Telomerase raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-01-23. Anything still debated is marked as such rather than presented as settled.
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.
==== Gastrointestinal and colorectal cancer ==== Reviews of preliminary clinical trials on people with colorectal or gastrointestinal cancer suggest that soy isoflavones may have a slight protective effect against such cancers.
John James Rickard Macleod (6 September 1876 – 16 March 1935), was a Scottish biochemist and physiologist. He devoted his career to diverse topics in physiology and biochemistry, but was chiefly interested in carbohydrate metabolism. He is noted for his role in the discovery and isolation of insulin during his tenure as a lecturer at the University of Toronto, for which he and Frederick Banting received the 1923 Nobel prize in Physiology or Medicine. Awarding the prize to Macleod was controversial at the time, because according to Banting's version of events, Macleod's role in the discovery was negligible. It was not until decades after the events that an independent review acknowledged a far greater role than was attributed to him at first.
On 24 July 1967, shortly before midnight, President Lyndon B. Johnson ordered the US military to occupy Detroit. At 1:10 a.m., 4,700 paratroopers of the 82nd and 101st Airborne Divisions, under the command of Lieutenant General John L. Throckmorton, arrived in Detroit and began working in the streets, coordinating refuse removal, tracing persons who had disappeared in the confusion, and carrying out routine military functions, such as the establishment of mobile patrols, guard posts, and roadblocks. Rioting peaked in high intensity. The 82nd worked alongside the 101st to secure east of Woodward, while the National Guard took land west of Woodward. "Incidents" began to decline as paratroopers constantly patrolled the perimeter with M16 rifles, M60 machine guns, and M48 tanks, while the police began making arrests on those violating curfew regulations or who were caught looting. On 27 July, with a sense of normalcy returned to the city, in part due to the presence of Army and National Guard troops, and the riot was officially declared over. The Army began to scale down to return to their normal duties, relinquishing control to local authorities. Although Army paratroopers exercised some restraint on firepower due to being racially integrated, as well as their combat experience in Vietnam (as opposed to the mainly white and inexperienced National Guard troops), the 82nd was directly responsible for at least one death.
By early December 1984, most of the plant's MIC related safety systems were malfunctioning and many valves and lines were in poor condition. In addition, several vent gas scrubbers had been out of service, as well as the steam boiler intended to clean the pipes. During the late evening hours of 2 December 1984, water was believed to have entered tank E610 via a side pipe during attempts to unclog it. The tank still contained the 42 tons of MIC that had been there since late October. The introduction of water into the tank resulted in a runaway exothermic reaction, which was accelerated by contaminants, high ambient temperatures, and various other factors such as the presence of iron from corroding non-stainless steel pipelines. The pressure in tank E610, although initially nominal at 14 kilopascals (2 psi) at 10:30 p.m., reached 70 kilopascals (10 psi) as of 11 p.m. Two different senior refinery employees assumed the reading was instrumentation malfunction. By 11:30 p.m., workers in the MIC area were feeling the effects of minor exposure to MIC gas and began to look for a leak. One was found by 11:45 p.m. and reported to the MIC supervisor on duty at the time. The decision was made to address the problem after a 12:15 a.m. tea break, and in the meantime, employees were instructed to continue looking for leaks. The problem was discussed by MIC area employees during the break. When the tea break concluded at 12:40 a.m., the reaction in tank E610 escalated to a critical state at a rapid speed within five minutes.
==== Absorption ==== With oral administration of a single dose, THC is almost completely absorbed by the gastrointestinal tract. However, due to first-pass metabolism in the liver and the high lipid solubility of THC, only about 5 to 20% reaches circulation. Following oral administration, concentrations of THC and its major active metabolite 11-hydroxy-THC (11-OH-THC) peak after 0.5 to 4 hours, with median time to peak of 1.0 to 2.5 hours at different doses. In some cases, peak levels may not occur for as long as 6 hours. Concentrations of THC and 11-hydroxy-THC in the circulation are approximately equal with oral administration. There is a slight increase in dose proportionality in terms of peak and area-under-the-curve levels of THC with increasing oral doses over a range of 2.5 to 10 mg. A high-fat meal delays time to peak concentrations of oral THC by 4 hours on average and increases area-under-the-curve exposure by 2.9-fold, but peak concentrations are not significantly altered. A high-fat meal additionally increases absorption of THC via the lymphatic system and allows it to bypass first-pass metabolism. Consequently, a high-fat meal increases levels of 11-hydroxy-THC by only 25% and most of the increase in bioavailability is due to increased levels of THC. The bioavailability of THC when smoking or inhaling is approximately 25%, with a range of 2% to 56% (although most commonly between 10–35%).
Sources: en.wikipedia.org
Atomic nuclei consist of protons and neutrons bound together by the residual strong force. Because protons are positively charged, they repel each other. Neutrons, which are electrically neutral, stabilize the nucleus in two ways. Their copresence pushes protons slightly apart, reducing the electrostatic repulsion between the protons, and they exert an attractive nuclear force on each other and on protons. For this reason, one or more neutrons are necessary for two or more protons to bind into a nucleus. As the number of protons increases, so does the ratio of neutrons to protons necessary to ensure a stable nucleus (see graph at right). For example, although the neutron:proton ratio of 32He is 1:2, the neutron:proton ratio of 23892U is greater than 3:2. A number of lighter elements have stable nuclides with the ratio 1:1 (Z = N). The nuclide 4020Ca (calcium-40) is observationally the heaviest stable nuclide with the same number of neutrons and protons. All stable nuclides heavier than calcium-40 contain more neutrons than protons.
At first, common carrier was only limited to a small area around Los Angeles but by 1927 expanded to areas up to 125 miles outside the city. In 1924, a conveyor belt system was debuted for the handling of packages for UPS operations. In 1930, a consolidated carrier service began in New York City; soon after, the company expanded its services to include other major cities in the East and the Midwest. The use of a common carrier for delivery between all customers placed UPS in direct competition with USPS, and delivering parcels beyond the California border brought it under the jurisdiction of the Interstate Commerce Commission. The first city for UPS to use common carrier status outside California was Chicago, Illinois, in 1953.
== History == Prior to being domesticated, dogs, being canines, fended for themselves and survived on a carnivorous diet. After adapting them for protection, work, and companionship, people began to care at least in part for their nutritional needs. The historic record of this changing approach dates back at least 2,000 years. In 37 BCE, Virgil talks about the feeding of dogs in his Bucolics:
== June 4, 1915 (Friday) == Third Battle of Krithia — British, French, and Indian forces made a third and last attempt to capture Achi Baba, the main position for Ottoman defenses on the Gallipoli peninsula but were beaten back, sustaining some 6,500 casualties. Ottoman casualties were higher, ranging between 9,000 and 10,000 men. The LZ 40, the first Zeppelin P Class airship of the Imperial German Navy, was flown to bomb targets in London. The Royal Norwegian Navy Air Service test flew the M.F.1 floatplane in Horten, Norway, the first Marinens Flyvebaatfabrikk model based on a design by Maurice Farman. The fraternity Alpha Sigma Nu was founded at Marquette University as an honor society for Jesuit colleges. Born: Modibo Keïta, Malian statesman, first President of Mali; in Bamako Coura, French Sudan (present-day Bamako, Mali) (d. 1977) Walter Hadlee, New Zealand cricketer, batman for the New Zealand national cricket team from 1937 to 1951; in Lincoln, New Zealand (d. 2006)
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.