The short version of AEDG fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-02-01. 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.
Reported biological findings come mainly from cell culture and rodent experiments. Those studies describe changes in telomerase catalytic subunit expression, melatonin rhythm amplitude, and antioxidant enzyme activity after peptide exposure. Human data are sparse and consist of small trials with limited blinding and inconsistent endpoints. The proposed mechanisms remain hypotheses rather than established facts, and there is no consensus on whether effects observed in animals carry over to people. Independent replication outside the original research groups is limited, which is a recognised gap in the published literature.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
| 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 |
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage recommendations center on limiting moisture, heat, and light. The dry powder is generally kept at minus 20 degrees Celsius, and some suppliers recommend minus 80 degrees for long-term archival. Once dissolved, solutions are usually aliquoted and frozen to avoid repeated freeze-thaw cycles, which can promote aggregation or degradation. Aqueous stability depends on pH and concentration, and buffered saline is often preferred over plain water for biological work. Stability data specific to epitalon remain limited, so general peptide-handling practices are applied by analogy rather than from product-specific validation.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
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.
Algicidal bacteria are a diverse group of bacteria that either directly or indirectly inhibit the growth of algae. They play a key role in maintaining ecological stability in fresh water and marine environments by mitigating the negative effects of harmful algal blooms (HAB). Algicidal bacteria interactions with algal cells can be broadly split into two categories: direct and indirect. Direct methods typically involve the algicidal bacteria physically attacking the algal cell to induce cell lysis. Indirect methods of attack by algicidal bacteria typically involve releasing algae inhibiting chemicals into the surrounding water. Algicidal bacteria can detect targeted algal cells via chemotaxis and quorum sensing. Different species of algicidal bacteria can have varying degrees of specificity and many have co-evolved along their target algae. Algicidal bacteria have been used as a biological control method against HABs. They tend to be more environmentally friendly than traditional algicides.
===== History of Vitatron ===== 1956: Vitatron founded 1962: First Implantable pacemakers 1981: Microprocessor-driven, software-based pacemaker (DPG1) 1982: Rate Responsive pacemaker (TX1) 1984: Quintech DDD with automatic upper rate behavior ("mode switch") 1988: Daily Learn algorithm (Rhythmyx) 1997: First upgradeable pacemaker system with dedicated AF diagnostics, rate and rhythm control therapy. 2003: Vitatron goes digital: 1st Vitatron C-Series, the world's first fully digital pacemaker. 2004: 2nd Vitatron C-Series, digital, fast pacemaker. 2004: Vitatron T-Series: The full picture, digital pacemaker system. 2005: Vitatron C-Series, A3 models, a new top line range of digital pacemakers for bradycardic patients.
Since 1999, some countries have legalized prostitution, such as Germany (2002) and New Zealand (2003). However, in most countries the practice is prohibited. Gathering accurate statistics on prostitution and human trafficking is extremely difficult. This has resulted in proponents of legalization claiming that it reduces organized crime rates while opponents claim exactly the converse. The Dutch prostitution policy, which is one of the most liberal in the world, has gone back and forth on the issue several times. In the period leading up to 2015 up to a third of officially sanctioned work places had been closed down again after reports of human trafficking. Prostitutes themselves are generally opposed to what they see as "theft of their livelihood". Legal prostitution means prostitutes can contact police in instances of abuse or violence without fear of arrest or prosecution because of what they are doing being illegal. A legal and regulated system can also provide licensed brothels as opposed to prostitutes working on the streets, in which the owners or staff of the premises can call the police in instances of violence against sex workers without fear of workers or the business facing criminal charges or being shut down. Legal and regulated prostitution can require prostitutes to undergo regular health checks for sexually transmitted infections (STIs) by law. Sex workers in Nevada for instance have to get monthly tests for syphilis and HIV and weekly tests for gonorrhea and chlamydia.
== Medical application == S. helianthus shows a variety of promising applications in the medical field due to its toxin-producing capability. ShK-186, a peptide inhibitor, is a toxin that has been previously implemented in clinical trials for its potential treatment of autoimmune diseases. It has been further developed into an “investigational drug”, known as Dalazatide, in which it targets the disease-causing cells corresponding to ailments including type 1 diabetes, lupus erythematosus and multiple sclerosis. The aforementioned cytolysins, St I and St II, have also shown pharmacological potential in studies with guinea pig models, with direct implications on neural and cardiac activity. Due to its capability of protease inhibition, ShPI-1 is another toxin with medical potential. This toxin is a “non-specific inhibitor” and provides a variant with “increased biomedical potential” for its inhibition properties. Though many of these toxins require further research, S. helianthus serves great potential in biomedical applications for toxin production.
In some part of South China, soups (Chinese: 湯/汤 tāng) are served between the cold dishes and the main dishes. In other parts of China, soups are served between the main dish and staple foods, before desserts or fruit salad. There are many traditional Chinese soups, such as wonton soup, herbal chicken soup, hot and sour soup, winter melon soup, and so on.
Sources: en.wikipedia.org
=== Kröhnke pyridine synthesis === In the Kröhnke pyridine synthesis, an N-pyridine-substituted methyl ketone is used as the reactant. This compound enters the keto-enol equilibrium and reacts with an enone via a Michael addition. A 1,5-dicarbonyl compound is formed, one carbonyl group of which is replaced by ammonia (or a synthesis equivalent) to form an imine. This intermediate subsequently cyclizes to give a pyridine. The reaction is named after Fritz Kröhnke, who developed it for the preparation of 2,4,6-triarylpyridines and published it in 1961.
=== Legal status === Levomethadone is listed under the Single Convention On Narcotic Drugs 1961 and is a Schedule II Narcotic controlled substance in the US as an isomer of methadone (ACSCN 9250) and is not listed separately, nor is dextromethadone. It is similarly controlled under the German Betäubungsmittelgesetz and similar laws in practically every other country.
== Chemistry == KNX-100 is a synthetic small molecule and peptide fragment of the oxytocin system. Its chemical structure has been disclosed by its developers in a patent. The chemical synthesis of KNX-100 has been described. The small-molecule oxytocin receptor agonists LIT-001 and LIT-002 are derivatives of KNX-100. The more-compact small-molecule oxytocin receptor agonists WJ0679 and CA7 are also analogues of KNX-100.
Peptide signaling plays a significant role in various aspects of plant growth and development and specific receptors for various peptides have been identified as being membrane-localized receptor kinases, the largest family of receptor-like molecules in plants. Signaling peptides include members of the following protein families.
Sources: en.wikipedia.org
The delay in effectiveness of the incapacitation mechanism is believed to be a protective mechanism that prevents a male fly from incapacitating his own sperm should he mate with the same female fly repetitively. Sensory neurons in the uterus of female D. melanogaster respond to a male protein, sex peptide, which is found in semen. This protein makes the female reluctant to copulate for about 10 days after insemination. The signal pathway leading to this change in behavior has been determined. The signal is sent to a brain region that is a homolog of the hypothalamus and the hypothalamus then controls sexual behavior and desire. Gonadotropic hormones in Drosophila maintain homeostasis and govern reproductive output via a cyclic interrelationship, not unlike the mammalian estrous cycle. Sex peptide perturbs this homeostasis and dramatically shifts the endocrine state of the female by inciting juvenile hormone synthesis in the corpus allatum. D. melanogaster is often used for life extension studies, such as to identify genes purported to increase lifespan when mutated. D. melanogaster is also used in studies of aging. Werner syndrome is a condition in humans characterized by accelerated aging. It is caused by mutations in the gene WRN that encodes a protein with essential roles in repair of DNA damage. Mutations in the D. melanogaster homolog of WRN also cause increased physiologic signs of aging, such as shorter lifespan, higher tumor incidence, muscle degeneration, reduced climbing ability, altered behavior and reduced locomotor activity.
Eliminative cleavage of (1→4)-α-D-galacturonan to give oligosaccharides with 4-deoxy-α-D-galact-4-enuronosyl groups at their non-reducing ends The structure and the folding kinetics of one member of this family, pectate lyase C (pelC)1 from Erwinia chrysanthemi has been investigated in some detail,. PelC contains a parallel beta-helix folding motif. The majority of the regular secondary structure is composed of parallel beta-sheets (about 30%). The individual strands of the sheets are connected by unordered loops of varying length. The backbone is then formed by a large helix composed of beta-sheets. There are two disulphide bonds in PelC and 12 proline residues. One of these prolines, Pro220, is involved in a cis peptide bond. The folding mechanism of PelC involves two slow phases that have been attributed to proline isomerization. Some of the proteins in this family are allergens. Allergies are hypersensitivity reactions of the immune system to specific substances called allergens (such as pollen, synthetic materials, dust, stings, drugs, or food) that, in most people, result in no symptoms. A nomenclature system has been established for antigens (allergens) that cause IgE-mediated atopic allergies in humans. This nomenclature system is defined by a designation that is composed of the first three letters of the genus; a space; the first letter of the species name; a space and an Arabic number. In the event that two species names have identical designations, they are discriminated from one another by adding one or more letters (as necessary) to each species designation.
Neurotransmitter receptors and receptor ionophores. Nicotinic, imidazoline I1 and I2, α2-adrenergic, glutamate NMDAr, and serotonin 5-HT2A and 5HT-3 receptors. Ion channels. Including: ATP-sensitive K+ channels, voltage-gated Ca2+ channels, and acid-sensing ion channels (ASICs). Membrane transporters. Agmatine specific-selective uptake sites, organic cation transporters (mostly OCT2 subtype), extraneuronal monoamine transporters (ENT), polyamine transporters, and mitochondrial agmatine specific-selective transport system. Nitric oxide (NO) synthesis modulation. Both differential inhibition and activation of NO synthase (NOS) isoforms is reported. Polyamine metabolism. Agmatine is a precursor for polyamine synthesis, competitive inhibitor of polyamine transport, inducer of spermidine/spermine acetyltransferase (SSAT), and inducer of antizyme. Protein ADP-ribosylation. Inhibition of protein arginine ADP-ribosylation. Matrix metalloproteases (MMPs). Indirect down-regulation of the enzymes MMP 2 and 9. Advanced glycation end product (AGE) formation. Direct blockade of AGEs formation. NADPH oxidase. Activation of the enzyme leading to H2O2 production.
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.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.