A practical reference on AEDG: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-09-22. Anything still debated is marked as such rather than presented as settled.
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.
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.
Storage and handling follow conventional peptide practice. Lyophilized epitalon is typically kept refrigerated or frozen, protected from moisture and light, and allowed to equilibrate to room temperature before opening to avoid condensation. Once dissolved, aqueous solutions are usually stored cold and used within a short period, since dilute peptide solutions can support microbial growth and may slowly degrade. The absence of cysteine and methionine reduces, but does not eliminate, oxidation concerns during long-term storage.
Regulatory status varies by country and is not harmonized. Epitalon is not an approved drug in major Western jurisdictions. In some countries it is sold as a research chemical, and in others it has appeared in products marketed for other categories. This inconsistent status means that purity, labeling accuracy, and documentation differ widely between suppliers, and verification of identity and purity through independent analysis is the usual way buyers assess a given lot.
Epitalon appears in the literature primarily through a small number of research groups, most of them associated with the St. Petersburg Institute of Bioregulation and Gerontology. Publications describe cell culture experiments, animal studies, and a limited number of small human studies. Independent replication outside this network is sparse. As a result, reviews of the topic usually separate descriptive reports of observed effects from the question of whether those effects generalize, and they note the difficulty of comparing studies that use different preparations and endpoints.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
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.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
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.
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.
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.
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.
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.
In chemistry, there are three definitions in common use of the word "base": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century. In 1884, Svante Arrhenius proposed that a base is a substance which dissociates in aqueous solution to form hydroxide ions OH−. These ions can react with hydrogen ions (H+ according to Arrhenius) from the dissociation of acids to form water in an acid–base reaction. A base was therefore a metal hydroxide such as NaOH or Ca(OH)2. Such aqueous hydroxide solutions were also described by certain characteristic properties. They are slippery to the touch, can taste bitter, and change the color of pH indicators (e.g., turn red litmus paper blue). In water, by altering the autoionization equilibrium, bases yield solutions in which the hydrogen ion activity is lower than it is in pure water, i.e., the water has a pH higher than 7.0 at standard conditions. A soluble base is called an alkali if it contains and releases OH− ions quantitatively. Metal oxides, hydroxides, and especially alkoxides are basic, and conjugate bases of weak acids are weak bases. Bases and acids are seen as chemical opposites because the effect of an acid is to increase the hydronium (H3O+) concentration in water, whereas bases reduce this concentration. A reaction between aqueous solutions of an acid and a base is called neutralization, producing a solution of water and a salt in which the salt separates into its component ions.
=== Campaigning === Heseltine was not one to befriend and gossip with colleagues or backbenchers. He did not regard this as an insurmountable problem, as neither Heath nor Thatcher had been particularly "clubbable" either. From about the mid-1970s, he began a campaign of addressing local associations, sometimes using a helicopter to speak to several in one day. Heseltine had often had a reputation for being very cold and aloof with backbench MPs and party activists (Steven Norris said that after a visit to his constituency in 1983, local activists used a poster of Heseltine as a dartboard). However, in 1986–1990 he was a frequent visitor to local constituency dinners, although he usually attacked Labour rather than the Conservative government, and he used his wealth to afford a chauffeur and a helicopter. Heseltine campaigned in 100 constituencies in the 1987 election, attracting more publicity than many Cabinet ministers, although seldom mentioning Thatcher by name. During this period Heseltine enjoyed excellent relations with the media: among TV journalists he was in regular touch with Elinor Goodman of Channel 4 News (herself a former Haymarket employee), James Mates of ITN (son of his lieutenant Michael Mates) and John Cole, whilst among print journalists he was close to his old friend Anthony Howard (Deputy Editor of the Observer), Peter Jenkins, and especially close to Anthony Bevins of The Independent and the young Alastair Campbell of the Daily Mirror.
Human and mouse protein kinases in UniProt: classification and index Kinase.Com: Genomics, evolution and large-scale analysis of protein kinases (non-commercial). KinMutBase: A registry of disease-causing mutations in protein kinase domains Archived 2022-06-15 at the Wayback Machine KLIFS (Kinase-Ligand Interaction Fingerprints and Structures) Database -- analysis of kinase structures and kinase-inhibitor interactions KinCore: the Kinase Conformation Resource: A web resource for protein kinase sequence, structure and phylogeny Kinomer: A multilevel HMM library for the classification and functional annotation of eukaryotic protein kinases.
All of these instruments provide a high mass accuracy (<2–3 ppm with external calibrant and <1–2 ppm with internal), a high resolving power (up to 240,000 at m/z 400), a high dynamic range and high sensitivity.
==== Class A sub-family ==== Class A enzymes methylate specific adenosine residues on rRNA and/or tRNA. In other words, they are RNA base-modifying radical SAM enzymes. The most mechanistically well-characterized are enzymes RlmN and Cfr. Both enzymes methylates substrate by adding a methylene fragment originating from SAM molecule. Therefore, RlmN and Cfr are considered methyl synthases instead of methyltransferases.
Sources: en.wikipedia.org
== Reactive dyes == The dyes used in this type of chromatography are inexpensive and generally available as they are from textile industries called reactive dye. It contains chromophores that are often attached to a triazine ring. In textile industries, reactive dyes are used to dye material like cotton which is cellulose. Commonly used reactive dyes for chromatography can be separated according to their color index name or functional group. Noted that each company has different trade names and slightly different formulas of the reactive dyes. Usually available commercially with sepharose as the supporting matrix in the form of packed columns.
=== South America === Argentina: President Javier Milei celebrated the capture of Maduro and his wife by posting on social media: "liberty advances, ¡Viva la libertad, carajo!". In an interview with local media, Milei said that Maduro "clung on to power" and ran a regime "rigging elections", reaffirming that his capture was "excellent news for the free world". On 7 January, Milei expressed support for the US taking control of the Venezuelan oil industry, arguing that it will "cut (the) supply of communists." Bolivia: The Ministry of Foreign Affairs expressed support for the Venezuelan people in their path to recover "democracy, constitutional order, and human rights", while reaffirming Bolivia's commitment to Venezuela's stability and humanitarian assistance. President Rodrigo Paz later stated that "freedom is not negotiable" and that "the way out for Venezuela is to respect the vote". On January 4 Bolivia imposed travel restrictions to members of the security forces of Venezuela as well as Venezuelan officials and former officials of the Maduro government. Brazil: President Luiz Inácio Lula da Silva condemned the strikes and the capture of Maduro, referring to them as a "very serious affront to the sovereignty of Venezuela and a extremely dangerous precedent to all the international community". On 4 January 2026, Brazil, Spain, Chile, Colombia, Mexico, and Uruguay issued a joint statement to express their "profound concern and firm rejection of the military actions carried out unilaterally in Venezuelan territory" by the United States.
The cords of Billroth (also known as splenic cords or red pulp cords) are found in the red pulp of the spleen between the sinusoids, consisting of fibrils and connective tissue cells with a large population of monocytes and macrophages. These cords contain half of the human body's monocytes as a reserve so that, after tissue injury, these monocytes can move in and aid locally sourced monocytes in wound healing. Erythrocytes pass through the cords of Billroth before entering the sinusoids. The passage into the sinusoids may be seen as a bottleneck, where erythrocytes need to be flexible in order to pass through. In disorders of erythrocyte shape and/or flexibility, such as hereditary spherocytosis, erythrocytes fail to pass through and get phagocytosed, causing extravascular hemolysis.
=== CD38 === CD38 is an enzyme that triggers inflammatory responses and type II CD38 contains an ecto-NADase or extracellular NADase, whereas type II CD38 contains an intracellular cADPR. CD38 consumes NAD, which can produce second messengers that help regulate immune activity. Cells that are programmed for cell death or apoptosis releases NAD+, and type II CD38 help recycle the extracellular NAD+ released from apoptosis, where both products of NADase, ADP-ribose and nicotinamide, can be used to resynthesize NAD+ via the NAD+ synthesis pathway. ADP-ribose must be converted to adenosine in order to enter the NAD+ synthesis pathway, where ADP-ribose first gets converted to AMP and then AMP gets converted to adenosine via non-classical adenosine generational pathway. The other product nicotinamide is membrane permeable, which allows the molecule to re-enter the NAD synthesis pathway more easily. CD38 NADase is also found in tissues and cells other than T cells, and CD38 is one of the main forms of NADase activity in mammals.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
Identity is normally confirmed by mass spectrometry, which checks the measured mass against the expected value near 390 daltons. Reverse-phase high-performance liquid chromatography is used alongside it to assess purity. Amino acid analysis can provide additional composition data.