The short version of Reversed-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-02-06 and is reviewed periodically as new material appears.
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.
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.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
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.
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.
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.
Parafollicular cells, also called C cells, are neuroendocrine cells in the thyroid. They are called C cells because the primary function of these cells is to secrete calcitonin. They are located adjacent to the thyroid follicles and reside in the connective tissue. These cells are large and have a pale stain compared with the follicular cells. In birds and teleost fishes these cells occupy a structure outside the thyroid gland named the ultimopharyngeal body.
Dom Pothier died at the old priory of Conques, Belgium in 1923; the Bishop of Luxembourg and six prelates attended his funeral at Clervaux abbey, Luxembourg (his remains later were transferred to Saint-Wandrille in 1962). The exiled community of St Wandrille's Abbey, under Dom Pothier as Abbot, founded in 1912 a new priory in Canada, Saint Benedict Abbey, Quebec, which later became independent within the Solesmes Congregation.
== Honors and awards == Maroon received the Distinguished Alumni Service Award from Indiana University in Bloomington in 2011, recognizing his achievements as an undergraduate. In 2018, he was named Humanitarian of the Year by the Jerome Bettis Bus Stops Here Foundation for his contributions to health and wellness. In 2022, he received the Distinguished Alumni Award from the Indiana University School of Medicine. In 2025, he was awarded the Ellis Island Medal of Honor, which honors individuals who have made major contributions to American society while celebrating their cultural heritage.
Sources: en.wikipedia.org
==== The Congress of Vienna ==== After Napoleon's defeat, a new European order was established at the Congress of Vienna, which met in the years 1814 and 1815. Adam Jerzy Czartoryski, a former close associate of Emperor Alexander I, became the leading advocate for the Polish national cause. The Congress implemented a new partition scheme, which took into account some of the gains realized by the Poles during the Napoleonic period. The Duchy of Warsaw was replaced in 1815 with a new Kingdom of Poland, unofficially known as Congress Poland. The residual Polish kingdom was joined to the Russian Empire in a personal union under the Russian tsar and it was allowed its own constitution and military. East of the kingdom, large areas of the former Polish–Lithuanian Commonwealth remained directly incorporated into the Russian Empire as the Western Krai. These territories, along with Congress Poland, are generally considered to form the Russian Partition. The Russian, Prussian, and Austrian "partitions" are informal names for the lands of the former Commonwealth, not actual units of administrative division of Polish–Lithuanian territories after partitions. The Prussian Partition included a portion separated as the Grand Duchy of Posen. Peasants under the Prussian administration were gradually enfranchised under the reforms of 1811 and 1823. The limited legal reforms in the Austrian Partition were overshadowed by its rural poverty. The Free City of Cracow was a tiny republic created by the Congress of Vienna under the joint supervision of the three partitioning powers.
A few producers such as Casa Noble (for their "Crystal" expression) and Corzo (for their añejo expression) have experimented with distilling the product a third time, but this has not caught on as a trend, and some have said it removes too much of the agave flavor from the tequila. At this point the tequila is either bottled as silver tequila or it is pumped into wooden barrels to age, where it develops a mellower flavor and amber color. The differences in taste between tequila made from valley and highland agave plants can be noticeable. Plants grown in the highlands often yield sweeter and fruitier-tasting tequila, while valley agaves give the tequila an earthier flavor.
==== Sustained-release formulation ==== A sustained-release tablet formulation of oral micronized progesterone (also known as "oral natural micronized progesterone sustained release" or "oral NMP SR") has been marketed in India under the brand names Dubagest SR, Gestofit SR, and Susten SR among others. It shows a slow and smooth profile of progesterone release over 24 hours and has an elimination half-life of 18 hours. This results in steadier and more sustained progesterone levels as well as minimization of the neurosteroid-related side effects of oral progesterone such as sedation.
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=== Contemporary era === Despite another conscription crisis in Quebec in 1944, Canada finished the war with a large army and strong economy. After two referendums, Newfoundlanders voted to join Canada in 1949 as a province. Canada's post-war economic growth, combined with the policies of successive Liberal governments, led to the emergence of a new Canadian identity, marked by the adoption of the maple leaf flag in 1965, the implementation of official bilingualism (English and French) in 1969, and the institution of official multiculturalism in 1971. Socially democratic programs were also instituted, such as Medicare, the Canada Pension Plan, and Canada Student Loans, though provincial governments, particularly Quebec and Alberta, opposed many of these as incursions into their jurisdictions.
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== Scientific contributions == Du Vigneaud's career was characterized by an interest in sulfur-containing peptides, proteins, and especially peptide hormones. Even before his Nobel-Prize-winning work on elucidating and synthesizing oxytocin and vasopressin via manipulating the AVP gene, he had established a reputation from his research on insulin, biotin, transmethylation, and penicillin. He also carried out a series of structure-activity relationships for oxytocin and vasopressin, perhaps the first of their type for peptides. That work culminated in the publication of a book entitled A Trail of Research in Sulphur Chemistry and Metabolism and Related Fields.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.