Everything below concerns counterion. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-09-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
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.
Verification of a sample usually begins with reversed-phase high-performance liquid chromatography, which resolves the peptide from truncated sequences and other impurities and expresses purity as a percentage of total peak area. Mass spectrometry by electrospray ionisation or matrix-assisted laser desorption supplies an independent check, because the measured mass can be compared against the theoretical value for AEDG. Amino acid analysis or tandem mass spectrometry sequencing can confirm residue order. Each of these methods answers a different question: a purity figure does not establish identity, and an identity match does not establish how much of the material is intact peptide.
The molecule is a short, linear, hydrophilic peptide that dissolves readily in water or aqueous buffer. Its principal chemical liabilities are hydrolytic rather than oxidative, since it contains no cysteine, methionine, or tryptophan residues. The aspartate–glycine step is a recognised site for aspartimide formation under mildly acidic or basic conditions, generating isoaspartate and succinimide-related products over time. Desiccated lyophilised powder held at −20 °C is comparatively stable, whereas dilute solutions degrade faster and are best frozen as single-use aliquots rather than thawed repeatedly.
In 2011, a randomized controlled trial with 740 patients found cytisine improved 12-month abstinence from nicotine from 2.4% with placebo to 8.4% with cytisine. A 2013 meta-analysis of eight studies demonstrated that cytisine has similar effectiveness to varenicline but with substantially lower side effects. A 2014 systematic review and economic evaluation concluded that cytisine was more likely to be cost-effective for smoking cessation than varenicline. It is on the World Health Organization's List of Essential Medicines.
== Material properties in the space environment == There are several unique differences between the properties of materials in space compared to the same materials on the Earth. These differences can be exploited to produce unique or improved manufacturing techniques.
WALP peptides are a class of synthesized, membrane-spanning α-helices composed of tryptophan (W), alanine (A), and leucine (L) amino acids. They are designed to study properties of proteins in lipid membranes such as orientation, extent of insertion, and hydrophobic mismatch.
Sources: en.wikipedia.org
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The role that microRNAs play in cancer development and metastasis is under much scientific investigation and it is yet to be demonstrated whether microRNA mimics or antagomirs may serve as standard clinical treatments to suppress EMT or oncogenic microRNAs in cancers.
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Sources: en.wikipedia.org
== Bibliography == J. Samuel Walker (November 1, 2000). Permissible Dose: A History of Radiation Protection in the Twentieth Century. University of California Press. ISBN 978-0-520-92484-0. Limited preview in Google Books. K. N. Govinda Rajan (July 28, 2017). Radiation Safety in Radiation Oncology. CRC Press. ISBN 978-1-4987-6226-7. Limited preview in Google Books. Strahlengefahrdung und Strahlenschutz / Radiation Exposure and Radiation Protection. Springer-Publisher. March 13, 2013. ISBN 978-3-642-82229-2. Limited preview in Google Books J. Samuel Walker (April 2001). Short History of Nuclear Regulation, 1946–1999. DIANE Publishing. ISBN 978-0-7567-0929-7.Limited preview in Google Books. Ashley W. Oughterson, Shields Warren: Medical Effects of the Atomic Bomb in Japan. Volume VIII.8 aus der National Nuclear Energy Series zum Manhattan Project, McGraw-Hill Book Company, 1956. Carl Voegtlin, Harold C. Hodge: Pharmacology and Toxicology of Uranium Compounds. Volume VI.1, Part I and Part II (with a Section on the Pharmacology and Toxicology of Fluorine and Hydrogen Fluoride) from the National Nuclear Energy Series to the Manhattan Project, McGraw-Hill Book Company, 1949. Henry DeWolf Smyth (written on the request of Maj. Gen. L. R. Groves): Atomic Energy for Military Purposes. The official report on the development of the atomic bomb under the auspices of the United States Government, 1940–1945. Princeton University Press, 1946. James E. Grindler (Argonne National Laboratory): The Radiochemistry of Uranium.
Projects Accomplished: Detectability of Corticosteroid in various Indian preparations: Effect on Endogenous steroid profile. Characteristics of IEF Patterns and SDS-PAGE Result of Indian EPO Biosimilars. Establishing Reference Range for Endogenous Steroids in Indian Sportspersons and to study the effect of ethnicity and steroid abuse on delta values of endogenous steroids. Analytical strategies in the development and utilization of mass spectrometric method for analysis of Stimulants & Narcotics. Effect of Ethnicity and Anabolic Steroid Abuse on Delta Value of Endogenous Steroids. Rapid Screening in Doping Analysis: Separation and Detection of Doping Agents be Liquid and Gas Chromatographic Mass Spectrometric Analysis. Current Projects: Detection of Synthetic glucocortico steroids, stimulants and anabolic steroids in Indian herbal drugs and supplements. Discrimination of biological and synthetic origin of anabolic steroids in human urine: Correlation between GCMSD & Isotope Ratio Mass Spectrometry. An Analytical approach for the Screening of Performance Enhancing Substances from various Dietary Supplements & to study their excretion profile using Chromatographic-Mass Spectrometric Technique. Development of analytical tools for the Detection and Identification of performance enhancing Peptides in Biological Specimen. An analytical approach for the Detection of Corticosteroids in Human and Horse Biological Specimen using Chromatographic and Mass Spectrometric Technique.
==== Pneumococcal vaccine ==== In 2010, as part of a 10-year pneumococcal vaccine Advance Market Commitment, the companies GlaxoSmithKline (GSK) and Pfizer were both allocated $225 million in AMC subsidies to provide 30 million doses annually at a maximum tail price of $3.50 per dose ($10.50 per child for three doses). In 2011, Médecins Sans Frontières (MSF) recommended that Gavi change the ways in which it procures vaccines. MSF argued that the Advance Market Commitment had transferred more money to GSK and Pfizer than the Gavi grants had transferred to low-cost suppliers for technology transfer and product development. MSF said that large pharmaceutical multinationals had been found to put very high markups on prices, and internationally certified vaccine could be made for about 40% less cost by smaller companies in India and China, despite patent-related obstacles. In January 2015, MSF also called upon GSK and Pfizer to cut the price of the pneumococcal vaccine to US$5 per child in developing countries, a price they estimated as competitive. They said that, as Pfizer had made $16 billion in revenue on pneumococcal vaccine in the last four years, a larger price cut would be affordable. In early 2016, they ran the "A fair shot" campaign to pressure GSK and Pfizer to drop prices. Pfizer said that they were already selling the vaccine at "far below" cost, while GSK said that the price enabled them to "just about" cover their costs, and "To discount it further would threaten our ability to supply it to these countries in the long-term".
Sources: en.wikipedia.org
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.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
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.