If you have been reading about lyophilised powder 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 2026-01-19. Numbers and descriptions here follow the published literature rather than marketing material.
Regulatory treatment differs by country. No formulation of epitalon holds a marketing authorisation as a medicine in the United States or the European Union, where material sold for laboratory use is handled as a research chemical and is not intended for human consumption. In Russia, several short peptide preparations from the same institute's peptide series are registered medicinal products, and epitalon appears in that national context. Elsewhere it is frequently offered as a cosmetic ingredient, a category with lighter requirements. Advertising claims about longevity or disease prevention are restricted in most jurisdictions, which limits how sellers describe the compound.
Freeze-dried epitalon is normally kept at minus twenty degrees Celsius in a sealed, desiccated container, protected from light. Short excursions at ambient temperature during shipping are generally tolerated, but repeated warming and cooling cycles encourage moisture uptake, which shortens shelf life. Once dissolved, the peptide is far less stable than the solid: aqueous solutions are subject to hydrolysis and to deamidation at the aspartate and glutamate residues. Working solutions are therefore held refrigerated and used within days, and repeated freezing and thawing of the same vial is best avoided.
Identity and purity are checked by reversed-phase high-performance liquid chromatography, usually with ultraviolet detection near 214 nanometres, where the peptide bond absorbs. Mass spectrometry confirms the expected mass and reveals whether truncation products or adducts are present. Acid hydrolysis followed by amino acid analysis gives the residue ratio, which should approximate one alanine, one glutamate, one aspartate and one glycine. Counter-ions such as acetate or trifluoroacetate remain in the dried product and lower net peptide content, so a stated purity figure on a label does not by itself describe how much peptide a vial holds.
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 |
|---|---|---|
| Storage temperature, solid | Approximately -20 C | Sealed, desiccated, protected from light |
| Typical identity method | Electrospray mass spectrometry | Protonated ion expected near 391 |
| Typical purity method | Reversed-phase HPLC | Ultraviolet detection near 214 nm |
| Common synonyms | Epithalon, epithalone, AEDG | Spelling variants appear in supplier catalogues |
| Solution stability | Days at 2-8 C | Hydrolysis and deamidation limit shelf life |
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
Lyophilised epitalon is generally held at minus twenty degrees Celsius in a sealed container kept dry and dark. Cooler conditions are sometimes recommended for long-term archives. The solid takes up moisture readily enough that repeated opening of a vial introduces water, so dividing a batch into smaller portions before storage lowers degradation risk. Aqueous solutions are less durable than the dry powder and are usually prepared shortly before use, then kept cold and shielded from light to slow hydrolysis and oxidation.
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.
FARC dissidents are a group formerly part of the Revolutionary Armed Forces of Colombia, who have refused to lay down their arms after the FARC-government peace treaty came into effect in 2016. The dissidents number some 1,200 armed combatants, with an unknown number of civilian militia supporting them. FARC dissidents have become "an increasing headache" for the Colombian armed forces, as they have to fight them, the EPL, ELN, and Clan del Golfo at the same time. FARC dissidents are led by former mid-level commanders such as alias "Gentil Duarte," alias "Euclides Mora," alias "John 40," alias "Giovanny Chuspas," and alias "Julián Chollo." FARC dissidents have been responsible for several attacks on Colombian armed forces. These fighters are believed to be heavily involved in the production and sale of cocaine. Dissidents of FARC's 1st Front are located in the eastern plains of Colombia. John 40 and their dissident 43rd Front moved into the Amazonas state of western Venezuela. Venezuela has served as the primary location for many FARC dissidents. On July 15, 2018, the Colombian and Peruvian governments launched a joint military effort, known as Operation Armageddon, to combat FARC dissidents. Peru issued a 60-day state of emergency in the Putumayo Province, an area bordering both Colombia and Ecuador. On the first day alone, more than 50 individuals were arrested in the operation, while four cocaine labs were dismantled. The group has attempted to recruit locals in the Putumayo Province in Peru to take up their cause.
=== Male competition === Because palpal, or genital bulb, movements from the males result in the displacement of spermatozoa and other seminal fluid from the female uterus externus, sperm competition exists between males of the P. Phalangioides species. A rival male can attempt to displace the sperm of another male from the female's genital cavity by copulating with her; however, because the copulation duration is greatly decreased in second males, and thus there is less time to displace a rival's sperm, it is unlikely that the spermatozoa of rival, second male would greatly outnumber those of the first male in the uterus externus.
=== Isoforms === There are 3 genes that encode three isoforms of TPC1-3 that differ substantially from each other in their primary sequence (but these differences are preserved across species, such that human and sea urchin TPC1 are more closely related than are human TPC1 and human TPC2). Moreover, the TPC isoforms exhibit different organellar distributions, with TPC1 being found throughout the endo-lysosomal system (although predominantly in recycling and early endosomes) whereas TPC2 shows a more restricted late-endosomal/lysosomal localization.
In 1889, the protectorate and later colony of Italian Somalia was officially established by Italy through various treaties signed with a number of chiefs and sultans; Sultan Yusuf Ali Kenadid first sent a request to Italy in late December 1888 to make his Sultanate of Hobyo an Italian protectorate before later signing a treaty in 1889.
Chicago, Illinois (includes Kenosha, Wisconsin) Clarksville, Tennessee Cincinnati, Ohio Columbia, Missouri Columbus, Ohio Dayton, Ohio Detroit, Michigan Indianapolis, Indiana Las Vegas, Nevada Lexington, Kentucky Louisville, Kentucky Minneapolis–St. Paul, Minnesota Nashville, Tennessee New York – New Jersey (includes Allentown, Pennsylvania) Orlando, Florida Phoenix, Arizona (no locations in Phoenix proper) St. Louis, Missouri Louisville and Columbus also house bulk-manufacturing (grocery-store sales, meat, and bun production) divisions. Company headquarters and the Porcelain Steel Buildings division are in Columbus, Ohio. In the late 20th century, White Castle tried expanding into three new cities, Philadelphia, Kansas City, and Cleveland-Akron. Those restaurants closed within several years. After a several decade hiatus, the company returned to the Kansas City area in 1985 only to leave again in 2001. White Castle entered the Cleveland-Akron area in 1987 and then exited in December 2014.
Sources: en.wikipedia.org
=== Antibody-directed enzyme prodrug therapy === Antibody-directed enzyme prodrug therapy (ADEPT) involves the application of cancer-associated monoclonal antibodies that are linked to a drug-activating enzyme. Systemic administration of a non-toxic agent results in the antibody's conversion to a toxic drug, resulting in a cytotoxic effect that can be targeted at malignant cells. The clinical success of ADEPT treatments is limited.
The neurohypophysial hormones form a family of structurally and functionally related peptide hormones. Their representatives in humans are oxytocin and vasopressin. They are named after the location of their release into the blood, the neurohypophysis (another name for the posterior pituitary). Most of the circulating oxytocin and vasopressin hormones are synthesized in magnocellular neurosecretory cells of the supraoptic nucleus and paraventricular nucleus of the hypothalamus. They are then transported in neurosecretory granules along axons within the hypothalamo-neurohypophysial tract by axoplasmic flow to axon terminals forming the pars nervosa of the posterior pituitary. There, they are stored in Herring bodies and can be released into the circulation on the basis of hormonal and synaptic signals with assistance from pituicytes. Oxytocin mediates contraction of the smooth muscle of the uterus and mammary gland, while vasopressin has antidiuretic action on the kidney, and mediates vasoconstriction of the peripheral vessels. Due to the similarity of the two hormones, there is cross-reaction: oxytocin has a slight antidiuretic function, and high levels of AVP can cause uterine contractions. In common with most active peptides, both hormones are synthesised as larger protein precursors that are enzymatically converted to their mature forms.
In the Meiji period, Japanese clothes began to be westernized and the number of people who wore kimono decreased, so the craftsmen who made netsuke and kiseru with ivory and wood lost their demand. Therefore, they tried to create a new field, ivory sculptures for interior decoration, and many elaborate works were exported to foreign countries or purchased by the Imperial Family. In particular, the works of Ishikawa Komei and Asahi Gyokuzan won praise in Japan.
== See also == Animal testing on invertebrates Microbiome in the Drosophila gut Eating behavior in Insects (Measurement) Fruit flies in space Genetically modified insect Gynandromorphism JETLAG gene List of Drosophila databases Spätzle (gene) Time flies like an arrow; fruit flies like a banana Transgenesis Zebrafish – another widely-used model organism in scientific research Enhancer-FACS-seq
== tRNA genes == Organisms vary in the number of tRNA genes in their genome. For example, the nematode worm C. elegans, a commonly used model organism in genetics studies, has 29,647 genes in its nuclear genome, of which 620 code for tRNA. The budding yeast Saccharomyces cerevisiae has 275 tRNA genes in its genome. The number of tRNA genes per genome can vary widely, with bacterial species from groups such as Fusobacteria and Tenericutes having around 30 genes per genome while complex eukaryotic genomes such as the zebrafish (Danio rerio) can bear more than 10 thousand tRNA genes. In the human genome, which, according to January 2013 estimates, has about 20,848 protein-coding genes in total, there are 497 nuclear genes encoding cytoplasmic tRNA molecules, and 324 tRNA-derived pseudogenes—tRNA genes thought to be no longer functional (although pseudo tRNAs have been shown to be involved in antibiotic resistance in bacteria). One study has shown that the copy number of tRNA genes varies among individuals. As with all eukaryotes, there are 22 mitochondrial tRNA genes in humans. Mutations in some of these genes have been associated with severe diseases like the MELAS syndrome. Regions in nuclear chromosomes, very similar in sequence to mitochondrial tRNA genes, have also been identified (tRNA-lookalikes). These tRNA-lookalikes are also considered part of the nuclear mitochondrial DNA (genes transferred from the mitochondria to the nucleus).
Sources: en.wikipedia.org
The solid is kept cold, dry and dark, typically at minus twenty degrees Celsius, in a sealed container with desiccant. Dissolved material is kept refrigerated and used promptly. Freezing and thawing a solution repeatedly is avoided because it accelerates degradation.
Reversed-phase chromatography with ultraviolet detection gives a purity percentage, while mass spectrometry confirms identity. Amino acid analysis checks the residue composition. Buyers typically request a certificate of analysis showing these measurements for the specific lot.
It is not authorised as a medicine in the United States or the European Union. Material is sold there as a research chemical or cosmetic ingredient. Some related short peptides are registered drugs in Russia, which is a distinct national situation rather than a general approval.
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.