tetrapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-06-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
| 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 most frequently cited proposed action is induction of telomerase, the enzyme that adds repeat sequences to chromosome ends. Cell-culture work from the originating group reported higher telomerase reverse transcriptase expression and measurable telomere elongation in human somatic cells after exposure. How a four-residue peptide would reach nuclear gene regulation is not established, and no cell-surface receptor or uptake route has been identified. Additional reports describe changes in melatonin secretion, antioxidant enzyme activity and lipid peroxidation in aged animals, but these findings remain mechanistically unconnected to the telomerase observation.
Published evidence comes mainly from Russian-language journals and from a single research group, with small sample sizes and limited independent replication. A few laboratories outside that group have examined related peptides and reported weaker or absent telomerase effects, so the central claim is best described as contested rather than settled. Rodent studies report modest changes in some ageing markers and in survival, but designs vary and control conditions are often sparse. No large randomised trial in humans has been published, and long-term safety data in healthy populations are correspondingly thin.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
== External links == Biological Products at the U.S. National Library of Medicine Medical Subject Headings (MeSH) Debbie Strickland (2007). "Guide to Biotechnology" (PDF). Biotechnology Industry Organization (BIO). Archived from the original (PDF) on 2007-09-27. Retrieved 2007-12-17. Timothy B. Coan; Ron Ellis (2001-06-01). "Report for USA Specialty Pharmaceuticals: Generic Biologics: The Next Frontier" (PDF). Consumer Project on Technology. Retrieved 2007-12-17. "About biologics". National Psoriasis Foundation. 2006-11-01. Archived from the original on 2006-01-01. Retrieved 2007-12-17.
Adjustments to the manufacturing process can affect thickness, panel size, strength, and rigidity. OSB panels have no internal gaps or voids, and can be water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use. The finished product has properties similar to plywood, but is uniform and cheaper. When tested to failure, OSB has a greater load-bearing capacity than milled wood panels. It has replaced plywood in many environments, especially the North American structural panel market. All wood-based structural use panels can be cut and installed with the same types of equipment as for solid wood.
This increased demand is met by an increase in the stroke volume of the octopus' heart. The octopus does sometimes swim throughout the water, exposing itself completely. In doing so, it uses a jet mechanism that involves creating a much higher pressure in its mantle cavity that allows it to propel itself through the water. As the common octopus' heart and gills are located within its mantle, this high pressure also constricts and puts constraints on the various vessels that are returning blood to the heart. Ultimately, this creates circulation issues and is not a sustainable form of transportation, as the octopus cannot attain an oxygen intake that can balance the metabolic demands of maximum exertion.
When the USSR was dissolved in 1991, Moscow remained the capital of the Russian Federation. Since then, a market economy has emerged, producing a significant increase in Western-style retailing, services, architecture, and lifestyles. The city continued to grow during the 1990s and 2000s, its population rising from less than nine million to more than ten million. Scholars Mason and Nigmatullina argue that Soviet-era urban-growth controls produced controlled and sustainable metropolitan development, typified by the greenbelt built in 1935. Since then, however, low-density suburban sprawl has increased significantly, as a result of heavy demand for single-family dwellings (rather than multi-family apartments). In 1995–1997, the MKAD ring road was widened from an initial four lanes to ten lanes. In December 2002, Bulvar Dmitriya Donskogo became the first Moscow Metro station to open outside the MKAD. The Third Ring Road—intermediate between the early 19th-century Garden Ring and the Soviet-era outer ring road—was completed in 2004. The greenbelt is becoming more fragmented, and satellite cities are appearing at the fringe. Summer dachas are being converted into year-round residences; with the proliferation of automobiles, the city has heavy traffic congestion. Multiple old churches and other examples of architectural heritage that were demolished during the Stalin era have been restored, such as the Cathedral of Christ the Saviour. In the 2010s, Moscow's administration launched long-term projects such as the Moja Ulitsa (lit.
== Research and career == Franz became an assistant professor at Duke University in 2003. She is an Associate member of the Duke Cancer Institute. In 2005, Franz was awarded an National Science Foundation CAREER Award. She was made a Sloan Research Fellow in 2008 and promoted to professor in 2015. Franz has investigated the use of cellular metals in antimicrobial resistance. For example, by disrupting the amount of iron in a cell it is possible to withhold an essential pathogen, limiting the growth of microbes. On the other hand, copper can be used to control the growth of microbes, and immune cells appear to move copper to kill pathogens. At the same time, pathogens try to use copper to enhance their resistance and likelihood of survival. Franz attempts to use copper in the same way as biological systems to target antimicrobial agents. She has looked at iron and copper as ionophores; which are important in the virulence of Cryptococcus neoformans. Franz also works on anti-cancer prochelators; molecules that do not have much affinity for metal ions, but can be triggered until they undergo a chemical conversion. Cancer cells have different metallomes than normal cells. For example, prostate cancer results in the overexpression of copper trafficking proteins, causing a high level of copper. She looks to target these copper ions by creating prochelators that become activated in the microenvironment of cancer.
Sources: en.wikipedia.org
However, creatine kinase-MB isoform and myoglobin levels circulating in the blood are increased after exercising. Excessive cooling may impede the recovery process by keeping the Creatine kinase-MB isoform and myoglobin levels increased 2–3 days post exercise. When possible, the affected limb is elevated above the level of the heart, and is compressed using adhesive tape. Evidence supporting elevation and compression is weak, but continues to be widely practiced.
Multipolar neurons: Have 3 or more processes coming off the soma (cell body). They are the major neuron type in the CNS and include interneurons and motor neurons. Bipolar neurons: Sensory neurons that have two processes coming off the soma, one dendrite and one axon Pseudounipolar neurons: Sensory neurons that have one process that splits into two branches, forming the axon and dendrite Unipolar brush cells: Are excitatory glutamatergic interneurons that have a single short dendrite terminating in a brush-like tuft of dendrioles. These are found in the granular layer of the cerebellum. Neuroglia encompasses the non-neural cells in nervous tissue that provide various crucial supportive functions for neurons. They are smaller than neurons, and vary in structure according to their function. Neuroglial cells are classified as follows:
And it created a Carbon Mitigation Credit, funded by a surcharge added to energy bills, to subsidize the operation of nuclear power plants during times when they would ordinarily be unprofitable. The law also requires nuclear power plant operators to send a credit back to ratepayers when demand for nuclear energy, and by extension energy rates, rise, which has given ratepayers a partial break on their monthly payments at various times since the law passed.
=== Classical philosophy === When the word "anarchy" (Greek: αναρχία, romanized: anarchia) was first defined in ancient Greece, it initially had both a positive and negative connotation, respectively referring to spontaneous order or chaos without rulers. The latter definition was taken by the philosopher Plato, who criticised Athenian democracy as "anarchical", and his disciple Aristotle, who questioned how to prevent democracy from descending into anarchy. Ancient Greek philosophy initially understood anarchy to be a corrupted form of direct democracy, although it later came to be conceived of as its own form of political regime, distinct from any kind of democracy. According to the traditional conception of political regimes, anarchy results when authority is derived from a majority of people who pursue their own interests.
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.
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.