AEDG raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-23. Anything still debated is marked as such rather than presented as settled.
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.
Discussions in the literature often conflate three distinct entities: the pineal extract epithalamin, the isolated tetrapeptide AEDG, and commercial preparations sold under similar names. Reviews citing older Russian-language studies sometimes omit detail on purity, route of administration and control groups, which makes cross-study comparison difficult. Researchers working with the compound generally note the need for independent replication, standardized enzyme assays, and clearer reporting of peptide identity. These caveats are relevant when weighing claims that appear in secondary sources rather than in primary reports.
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.
| 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 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.
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.
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.
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
It can also cause sexual side effects, galactorrhoea, infertility, gynecomastia, and, with chronic use, reduced bone mineral density leading to breaks, all of which are associated with increased prolactin secretion. Alpha α1 adrenergic receptors: This action accounts for the orthostatic hypotensive effects and perhaps some of the sedating effects of risperidone. Alpha α2 adrenergic receptors: Risperidone's action at these receptors may cause greater positive, negative, affective, and cognitive symptom control. Histamine H1 receptors: effects on these receptors account for its sedation and reduction in vigilance. This may also lead to drowsiness and weight gain. 5-HT2A receptor: Risperidone’s atypicality is relatively strong in terms of its binding preference for 5-HT2A receptors over dopamine D2 receptors. However, clozapine is generally considered stronger in this regard. Clozapine differs in that it has lower overall receptor affinity compared to some other atypical antipsychotics, but still maintains an approximate 4-fold higher affinity for 5-HT2A receptors relative to D2 receptors. Among three atypical antipsychotics often noted for significant 5-HT2A receptor blockade (risperidone, olanzapine, and clozapine), risperidone shows the highest degree of receptor occupancy in a dose-dependent comparison. At approximately 20 mg risperidone and 6 mg olanzapine, reported receptor occupancies are around 93–95%, respectively. Clozapine ranks third when compared using chlorpromazine equivalents.
== Research == Bifidobacterium animalis subspecies lactis BB-12 administered in combination with other probiotics has shown "a trend toward increased remission" in a study of 32 patients with ulcerative colitis. Research on Bifidobacterium animalis supplementation in preterm infants, as detailed in the systematic review by Szajewska et al., a meta-analysis of four randomized controlled trials (RCTs) involving a total of 324 infants, has shown promising results. These include increased fecal bifidobacteria counts, reduced Enterobacteriaceae and Clostridium spp counts, as well as improvements in stool pH, fecal calprotectin concentrations, fecal immunoglobulin A levels, and short-chain fatty acid concentrations. However, the analysis did not find significant effects on the risk of necrotizing enterocolitis stage ≥2, risk of sepsis, or use of antibiotics compared to controls.
where χi denotes the mole fraction of component i. For greater accuracy, the critical point can be calculated using equations of state, such as the Peng–Robinson, or group-contribution methods. Other properties, such as density, can also be calculated using equations of state.
Sources: en.wikipedia.org
Dressings are usually secured with adhesive tape and/or a bandage. Many dressings today are produced as an "island" surrounded by an adhesive backing, ready for immediate application – these are known as island dressings.
=== Synthesis and release === The corpus luteum produces the 6-kDa peptide hormone relaxin. Prolactin and insulin-like growth factor binding protein are two examples of the hormones and growth factors that relaxin can stimulate the secretion of. Preprorelaxin is the collective term for the signal peptide, B chain, C peptide, and A chain found in the coding area of human relaxin genes. The signal peptide is cleaved to produce prorelaxin. Prohormone convertases, such as prohormone convertase-1 and prohormone convertase-2, can convert prorelaxin to mature relaxin.
=== Health hazards === Honey is generally safe when taken in typical food amounts, but it may have various, potential adverse effects or interactions in combination with excessive consumption, existing disease conditions, or drugs. Included among these are mild reactions to high intake, such as anxiety, insomnia, or hyperactivity in about 10% of children, according to one study. No symptoms of anxiety, insomnia, or hyperactivity were detected with honey consumption compared to placebo, according to another study. Honey consumption may interact adversely with existing allergies, high blood sugar levels (as in diabetes), or anticoagulants used to control bleeding, among other clinical conditions. People who have a weakened immune system may be at risk of bacterial or fungal infection from eating honey.
Sources: en.wikipedia.org
In addition to arthropods, marine animals also contain nitrile compounds. These include bursatellin from broad-footed snails of the genus Bursatella and the calyculins isolated from sponges. The albanitriles from sponges of the genus Mycale are linear compounds (chain length 16 to 18 carbon atoms) bearing a nitrile group at one or both termini and several additional C≡C triple bonds.
=== Alternative stop codons === There are variations on the standard genetic code, and alternative stop codons have been found in the mitochondrial genomes of vertebrates, Scenedesmus obliquus, and Thraustochytrium.
=== 1980s === 1980: introduces low-protein binding Durapore polyvinylidene fluoride membrane 1987: listed on the New York Stock Exchange 1987: achieves $500 million revenue 1988: opens membrane manufacturing plant in County Cork, Ireland
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 usual approach is reversed-phase HPLC with ultraviolet detection, reported as a percentage of total peak area. Mass spectrometry is used alongside chromatography to confirm identity rather than purity alone.