tetrapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-02-22 and is reviewed periodically as new material appears.
The four residues give epitalon a molecular formula of C14H22N4O9 and a molecular weight near 390.35 daltons. The presence of two acidic residues, glutamate and aspartate, makes the free peptide strongly acidic, while the alanine and glycine ends provide neutral, nonpolar character. This combination produces a molecule with substantial water solubility. Because there are no cysteine, methionine, or tryptophan residues, the peptide lacks the most common oxidation-sensitive side chains, which simplifies handling compared with many longer peptides.
The proposed relationship between epitalon and pineal function is a central part of its background. Khavinson's group reported that short peptides corresponding to regions of larger pineal proteins could influence gene expression in cells. Epitalon was framed as a synthetic analogue of an active fragment rather than a direct isolation product. Whether the tetrapeptide reproduces the effects of the parent extract is an open question, because comparative studies are limited and the parent extract itself is not a single defined substance.
Interest in epitalon is usually discussed within the broader field of short peptide bioregulators, a category that includes other synthetic di-, tri-, and tetrapeptides studied by the same research group. These compounds share a common rationale: that small fragments of tissue-derived proteins can retain biological activity and can be produced reproducibly. The category as a whole remains outside mainstream pharmacological consensus, and epitalon specifically has a limited presence in independent, non-Russian research literature, which shapes how its evidence base is described.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
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.
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.
Laboratory handling begins with dissolution of the lyophilized powder in water or a suitable aqueous buffer. The dry solid is the more stable form, so stock solutions are generally prepared only when required and kept cold afterwards. Repeated freezing and thawing of a solution is avoided because it encourages aggregation and gradual loss of the intact chain. Diluents and containers are selected to limit adsorption of a short peptide onto plastic surfaces and to reduce microbial growth in aqueous preparations.
Stability depends strongly on pH, temperature and the presence of oxygen and trace metals. Cleavage of the backbone proceeds faster under neutral to alkaline conditions, whereas acidic solutions tend to slow that reaction. The aspartate and glutamate side chains can undergo deamidation or imide formation over time, generating closely related impurities. Published stability data specific to epitalon are sparse, so the usable life of a given solution is best regarded as an open question that depends on buffer composition, concentration and storage temperature.
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.
=== Soft nanoparticles === Most soft nanoparticles have core–shell structures. The semiflexible surface ligands soften the interaction of the cores and create a more spherical shape than the underlying core from uniform coverage. The surface ligands can be chosen from surfactants, polymers, DNA, ions, etc. Tuning the structure of superlattices can be achieved by varying the amount of surface ligands. Their "soft" behavior results in different self-assembly rules from hard particles, where Pauling's rules expired. To tailor the superlattice structure of soft nanoparticles, six design rules of spherical nanoparticle superlattice are established based on the study of metal–DNA nanoparticles:
Cathelicidin antimicrobial peptide (CAMP) is an antimicrobial peptide encoded in the human by the CAMP gene. The active form is LL-37, a 37 amino acid peptide having sequence LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES. In humans, CAMP encodes the peptide precursor CAP-18 (18 kDa), which is processed by proteinase 3-mediated extracellular cleavage into the active form LL-37. The cathelicidin family includes 30 types of which LL-37 is the only cathelicidin in the human. Cathelicidins are stored in the secretory granules of neutrophils and macrophages and can be released following activation by leukocytes. Cathelicidin peptides are dual-natured molecules called amphiphiles: one end of the molecule is attracted to water and repelled by fats and proteins, and the other end is attracted to fat and proteins and repelled by water. Members of this family react to pathogens by disintegrating, damaging, or puncturing cell membranes. Cathelicidins thus serve a critical role in mammalian innate immune defense against invasive bacterial infection. The cathelicidin family of peptides are classified as antimicrobial peptides (AMPs). The AMP family also includes the defensins. Whilst the defensins share common structural features, cathelicidin-related peptides are highly heterogeneous. Members of the cathelicidin family of antimicrobial polypeptides are characterized by a highly conserved region (cathelin domain) and a highly variable cathelicidin peptide domain. Cathelicidin peptides have been isolated from many different species of mammals, including marsupials.
==== Fe2+/α-ketoglutarate-dependent dioxygenase enzymes and TET enzymes ==== α-Ketoglutarate is a cofactor that activates histone-lysine demethylase protein superfamily. This superfamily consists of two groups, the FAD-dependent amine oxidases which do not require α-ketoglutarate for activation and the Fe2+/α-ketoglutarate-dependent dioxygenases (Fe2+ is the ferrous form of iron, i.e., Fe2+). The latter group of more than 30 enzymes is classified into 7 subfamilies termed histone lysine demethylases, i.e., HDM2 to HDM7, with each subfamily having multiple members. These HDMs are characterized by containing a Jumonji C (JmjC) protein domain. They function as dioxygenases or hydroxylases to remove methyl groups from the lysine residues on the histones enveloping DNA and thereby alter the expression of diverse genes. These altered gene expressions lead to a wide range of changes in the functions of various cell types and thereby caused the development and/or progression of various cancers, pathological inflammations, and other disorders (see α-Ketoglutarate-dependent demethylase biological functions). The TET enzymes (i.e., ten-eleven translocation (TET) methylcytosine dioxygenase family of enzymes) consists of three members, TET-1, TET-2, and TET-3. Like the Fe2+/α-ketoglutarate-dependent dioxygenases, all three TET enzymes require Fe2+ and α-ketoglutarate as cofactors to become activated. Unlike the dioxygenases, however, they remove methyl groups from the 5-methylcytosines of DNA sites that regulate the expression of nearby genes.
Sources: en.wikipedia.org
=== Aquatic environments === Most PAHs are insoluble in water, which limits their mobility in the environment, although PAHs sorb to fine-grained organic-rich sediments. Aqueous solubility of PAHs decreases approximately logarithmically as molecular mass increases. Two-ringed PAHs, and to a lesser extent three-ringed PAHs, dissolve in water, making them more available for biological uptake and degradation. Further, two- to four-ringed PAHs volatilize sufficiently to appear in the atmosphere predominantly in gaseous form, although the physical state of four-ring PAHs can depend on temperature. In contrast, compounds with five or more rings have low solubility in water and low volatility; they are therefore predominantly in solid state, bound to particulate air pollution, soils, or sediments. In solid state, these compounds are less accessible for biological uptake or degradation, increasing their persistence in the environment.
== Music == The origins of music during the Paleolithic are unknown. The earliest forms of music probably did not use musical instruments other than the human voice or natural objects such as rocks. This early music would not have left an archaeological footprint. Music may have developed from rhythmic sounds produced by daily chores, for example, cracking open nuts with stones. Maintaining a rhythm while working may have helped people to become more efficient at daily activities. An alternative theory originally proposed by Charles Darwin explains that music may have begun as a hominin mating strategy. Bird and other animal species produce music such as calls to attract mates. This hypothesis is generally less accepted than the previous hypothesis, but nonetheless provides a possible alternative. Upper Paleolithic (and possibly Middle Paleolithic) humans used flute-like bone pipes as musical instruments, and music may have played a large role in the religious lives of Upper Paleolithic hunter-gatherers. As with modern hunter-gatherer societies, music may have been used in ritual or to help induce trances. In particular, it appears that animal skin drums may have been used in religious events by Upper Paleolithic shamans, as shown by the remains of drum-like instruments from some Upper Paleolithic graves of shamans and the ethnographic record of contemporary hunter-gatherer shamanic and ritual practices.
==== Black People's Convention ==== In August 1971, Biko attended a conference on "The Development of the African Community" in Edendale. There, a resolution was presented calling for the formation of the Black People's Convention (BPC), a vehicle for the promotion of Black Consciousness among the wider population. Biko voted in favour of the group's creation but expressed reservations about the lack of consultation with South Africa's Coloureds or Indians. A. Mayatula became the BPC's first president; Biko did not stand for any leadership positions. The group was formally launched in July 1972 in Pietermaritzburg. By 1973, it had 41 branches and 4000 members, sharing much of its membership with SASO.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide composed of four amino acids: alanine, glutamate, aspartate, and glycine. It is written as Ala-Glu-Asp-Gly. The free peptide has a molecular weight of about 390 daltons and is normally supplied as a lyophilized powder.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
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.