chemistry under Adolf von Baeyer, physical chemistry under Wilhelm Muthmann, and inorganic chemistry under Karl Andreas Hofmann. In 1901, Hahn received his doctorate at Marburg University for a dissertation entitled "On Bromine Derivates of Isoeugenol", a topic in classical organic chemistry.
Movement demands include strength, endurance and range of motion. Training oversights occurs when the body is overused. Internally, the joints, muscles, tendons, and ligaments can affect one's flexibility. As previously mentioned, each part of the body has its own limitations and combined, the range of motion can be affected. The mental attitude of the performer during the state of motion can also affect their range.
Sports nutrition is the study and practice of nutrition and diet for maintaining and improving athletic performance. Nutrition is part of many sports training regimens, being used in strength sports (such as weightlifting and bodybuilding) and endurance sports (e.g., cycling, running, swimming, rowing). Sports nutrition focuses on the type, as well as the quantity, of fluids and food taken by an athlete. It deals with consuming nutrients, such as vitamins, minerals, carbohydrates, proteins, and fats.
Since October 1, 2007, it has been illegal for retailers to sell tobacco in all forms to people under the age of 18 in three of the UK's four constituent countries (England, Wales, Northern Ireland, and Scotland), increased from 16. It is also illegal to sell lighters, rolling papers, and all other tobacco-associated items to people under 18. It is not illegal for people under 18 to buy or smoke tobacco, it is only illegal for a retailer to sell a tobacco-associated item to them. The age increase from 16 to 18 came into force in Northern Ireland on September 1, 2008. In the Republic of Ireland, bans on the sale of smaller 10-packs and confectionery that resembles tobacco products (candy cigarettes) came into force on May 31, 2007, in a bid to cut underaged smoking. In October 2023, Prime Minister Rishi Sunak proposed a ban on sales of cigarettes to anyone born after 2008. Most countries in the world have a legal vending age of 18. In North Macedonia, Italy, Malta, Austria, Luxembourg, and Belgium, the age for legal vending is 16. Since January 1, 2007, all cigarette machines in public places in Germany must attempt to verify a customer's age by requiring the insertion of a debit card. Turkey, which has one of the highest percentages of smokers by population, has a legal age of 18. Japan is one of the highest tobacco-consuming nations, and requires purchasers to be 20 years of age. Since July 2008, Japan has enforced this age limit at cigarette vending machines through use of the Taspo smart card.
Sources: en.wikipedia.org
=== Media === The most influential newspapers in the country were the Rhodesia Herald in Salisbury and The Chronicle in Bulawayo. Following UDI, in 1976, the state-run Rhodesian Broadcasting Corporation (RBC) took over the privately owned Rhodesia Television (RTV) service, in which it had previously acquired a 51 percent stake. Among the news magazines published in Rhodesia under UDI were the Illustrated Life Rhodesia, while The Valiant Years by Beryl Salt told the history of Rhodesia from 1890 to 1978 entirely through the medium of facsimile reproduction of articles and headlines from Rhodesian newspapers.
The melting and boiling points of iron, along with its enthalpy of atomization, are lower than those of the earlier 3d elements from scandium to chromium, showing the lessened contribution of the 3d electrons to metallic bonding as they are attracted more and more into the inert core by the nucleus; however, they are higher than the values for the previous element manganese because that element has a half-filled 3d sub-shell and consequently its d-electrons are not easily delocalized. This same trend appears for ruthenium but not osmium. The melting point of iron is experimentally well defined for pressures less than 50 GPa. For greater pressures, published data (as of 2007) still varies by tens of gigapascals and over a thousand kelvin.
== Surrogate endpoint == A surrogate endpoint (or marker) is a measure of effect of a specific treatment that may correlate with a real clinical endpoint but doesn't necessarily have a guaranteed relationship. The National Institutes of Health (USA) define surrogate endpoint as "a biomarker intended to substitute for a clinical endpoint".
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
Vladimir Khavinson and colleagues at research institutes in Saint Petersburg developed and studied the peptide. Their program examined short peptides as regulators of aging and neuroendocrine function. Epitalon was one of several compounds produced by that group.