This is a working overview of Tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-11 and is reviewed periodically as new material appears.
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.
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.
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.
（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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Synthetic tetrapeptide, four residues |
| Nominal mass | Approximately 390 Da | Free peptide; salt forms differ |
| Appearance | White to off-white powder | Commonly supplied lyophilised |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffer |
| Typical storage | −20 °C, desiccated | Cold packs used during transport |
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.
Laboratory work has examined effects on telomerase activity in cultured cells, on melatonin rhythms in animals, and on markers of oxidative stress. Some experiments report measurable changes while others show none, and the reported findings rest largely on small studies. The absence of large independent trials means the generality of these results is unresolved rather than settled. Review articles occasionally apply the label geroprotector, a term that reflects a research hypothesis about ageing rather than an established clinical finding.
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.
== Pathology == While most cells require the action of insulin for glucose to gain entry into the cell, the cells of the retina, kidney, and nervous tissues are insulin-independent, so glucose moves freely across the cell membrane, regardless of the action of insulin. The cells will use glucose for energy as normal, and any glucose not used for energy will enter the polyol pathway. When blood glucose is normal (about 100 mg/dL or 5.5 mmol/L), this interchange causes no problems, as aldose reductase has a low affinity for glucose at normal concentrations. In a hyperglycemic state, the affinity of aldose reductase for glucose rises, causing much sorbitol to accumulate, and using much more NADPH, leaving less NADPH for other processes of cellular metabolism. This change of affinity is what is meant by activation of the pathway. The amount of sorbitol that accumulates, however, may not be sufficient to cause osmotic influx of water. NADPH acts to promote nitric oxide production and glutathione reduction, and its deficiency will cause glutathione deficiency. A glutathione deficiency, congenital or acquired, can lead to hemolysis caused by oxidative stress. Nitric oxide is one of the important vasodilators in blood vessels. Therefore, NADPH prevents reactive oxygen species from accumulating and damaging cells. Excessive activation of the polyol pathway increases intracellular and extracellular sorbitol concentrations, increased concentrations of reactive oxygen species, and decreased concentrations of nitric oxide and glutathione.
==== Non-soluble or undissolvable MNPs ==== Other than dissolvable MNPs, needles can also be made out of metal or ceramic that will not dissolve in the body environment. These coated drug needles can deliver consistent concentration of drugs without the needles dissolving in the body. This kind of MNPs has better performance, but compared to the soluble MNPs, metal or ceramic MNPs are the older version of MNPs. Even if the patches are small, the metal or ceramic MNPs may cause several waste issues. Recycling the metal and ceramic are very hard, as the quantity is very small to overcome the cost to recycle. That is why researchers try to develop the dissolvable MNPs with similar characteristic and performance of drug delivery in non-soluble MNPs.
A lack of economy of size: as most fine chemicals are produced in quantities of less than a few 10 tons per year in multipurpose plants, there is little or no economy of size. The reactor trains of these plants are similar throughout the industry. Regardless of the size of the companies, their main constituents, the reaction vessels, have a median size of 4–6 m3 (140–210 cubic feet). Various products are made throughout a year in campaigns. Therefore, the unit cost per m3 per hour rarely varies with the size of the company. A dichotomy between ownership and management: the company's shares are listed on stock exchanges, and their performance is scrutinized by the financial community. Postponement of a single important shipment can affect a quarterly result. In the small and mid-sized companies, the owners are typically the major shareholders, often members of the same family. Their shares are not traded publicly and fluctuations in their financial performance are more easily coped with. Complicated business processes: flexibility and responsiveness are in jeopardy. Customer complaints, for instance, are difficult to resolve in a straightforward manner. A heterogeneous portfolio of small companies, accumulated over time through M&A activities. The key functions, such as production, R&D, and M&S, are located on different sites, often in different countries. Cohabitation with other units. A comprehensive list of about 1400 fine chemical companies (including traders) can be found in the "event catalogue" of the CPhI exhibition.
=== Calcium hydroxylapatite === Marketed as "Coaptite", this is spherical particles of calcium hydroxylapatite ceramic suspended in a sodium carboxylmethylcellulose, glycerine and water carrier gel. This is a synthetic version of a compound that is a normal component of bones and teeth. It is non-antigenic and noninflammatory. The particle size is in the range 75–125 μm and therefore should avoid migration away from the implant site. Once in place, the particles are enmeshed in a non-encapsulated stable soft collagen matrix. This matrix maintains volume even after the solid particles have been degraded and resorbed. The material is radio-opaque (and therefore will be visible on x-rays). It has been used in dental and orthopedic reconstructive surgery, and for replacement heart valves. In the field of plastic surgery, it is termed Radiance FNTM. As of 2022 only one publication exists. The material was used in submucosal injection site via transsphincteric route.
Sources: en.wikipedia.org
== Biochemistry == Pyruvate is important in biochemistry. It is the output of the metabolism of glucose known as glycolysis. One molecule of glucose breaks down into two molecules of pyruvate, which are then used to provide further energy, in one of two ways. Pyruvate is converted into acetyl-coenzyme A, which is the main input for a series of reactions known as the Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle). Pyruvate is also converted to oxaloacetate by an anaplerotic reaction, which replenishes Krebs cycle intermediates; also, the oxaloacetate is used for gluconeogenesis. These reactions are named after Hans Adolf Krebs, the biochemist awarded the 1953 Nobel Prize for physiology, jointly with Fritz Lipmann, for research into metabolic processes. The cycle is also known as the citric acid cycle or tricarboxylic acid cycle, because citric acid is one of the intermediate compounds formed during the reactions. If insufficient oxygen is available, the acid is broken down anaerobically, creating lactate in animals and ethanol in plants and microorganisms (and in carp). Pyruvate from glycolysis is converted by fermentation to lactate using the enzyme lactate dehydrogenase and the coenzyme NADH in lactate fermentation, or to acetaldehyde (with the enzyme pyruvate decarboxylase) and then to ethanol in alcoholic fermentation. Pyruvate is a key intersection in the network of metabolic pathways. Pyruvate can be converted into carbohydrates via gluconeogenesis, to fatty acids or energy through acetyl-CoA, to the amino acid alanine, and to ethanol.
== Pregnancy == In studies with rats and rabbits treated chronically, Oprelvekin showed embryo- and fetotoxicity (early death of embryos and reduction of number of fetus, fetal malformations etc.). There is no sufficient human data available. Pregnant women should only be treated, if the benefit to the mother outweighs the potential risk to the unborn.
=== Pre-1970 jury trials === Before they were abolished in 1970, jury trials were conducted to hear capital cases in Singapore since the British colonial era. Based on the verdict of a jury, if a person was found guilty, the judge would convict and impose a penalty to the defendant in accordance to the charge he or she was found guilty of. One notable case in which a person was sentenced to death in a jury trial was the trial of Sunny Ang Soo Suan, who allegedly murdered his girlfriend Jenny Cheok Cheng Kid during a scuba diving trip in 1963. Despite the circumstantial evidence and the absence of the victim's body, the seven-men jury unanimously found Ang guilty of murder and sentenced him to death. Ang was eventually hanged on 6 February 1967 after he lost all his appeals to both the Court of Appeal and the Privy Council, and the failure of his clemency plea to President Yusof Ishak. The first person to be tried before two judges in the High Court and sentenced to death for a capital case was armed robber Teo Cheng Leong, who was found guilty and sentenced in February 1970 for unlawfully discharging a firearm twice when he fired two missed shots at a police officer. Another notable case was the kidnapping and murder of Ong Beang Leck, the son of a rich tycoon. Five men were involved in the abduction and they had murdered Ong after luring him into a rented car on 24 May 1968. Three of the kidnappers were found guilty of murder and sentenced to death in June 1970.
All boards of certification now require that medical practitioners demonstrate, by examination, continuing mastery of the core knowledge and skills for a chosen specialty. Recertification varies by particular specialty between every seven and every ten years. In the United States there are hierarchies of medical specialties in the cities of a region. Small towns and cities have primary care, middle sized cities offer secondary care, and metropolitan cities have tertiary care. Income, size of population, population demographics, distance to the doctor, all influence the numbers and kinds of specialists and physicians located in a city.
RSNa + R'COCl → R'COSR + NaCl Another common route entails the displacement of halides by the alkali metal salt of a thiocarboxylic acid. (The analogous alkylation of a carboxylate salt is rarely practiced.) For example, thioacetate esters are commonly prepared by alkylation of potassium thioacetate:
Sources: en.wikipedia.org
=== Withdrawal === Discontinuation of baclofen can be associated with a withdrawal syndrome which resembles barbiturate, benzodiazepine withdrawal and alcohol withdrawal. Withdrawal symptoms are more likely if baclofen is administered intrathecally or for long periods of time (more than a couple of months) and can occur from low or high doses. The severity of baclofen withdrawal depends on the rate at which it is discontinued. Thus to minimise withdrawal symptoms, the dose should be tapered down slowly when discontinuing baclofen therapy. Abrupt withdrawal is more likely to result in severe withdrawal symptoms. Acute withdrawal symptoms can be eased or completely reversed by re-initiating therapy with baclofen. Withdrawal symptoms may include auditory hallucinations, visual hallucinations, tactile hallucinations, delusions, confusion, agitation, delirium, disorientation, fluctuation of consciousness, insomnia, dizziness, nausea, inattention, memory impairments, perceptual disturbances, itching, anxiety, depersonalization, hypertonia, hyperthermia (higher than normal temperature without infection), formal thought disorder, psychosis, mania, mood disturbances, restlessness, and behavioral disturbances, tachycardia, seizures, tremors, autonomic dysfunction, hyperpyrexia (fever), extreme muscle rigidity resembling neuroleptic malignant syndrome and rebound spasticity.
Because prokaryotic mRNA does not need to be processed or transported, translation by the ribosome can begin immediately after the end of transcription. Therefore, it can be said that prokaryotic translation is coupled to transcription and occurs co-transcriptionally. In eukaryotic cells the process of translation starts with the information stored in the nucleotide sequence of DNA. This is first transformed into mRNA, then transfer RNA (tRNA) specifies which three-nucleotide codon from the genetic code corresponds to which amino acid. Eukaryotic mRNA that has been processed and transported to the cytoplasm (i.e., mature mRNA) can then be translated by ribosomes. Translation may occur at ribosomes free in the cytoplasm, or targeted to the endoplasmic reticulum by the signal recognition particle. Therefore, unlike in prokaryotes, eukaryotic translation is not directly coupled to transcription. In some contexts, protein abundance can increase even when mRNA abundance decreases, because translation efficiency and protein turnover are regulated independently of transcript levels; this has been reported for mRNA and protein levels of EEF1A1 in breast cancer.
is a quotient of activity coefficients. To avoid the complications involved in using activities, dissociation constants are determined, where possible, in a medium of high ionic strength, that is, under conditions in which
Mister Donut has an orange and white logo in the likeness of a moustachioed chef. More recently, the chain developed a set of mascot characters based on its donuts. One character, "Pon de Lion" (ポン・デ・ライオン, Pon De Raion), a lion with a mane shaped like its "pon de ring" (ポン・デ・リング, Pon De Ringu) donut line, is used in Japan. In El Salvador, the mascots are five anthropomorphic doughnuts and a rooster that is used for the breakfast menu. The company uses the same logo as Japan, and the slogan is "La gran variedad" (The great variety).
== Chemistry == 2C-B, also known as 4-bromo-2,5-dimethoxyphenethylamine, is a substituted phenethylamine of the 2C family, also known as the 4-substituted 2,5-dimethoxyphenethylamines. It is a synthetic analogue of the naturally occurring phenethylamine psychedelic mescaline found in peyote and certain other cacti.
Sources: en.wikipedia.org
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.
No endogenous peptide with this exact sequence has been described as a circulating hormone or signalling molecule. The tetrapeptide was designed as a synthetic analogue based on fragments observed in pineal preparations. Any activity discussed in the literature therefore refers to administered material rather than to a natural pool of the compound.
It is not an approved medicine in major jurisdictions and does not appear in the major pharmacopoeias. Material is usually distributed as a research chemical or laboratory reagent. Such labelling places handling responsibility on the purchaser and does not indicate that a regulatory body has reviewed the substance.
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.