telomerase raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-11-10. Anything still debated is marked as such rather than presented as settled.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Published work on this compound consists mainly of in vitro experiments, animal studies, and small clinical investigations, a substantial share of which appeared in Russian-language journals. Sample sizes are generally small, control conditions differ between studies, and several endpoints rely on markers whose clinical meaning is itself debated. Reviews of the longevity field treat the peptide as an early example of telomerase-directed research rather than an established intervention. Regulatory treatment varies by country: some jurisdictions place it under prescription controls, others treat it as a laboratory material, and importation may be restricted regardless of local status.
Epitalon is a synthetic tetrapeptide whose sequence is alanine–glutamate–aspartate–glycine, commonly abbreviated AEDG. It was developed in Russia during the 1980s and 1990s by investigators associated with the St. Petersburg Institute of Bioregulation and Gerontology, who studied short peptides as regulators of gene expression and tissue function. The alternative spelling epithalon appears interchangeably in the literature, and the two names refer to the same molecule. Outside Russia it is encountered chiefly as a research chemical rather than a licensed medicine, and it holds no approval from the United States Food and Drug Administration or the European Medicines Agency.
The peptide is a synthetic analogue of epithalamin, a preparation extracted from bovine pineal glands. Investigators sought a short, chemically defined molecule that would reproduce some of the endocrine and gerontological observations attributed to the glandular extract. Proposed mechanisms centre on induction of telomerase activity, an effect reported in cultured human somatic cells in the early 2000s, together with influences on melatonin secretion and neuroendocrine regulation. Those mechanisms remain incompletely characterised, and the reported telomerase response has not been consistently reproduced by independent groups working in comparable systems.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Derived from the four constituent residues |
| Molecular mass | About 390.35 Da | Monoisotopic value, confirmed by mass spectrometry |
| Residue sequence | Ala-Glu-Asp-Gly | Read from the N-terminus to the C-terminus |
| Common synonyms | Epithalon; AEDG | Both forms appear in reference catalogues |
| Net charge near neutral pH | Negative | Two acidic side chains give a low isoelectric point |
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.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
== Clinical Significance == Single-nucleotide polymorphisms (SNPs) in the FGFR1OP2 gene were found to lead to edentulism in the mandible of a small Korean population (134 subjects aged 60–80 years). Also, when FGFR1OP2 is fused to FGFR1, 8p11 myeloproliferative syndrome can result.
=== Counting methods === In order to quantify the number of substitutions, one may reconstruct the ancestral sequence and record the inferred changes at sites (straight counting – likely to provide an underestimate); fitting the substitution rates at sites into predetermined categories (Bayesian approach; poor for small data sets); and generating an individual substitution rate for each codon (computationally expensive). Given enough data, all three of these approaches will tend to the same result.
For me, it is an honour. The discovery of element 118 was by scientists at the Joint Institute for Nuclear Research in Russia and at the Lawrence Livermore National Laboratory in the US, and it was my colleagues who proposed the name oganesson. My children and grandchildren have been living in the US for decades, but my daughter wrote to me to say that she did not sleep the night she heard because she was crying. The naming ceremony for moscovium, tennessine, and oganesson was held on 2 March 2017 at the Russian Academy of Sciences in Moscow. In a 2019 interview, when asked what it was like to see his name in the periodic table next to Einstein, Mendeleev, the Curies, and Rutherford, Oganessian responded:
== Classification == There are two subtypes of this receptor known at present, defined as CCKA and CCKB (also called CCK-1 and CCK-2, respectively). The CCKA receptor is mainly expressed in the small intestine, and is involved in the regulation of enzyme secretion by the pancreas, secretion of gastric acid in the stomach, intestinal motility and signaling of satiety (fullness). The CCKB receptor is expressed mainly in the central nervous system, and has functions relating to anxiety and the perception of pain. Antagonists for the CCK receptors can thus have multiple functions in both the gut and brain.
=== Contraindications === Ceftriaxone should not be used in those with an allergy to ceftriaxone or any component of the formulation. Although there is negligible cross-reactivity between penicillins and third-generation cephalosporins, caution should still be used when using ceftriaxone in penicillin-sensitive patients. Caution should be used in people who have had previous severe penicillin allergies. It should not be used in hyperbilirubinemic neonates, particularly those who are premature because ceftriaxone is reported to displace bilirubin from albumin binding sites, potentially causing bilirubin encephalopathy. Concomitant use with intravenous calcium-containing solutions/products in neonates (≤28 days) is contraindicated even if administered through different infusion lines due to rare fatal cases of calcium-ceftriaxone precipitations in neonatal lungs and kidneys.
Sources: en.wikipedia.org
S-Nitrosoglutathione (GSNO) is an endogenous S-nitrosothiol (SNO) that plays a critical role in nitric oxide (NO) signaling and is a source of bioavailable NO. NO coexists in cells with SNOs that serve as endogenous NO carriers and donors. SNOs spontaneously release NO at different rates and can be powerful terminators of free radical chain propagation reactions, by reacting directly with ROO• radicals, yielding nitro derivatives as end products. NO is generated intracellularly by the nitric oxide synthase (NOS) family of enzymes: nNOS, eNOS and iNOS while the in vivo source of many of the SNOs is unknown. In oxygenated buffers, however, formation of SNOs is due to oxidation of NO to dinitrogen trioxide (N2O3). Some evidence suggests that both exogenous NO and endogenously derived NO from nitric oxide synthases can react with glutathione to form GSNO.
The preferred, native cleavage sequence was first identified by examining the cut sites in the native polyprotein substrate for recurring sequence. The consensus for these native cut sites is ENLYFQ\S where '\' denotes the cleaved peptide bond. Residues of the substrate are labelled P6 to P1 before the cut site and P1' after the cut site. Early works also measured cleavage of an array of similar substrates to characterise how specific the protease was for the native sequence. Studies have subsequently used sequencing of cleaved substrates from a pool of randomised sequences to determine preference patterns. Although ENLYFQ\S is the optimal sequence, the protease is active to a greater or lesser extent on a range of substrates (i.e. shows some substrate promiscuity). The highest cleavage is of sequences closest to the consensus EXLYΦQ\φ where X is any residue, Φ is any large or medium hydrophobe and φ is any small hydrophobic or polar residue. Although this sequence is the optimal, sequences with disfavoured residues at some positions can still be cleaved if the rest of the sequence is optimal. Specificity is endowed by the large contact area between enzyme and substrate. Proteases such as trypsin have specificity for one residue before and after the cleaved bond due to a shallow binding cleft with only one or two pockets that bind the substrate side chains. Conversely, viral proteases such as TEV protease have a long C-terminal tail which completely covers the substrate to create a binding tunnel.
== Regulation and composition == CoQ10 is not approved by the U.S. Food and Drug Administration (FDA) for the treatment of any medical condition. However, it is sold as a dietary supplement not subject to the same regulations as medicinal drugs, and is an ingredient in some cosmetics and energy drinks. The manufacture of CoQ10 is not regulated, and different batches and brands may vary significantly.
Warsaw's refusal to allow the Red Army to operate on Polish territory doomed the Western efforts. The final contentious Allied-Soviet exchanges took place on 21 and 23 August 1939.[b] The Stalinist state was the target of an intense German counter-initiative and was concurrently involved in increasingly effective negotiations with Hitler's agents. On 23 August, an outcome contrary to the exertions of the Allies became a reality: in Moscow, Germany and the Soviet Union hurriedly signed the Molotov–Ribbentrop Pact, which secretly provided for the dismemberment of Poland into Nazi- and Soviet-controlled zones.
Sources: en.wikipedia.org
=== Allergy === HLA-G has links to allergenic responses in the body. Soluble HLA-G levels are higher in the serum of people with allergic rhinitis, or hay fever. Additionally, single nucleotide polymorphisms in HLA-G have been connected to an increased likelihood of having asthma. Papillary cells expressing HLA-G were found in patients with atopic dermatitis.
=== Enantioselective synthesis of chiral nitriles === Using chiral pool starting materials, enantioselective synthesis enables access to α-chiral nitrile-containing compounds in eutomeric form, such as vildagliptin and saxagliptin. Conventional transformations can introduce the nitrile functionality; for example, an enantiomerically pure amide or oxime derived from naturally enantiopure proline may be dehydrated. The applicability of such strategies depends on the specific target molecule. Asymmetric cyanation reactions are also established. Of particular importance is the asymmetric hydrocyanation of carbonyl compounds (see section on cyanohydrin preparation). In addition, numerous asymmetric hydrocyanations of imines have been developed, affording enantiomerically pure α-aminonitriles.
In May 2014, researchers announced that they had successfully introduced two new artificial nucleotides into bacterial DNA, alongside the four naturally occurring nucleotides, and by including individual artificial nucleotides in the culture media, were able to passage the bacteria 24 times; they did not create mRNA or proteins able to use the artificial nucleotides.
Sources: en.wikipedia.org
It is a four-amino-acid peptide built from alanine, glutamate, aspartate and glycine in that order. Its formula is C14H22N4O9, and it is made by chemical synthesis rather than extracted from tissue. The synthetic peptide is a single defined molecule, unlike the pineal extracts it is often compared with.
No. The two spellings refer to the same tetrapeptide, and the difference reflects transliteration from Russian. Laboratories and catalogues use both forms interchangeably. The material is also indexed as AEDG, taken from the one-letter codes of its residues.
Epithalamin is a mixed preparation derived from animal pineal tissue and contains many peptides. Epitalon is one synthetic sequence chosen for study from that broader mixture. Statements about one do not transfer directly to the other.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine–glutamate–aspartate–glycine, also written AEDG. It was developed in Russian gerontology research and is studied for proposed effects on telomerase, melatonin regulation, and neuroendocrine function. It is not an approved pharmaceutical in the United States or the European Union.