tetrapeptide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-02-11. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| 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 |
The peptide emerged from research carried out in Saint Petersburg from the late 1980s onward, where investigators searched for shorter active fragments of a pineal preparation known as epithalamin. The name epitalon was chosen to reflect that parent extract. Early reports described effects on neuroendocrine markers and on the lifespan of laboratory animals. Much of that work appeared in Russian-language journals, with English translations following later, which affects how readily the original protocols can be assessed by outside groups.
Published studies on epitalon are dominated by a small number of research groups, and independent replication in other laboratories remains limited. Proposed mechanisms include activation of telomerase and modulation of melatonin rhythms, but the evidence for either rests mainly on cell cultures and animal models. Whether the peptide produces comparable effects in humans is an open question, and the absence of large controlled trials means the literature is best read as exploratory rather than settled.
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.
==== Distribution ==== Spironolactone and its metabolite canrenone are highly plasma protein bound, with percentages of 88.0% and 99.2%, respectively. Spironolactone is bound equivalently to albumin and α1-acid glycoprotein, while canrenone is bound only to albumin. Spironolactone and its metabolite 7α-thiospironolactone show very low or negligible affinity for sex hormone-binding globulin (SHBG). In accordance, a study of high-dosage spironolactone treatment found no change in steroid binding capacity related to SHBG or to corticosteroid-binding globulin (CBG), suggesting that spironolactone does not displace steroid hormones from their carrier proteins. This is in contradiction with widespread statements that spironolactone increases free estradiol levels by displacing estradiol from SHBG. Spironolactone appears to cross the blood–brain barrier.
The Ukrainian General Staff said that Russia launched sixteen missiles and thirty five Shahed drones at Kyiv and other cities in Ukraine, injuring five people in Kyiv. Ukraine claimed to have shot down all drones. Other attacks occurred in the Kharkiv, Kherson, Mykolaiv and Odesa regions. Rocket fire was also reported along with airstrikes. Ukrainian Air Force spokesperson Colonel Yurii Ihnat said that there were "seven aircraft and up to eight launches of Kh-22 cruise missiles" at Odesa Oblast. Many of the missiles were believed to have self-destructed due to their age. One missile was believed to have hit a food storage warehouse in Odesa starting a fire. The missiles were fired from Tu-22 bombers. The attacks occurred on the eve of celebrations of Victory Day in Russia on 9 May. Russia again blocked grain exports from Ukraine, putting about 90 ships in waiting.
Strobilanthes alternata (synonym Hemigraphis alternata), may be known as red ivy, red-flame ivy, or waffle plant, is a member of the family Acanthaceae native to Java. It is a prostrate plant with purple colored leaves.
Some authors have criticized the rule of five for the implicit assumption that passive diffusion is the only important mechanism for the entry of drugs into cells, ignoring the role of transporters. For example, O'Hagan and co-authors wrote as follows:This famous "rule of 5" has been highly influential in this regard, but only about 50 % of orally administered new chemical entities actually obey it. Studies have also demonstrated that some natural products break the chemical rules used in Lipinski filters such as macrolides and peptides.
failed wars like Mr Galloway, who beats an established party, should be instantly savaged as a self-serving demagogue." In October 2013, the Total Politics magazine published an interview with Galloway in which he admitted: "I like elections more than I like serving", and said that he found being an MP was "2% terrifying, and 98% tedium." By 2013, he was a prolific user of Twitter where he had over 116,000 followers. In late 2013, Galloway became Leader of the Respect Party.
Sources: en.wikipedia.org
Come What(ever) May is the second studio album by American rock band Stone Sour, released on August 1, 2006, by Roadrunner Records. It was recorded and produced by Nick Raskulinecz and the band at Studio 606 in Los Angeles, California. Writing for the album began as early as 2003 when vocalist Corey Taylor and guitarist James Root were writing material for their other band, Slipknot. In January 2006, Stone Sour began recording their second album, during which time drummer Joel Ekman left the band because of family constraints. He was eventually replaced by ex-Soulfly drummer Roy Mayorga who played on all but two tracks on the album. Following the release of the album, Stone Sour promoted it for over a year, releasing five singles and touring in the United States, Canada, Japan and several countries in Europe. The album received generally positive reviews. It was praised for showing a progression in the band's songwriting ability and musical style. It was also certified Platinum in the United States and the single "30/30-150" was nominated for Best Metal Performance at the 49th Grammy Awards. On June 26, 2007, Stone Sour released a special edition version of the album; it included six previously unreleased tracks and a bonus DVD with three music videos and a complete live performance by the band in Moscow. It remains their best-selling album to date, mostly due to the success of the single "Through Glass". The album became their first to be certified Platinum by the RIAA which occurred on July 21, 2017.
"Quantitave Model of Solvent Effects on Hydroxypyridine-Pyridone and Mercaptopyridine-Thiopyridone Equilibria: Correlation with Reaction-Field and Hydrogen-Bond Effects". J. Org. Chem. 45 (8): 1347–1353. doi:10.1021/jo01296a001. Beak P, Covington JB, Smith SG, White JM, Zeigler JM (1980). "Displacement of Protomeric Equilibria by Self-Association: Hydroxypyridine-Pyridone and Mercaptopyridine-Thiopyridone Isomer Pairs". J. Org. Chem. 45 (8): 1354–1362. doi:10.1021/jo01296a002.
At the active site, a substrate binds to an enzyme to induce a chemical reaction. Substrates, transition states, and products can bind to the active site, as well as any competitive inhibitors. For example, in the context of protein function, the binding of calcium to troponin in muscle cells can induce a conformational change in troponin. This allows for tropomyosin to expose the actin-myosin binding site to which the myosin head binds to form a cross-bridge and induce a muscle contraction. In the context of the blood, an example of competitive binding is carbon monoxide which competes with oxygen for the active site on heme. Carbon monoxide's high affinity may outcompete oxygen in the presence of low oxygen concentration. In these circumstances, the binding of carbon monoxide induces a conformation change that discourages heme from binding to oxygen, resulting in carbon monoxide poisoning.
Pharmacodynamics (PD) is the core principle of quantifying the effects of antagonists by measuring the drug's efficacy and safety. PD emphasises the relationship between the dose and response of a certain drug, which can be illustrated using a dose-response curve. Efficacy is the maximal effect (Emax) that an agonist can produce. As a receptor antagonist does not affect receptors after binding, it is said to have zero efficacy. A competitive antagonist does not affect the Emax of the agonist. This is because the effect of an agonist can be maximized by adding the dose of the agonist as the action of the antagonist is reversible. The maximum effect of the agonist can be achieved by adding the concentration of the agonist. A non-competitive antagonist(or Allosteric antagonist) lowers the Emax of an agonist. The Emax of an agonist is inversely proportional to the concentration of the antagonist, which means a higher concentration of antagonist results in a lower Emax. The maximal efficacy of agonists is reduced as the inhibition cannot be reversed by adding the agonist concentration.
Sources: en.wikipedia.org
Tripartite motif-containing 24 (TRIM24) also known as transcriptional intermediary factor 1α (TIF1α) is a protein that, in humans, is encoded by the TRIM24 gene. The protein encoded by this gene mediates transcriptional control by interaction with the activation function 2 (AF2) region of several nuclear receptors, including the estrogen, retinoic acid, and vitamin D3 receptors. The protein localizes to nuclear bodies and is thought to associate with chromatin and heterochromatin-associated factors. The protein is a member of the tripartite motif (TRIM) family. The TRIM motif includes three zinc-binding domains – a RING, a B-box type 1 and a B-box type 2 – and a coiled-coil region. Two alternatively spliced transcript variants encoding different isoforms have been described for this gene. TRIM24 has been shown to interact with Mineralocorticoid receptor, TRIM33, Estrogen receptor alpha and Retinoid X receptor alpha. Transcription coregulator
37. Ugeskr Laeger. 2011 Mar 28;173(13):975. [Melanotan-induced lentigines and nevi]. [Article in Danish] Thestrup-Pedersen K(1), Søndergaard K. Author information: (1)Hudklinikken, 4800 Nykøbing Falster, Denmark. ktp56@hotmail.com A 25-year-old man had self-injected more than 150 doses of melanotan to increase his skin pigmentation, which had increased significantly. At the same time, his nevi had become darker and new nevi and lentigines developed; they also occurred on his genitals causing his referral. Two nevi were excised, but showed no signs of malignant transformation.
==== Distribution ==== Atomoxetine is well-distributed and its volume of distribution is 0.85 to 1.02 L/kg in CYP2D6 extensive metabolizers and 2.25 L/kg in CYP2D6 poor metabolizers, with its distribution being equivalent to total body water. Atomoxetine and its metabolites show only limited partitioning into red blood cells. Atomoxetine crosses the blood–brain barrier, with this appearing to be due primarily to passive diffusion rather than active transport. The drug is not a substrate of P-glycoprotein. Animal studies have found that atomoxetine and/or its metabolites can cross the placenta, but fetal exposure was substantially lower than maternal exposure. Similarly, only a small amount of atomoxetine and/or metabolites were excreted in milk in animals. Atomoxetine shows high plasma protein binding of 98.7% and is primarily bound to albumin and to a lesser extent to α1-acid glycoprotein and immunoglobulin G (IgG). Atomoxetine's limitedly active metabolite N-desmethylatomoxetine is 99.1% bound to plasma proteins, whereas its active metabolite 4-hydroxyatomoxetine shows plasma protein binding of 66.6%, which is substantially less than that of atomoxetine itself.
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.
No. Epithalamin is a heterogeneous peptide fraction obtained from pineal gland extract and contains many components. Epitalon is a single synthetic tetrapeptide with the sequence Ala-Glu-Asp-Gly. Researchers synthesised the shorter peptide while attempting to identify active sequences within the extract.