AEDG is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
Identity confirmation uses mass spectrometry, usually electrospray ionisation in positive mode or matrix-assisted laser desorption. The protonated free peptide produces a signal near three hundred and ninety-one daltons, while salt adducts shift that value slightly. Tandem mass spectrometry or amino acid analysis supplies sequence-level confirmation, which a single mass measurement cannot. Peptides containing aspartate can cyclise into succinimide intermediates that hydrolyse to isoaspartate isomers of identical mass. Because those isomers are difficult to separate chromatographically, identity and purity results carry more weight when interpreted together.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
| 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 tetrapeptide with the residue sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its monoisotopic mass is approximately 390.35 daltons, and it is usually supplied as a lyophilised trifluoroacetate or acetate salt. The compound was derived from a pineal gland extract called epithalamin, a heterogeneous preparation investigated in the former Soviet Union. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology described the tetrapeptide as a constituent fragment of that extract. Commercial material is offered as a laboratory reagent rather than as a finished pharmaceutical product.
Literature searches for this compound must account for several spelling variants. Indexing databases contain epitalon, epithalon, epithalone, and AEDG, and relevant records are scattered across Russian-language and English-language journals that do not consistently cross-cite. Early publications describe the parent extract as a mixture of many peptides, whereas later work addresses the single synthetic tetrapeptide. That shift in nomenclature complicates comparison between studies, because extract data and tetrapeptide data are sometimes cited interchangeably. A search strategy omitting the alternate spellings will return an incomplete set of references.
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.
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.
==== Conceptual history ==== In the two-part episodes "Colony" and "End Game", Chris Carter and Frank Spotnitz along with some help from David Duchovny created what would become a recurring character named the Alien Bounty Hunter. According to Carter, Duchovny came to him and said "wouldn't it be great if we had like an alien bounty hunter?" Carter was positive towards the idea and acted upon it. The actor Brian Thompson auditioned for the role in a casting session, where he was competing with another actor. Spotnitz and Carter did not have much time to cast this character, but they knew this casting would be important since they intended the character to become a recurring character. Thompson was chosen according to Spotnitz because he had a very "distinctive look" about him, most notably his face and mouth. After casting him, they told Thompson's agent that he needed a hair cut, because he was originally envisioned as a U.S. Air Force pilot who'd been shot down. When Thompson came to Vancouver, British Columbia, Canada there had been some "misunderstanding" between them, and he had not been told of the hair cut. So the hairstyle seen in this and every episode since was a "compromise" between Thompson and the producers.
A dough conditioner (also called a flour treatment agent, improving agent or bread improver) is any substance added to bread dough to strengthen its texture or otherwise improve it in some way. Dough conditioners may include enzymes, yeast nutrients, mineral salts, oxidants and reductants, bleaching agents and emulsifiers. Flour treatment agents are used to increase the speed of dough rising and to improve the strength and workability of the dough.
In the late 1920s, Pauling began publishing papers on the nature of the chemical bond. Between 1937 and 1938, he took a position as George Fischer Baker Non-Resident Lecturer in Chemistry at Cornell University. While at Cornell, he delivered a series of nineteen lectures and completed the bulk of his famous textbook The Nature of the Chemical Bond. It is based primarily on his work in this area that he received the Nobel Prize in Chemistry in 1954 "for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances". Pauling's book has been considered "chemistry's most influential book of this century and its effective bible". In the 30 years after its first edition was published in 1939, the book was cited more than 16,000 times. Even today, many modern scientific papers and articles in important journals cite this work, more than seventy years after the first publication. Part of Pauling's work on the nature of the chemical bond led to his introduction of the concept of orbital hybridization. While it is normal to think of the electrons in an atom as being described by orbitals of types such as s and p, it turns out that in describing the bonding in molecules, it is better to construct functions that partake of some of the properties of each.
Sources: en.wikipedia.org
She played a key role in the establishment of: • the Faculty of Public Health at the University of Debrecen (2005–2022), later integrated into the Faculty of Health Sciences; • the MTA–DE (later ELKH‑DE, then HUN‑REN‑DE) Public Health Research Group (2007–2022); • the WHO Collaborating Centre on Vulnerability and Health at the University of Debrecen (2012–2020); • the WHO Collaborating Centre on Healthy Ageing at Semmelweis University, jointly with Professor Zoltán Ungvári (2025–present); • the National Association of Public Health Training and Research Institutes (HAPHI), founded in 2007, of which she served as president until 2020 and is now honorary president. The international reputation of HAPHI is indicated by the fact, that in 2020 Róza Ádány as the founding president of HAPHI was awarded by the World Federation of Public Health Associations’ highest honour, the Hugh R. Leavell Award for exceptional contribution to improve population health globally. Under her leadership, Hungary developed a comprehensive public health education system covering the full training spectrum (undergraduate, graduate, postgraduate) training spectrum.
== In flow meters == An ultrasonic flow meter measures the velocity of a liquid or gas through a pipe using acoustic sensors. This has some advantages over other measurement techniques. The results are slightly affected by temperature, density or conductivity. Maintenance is inexpensive because there are no moving parts. Ultrasonic flow meters come in three different types: transmission (contrapropagating transit time) flowmeters, reflection (Doppler) flowmeters, and open-channel flowmeters. Transit time flowmeters work by measuring the time difference between an ultrasonic pulse sent in the flow direction and an ultrasound pulse sent opposite the flow direction. Doppler flowmeters measure the doppler shift resulting in reflecting an ultrasonic beam off either small particles in the fluid, air bubbles in the fluid, or the flowing fluid's turbulence. Open channel flow meters measure upstream levels in front of flumes or weirs. Optical time-of-flight sensors consist of two light beams projected into the fluid whose detection is either interrupted or instigated by the passage of small particles (which are assumed to be following the flow). This is not dissimilar from the optical beams used as safety devices in motorized garage doors or as triggers in alarm systems. The speed of the particles is calculated by knowing the spacing between the two beams. If there is only one detector, then the time difference can be measured via autocorrelation. If there are two detectors, one for each beam, then direction can also be known.
By the time the comparatively youthful Mikhail Gorbachev became General Secretary in 1985, the Soviet economy was stagnant and faced a sharp fall in foreign currency earnings as a result of the downward slide in oil prices in the 1980s. These issues prompted Gorbachev to investigate measures to revive the ailing state. An ineffectual start led to the conclusion that deeper structural changes were necessary, and in June 1987 Gorbachev announced an agenda of economic reform called perestroika, or restructuring. Perestroika relaxed the production quota system, allowed cooperative ownership of small businesses and paved the way for foreign investment. These measures were intended to redirect the country's resources from costly Cold War military commitments to more productive areas in the civilian sector. Despite initial skepticism in the West, the new Soviet leader proved to be committed to reversing the Soviet Union's deteriorating economic condition instead of continuing the arms race with the West. Partly as a way to fight off internal opposition from party cliques to his reforms, Gorbachev simultaneously introduced glasnost, or openness, which increased freedom of the press and the transparency of state institutions. Glasnost was intended to reduce the corruption at the top of the Communist Party and moderate the abuse of power in the Central Committee. Glasnost also enabled increased contact between Soviet citizens and the Western world, particularly with the United States, contributing to the accelerating détente between the two nations.
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.
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.