Everything below concerns lyophilised powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-12. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Identity and purity are established with reversed-phase high-performance liquid chromatography and mass spectrometry. The chromatogram shows the main peak and any truncated or oxidised by-products, while the mass spectrum confirms the expected 390 dalton mass. Amino acid analysis can corroborate composition when a sample's origin is uncertain. Counterion content, particularly residual trifluoroacetate from purification, is frequently reported alongside purity because it shifts the net mass of the solid.
Reference material is normally supplied as a lyophilised powder in a sealed vial. Product literature typically recommends storage at minus twenty degrees Celsius or colder, protected from light and moisture. Freeze-thaw cycling is usually avoided because repeated condensation can introduce water into the vial. Working solutions are commonly prepared fresh, aliquoted, and kept cold for short periods rather than stored at ambient temperature. Labelling the date of opening helps track how long a vial has been in use.
Solubility is high in water, phosphate-buffered saline and normal saline, a pattern that follows from the two acidic residues in the chain. The peptide dissolves poorly in non-polar solvents such as hexane or chloroform. Stock solutions are often prepared in water first and then diluted into the buffer of interest. Because the molecule is small and hydrophilic, filtration through a low-protein-binding membrane is usually straightforward, and visible particulates are uncommon in freshly made solutions.
| 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 |
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
Epitalon is a synthetic four-amino-acid peptide with the sequence alanine-glutamate-aspartate-glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9, and its calculated molar mass is approximately 390.35 grams per mole. The compound is a short fragment related to a peptide fraction isolated from bovine pineal gland extracts, and it is normally supplied as a lyophilised powder intended for laboratory research. It is not a registered pharmaceutical product in most countries.
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.
==== Racemate separation ==== Since only one of the stereoisomers has the desired effect, the separation of a racemic mixture of hydroxy N- methyl morphinan using tartaric acid and subsequent methylation of the hydroxyl group is a suitable method. By using (D)-tartrate, the (+)-isomer remains as the product.
It may be an advantage to know that a man can travel 520 miles in 138 hours, and manage to live through a week with an infinitesimal amount of rest, though we fail to perceive that anyone could possibly be placed in a position where his ability in this respect would be of any use to him [and] what is to be gained by a constant repetition of the fact. The event proved popular, however, with 20,000 spectators attending each day. Encouraged, the promoters developed the idea and soon held similar races for cyclists.
This is an energy dependent process that becomes more energetically unfavorable for the yeast cell as fermentation progressed and ethanol levels increase, creating "passive leakage" of excess hydrogen ions into the cell. The cell's hydrogen ion pumps have to work even harder to maintain its internal pH so it sends a signal to the symport proteins to stop bringing other ions. This is one of the reasons why late fermentation nitrogen additions have little to no effective as the transport mechanisms of the nitrogen into the cell are shut down.
{\displaystyle {\boldsymbol {\sigma }}=-p\mathbf {I} +\mu \left(\nabla \mathbf {u} +(\nabla \mathbf {u} )^{\mathrm {T} }\right)+\left(\zeta -{\frac {2}{3}}\mu \right)(\nabla \cdot \mathbf {u} )\mathbf {I} .}
The blue mackerel is found in tropical to subtropical waters of the Indian and Pacific Oceans. In the Indo-West Pacific, there is a population in the Red Sea and western Arabian Sea, one in the Northwest Pacific (Japan, China, and Taiwan), and another one in the Southwest Pacific (Australia and New Zealand). Furthermore, the blue mackerel also occur in the eastern Pacific (Hawaii and Revillagigedo Islands, Mexico). It occurs in surface waters down to 300 m (980 ft).
Sources: en.wikipedia.org
AMP has a much stronger affinity for the binding domain (known as the Bateman domain) of AMPK, and will thus out-compete ATP as AMP concentration increases. This ultimately results in the phosphorylation and activation of AMPK by LKB1 and triggers a cascade of signaling events driven by AMPK, leading to the translocation of GLUT4. Muscle stretching also stimulates GLUT4 translocation and glucose uptake in rodent muscle via RAC1.
Workers exposed to high air levels of copper (resulting in an estimated intake of 200 mg Cu/d) developed signs suggesting copper toxicity (e.g., elevated serum copper levels, hepatomegaly). However, other co-occurring exposures to pesticidal agents or in mining and smelting may contribute to these effects. Effects of copper inhalation are being thoroughly investigated by an industry-sponsored program on workplace air and worker safety. This multi-year research effort is expected to be finalized in 2011.
==== Renewed clashes ==== The conflict between Houthis and Salafis in Saada Governorate was renewed in October and November. Saada government officials accused Houthi fighters of attacking a Salafi mosque in Dammaj in an attempt to drive the Sunnis out, while the Houthis accused the Salafis of using the religious institute as a staging ground for foreign Sunni fighters. The government attempted to intervene to stop the fighting. Sectarian fighting in Al Jawf Governorate lasted throughout the year. Dhamar Governorate also saw clashes between the Houthis and Salafis toward the end of the year.
=== Fertilizers === Metal chelate compounds are common components of fertilizers to provide micronutrients. These micronutrients (manganese, iron, zinc, copper) are required for the health of the plants. Most fertilizers contain phosphate salts that, in the absence of chelating agents, typically convert these metal ions into insoluble solids that are of no nutritional value to the plants. EDTA is the typical chelating agent that keeps these metal ions in a soluble form.
Sources: en.wikipedia.org
BCN, also known as bicyclo[6.1.0]non-4-yne, is a copper-free click chemistry probe that enables highly efficient and completely orthogonal bioconjugation to complex macromolecules including peptides, nucleic acids and proteins, including monoclonal antibodies. The most recent and powerful application of this technology has been in the field of antibody-drug conjugates which results in targeted cancer therapeutics that have an improved therapeutic index, meaning they are more effective and better tolerated. BCN is well-suited for aqueous bioconjugations due to its high reactivity with its azide counterpart and its high hydrophilicity, relative to other metal-free click chemistry probes.
On March 21, 2018, Starbucks announced that it was considering the use of blockchain technology to connect coffee drinkers with coffee farmers who could eventually be able to take advantage of new financial opportunities. The pilot program was planned to start with farmers in Costa Rica, Colombia, and Rwanda in order to develop a new way to track the bean-to-cup journey. In 2019, at the Microsoft Build conference, the coffee company formally announced its "bean to cup" program using the Microsoft's Azure-based blockchain service. Two men were arrested in a Philadelphia Starbucks location after a manager claimed the two were trespassing on April 12, 2018. The arrests led to protests due to their apparently racially motivated nature. CEO Kevin Johnson later apologized for the incident, and the company declined to press charges. During the company's second quarter earnings call on April 26, Johnson indicated that the company had not seen a drop in sales as a result of the event and subsequent coverage. The company reiterated its guidance for full year earnings, and beat consensus expectations of 1.8 percent same-store sales growth, with 2 percent growth. Johnson announced that the company would close some 8000 locations on May 29 for a seminar about racial bias in order to prevent future events similar to those that occurred in Philadelphia. On June 19, 2018, Starbucks announced the closing of 150 locations in 2019, three times the number the corporation typically closes in a single year. The closings were to happen in urban areas that already have dense clusters of stores.
== Distribution == Lutzner cells begin developing in bone marrow then travel to the thymus via the secretion of the hormone thymosin. The secretion allows them to differentiate and mature. Once the mutated cell is developed, it patiently waits in the thymus until an antigen presents itself. When a cutaneous lymphocyte antigen is expressed in the skin, the CD4+ Lutzner cell travels to the epidermis and dermis layers of the skin in order to bind to the antigen.
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.
Sealed lyophilised powder is normally kept at minus twenty degrees Celsius or below, away from light and moisture. Vials are allowed to reach room temperature before opening to limit condensation. Repeated warming and cooling of the same vial is discouraged.