If you have been reading about Deamidation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-01-08. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography with ultraviolet detection, frequently near 214 nanometers where the peptide bond absorbs. Mass spectrometry, most often with electrospray ionization, confirms the observed molecular mass and helps separate the intact peptide from truncated or modified forms. Amino acid analysis or tandem mass spectrometry can establish residue order. Purity is commonly quoted as an area percentage, yet such values are method-dependent, and comparisons between laboratories require matching column, gradient and detection wavelength.
| 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 |
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
The compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
Verification of research-grade material involves comparing a supplier chromatogram against an in-house reference, checking the observed mass against the calculated value, and where possible confirming residue order by tandem mass spectrometry or enzymatic peptide mapping. Purity claims should be read alongside the method used to obtain them, because detection wavelength and integration settings alter the result. Batch-specific data, rather than a generic grade statement, is the informative part of a certificate.
Identity and purity of epitalon samples are normally established by reversed-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres, combined with mass spectrometry. The mass spectrum confirms the expected molecular ion and can reveal truncated or oxidised by-products. Amino acid analysis after acid hydrolysis verifies that the four residues are present in the expected ratio. Certificates typically report a purity figure taken from chromatographic peak area, expressed as a percentage of total integrated signal.
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.
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.
==== Major depressive disorder ==== Modafinil has been studied as an adjunctive treatment for major depressive disorder. While some individual trials have reported benefits, systematic reviews and meta-analyses have found the evidence limited, the quality of evidence low, and the results inconclusive; modafinil did not significantly improve depression in network meta-analysis, though there was some evidence for reduced fatigue and sleepiness.
== Clinical significance == Mutations in the 38 human genes for the cytoplasmic and mitochondrial enzymes have been associated with a wide range of illnesses, with 56+ different diseases given OMIM codes. The majority of reported diseases (46/56) were autosomal recessive. Nearly every reported aminoacyl-tRNA synthetase gene has been associated with at least one disease caused by mutations (with the notable exception of TARS3). Mutations in the mitochondrial enzyme have been associated with a number of genetic disorders including Leigh syndrome, West syndrome and CAGSSS (cataracts, growth hormone deficiency, sensory neuropathy, sensorineural hearing loss and skeletal dysplasia syndrome).
=== Literature === The Bowery is the setting for Stephen Crane's first novel, Maggie: A Girl of the Streets (published in 1893), about a poor family living in the neighborhood. New York School poet Ted Berrigan mentions the Bowery several times in his seminal work "The Sonnets." Jack Kirby and Stan Lee's Fantastic Four #4 (1962), the Human Torch flees to the Bowery to lose himself "among all the other human derelicts..." In one of the Bowery's flophouses, he discovers the amnesiac 1940s-era character Namor the Sub-Mariner. The Wild Cards series of books sets the Bowery as Jokertown, the place where the malformed go to live after the Wild Card Virus is released over New York. Brenda Coultas' 2003 book of poetry, A Handmade Museum, contains a section called "the Bowery Project" which documents the pre-gentrification process.
Compared with non-parents, parents with children have lower levels of well-being and life satisfaction until children move out of the household, at which point parents have higher well-being and satisfaction. In addition, parents report more feelings of depression and anxiety than non-parents. However, when adults without children are compared to empty nest parents, parenthood is positively associated with emotional well-being. People found parenthood to be more stressful in the 1970s than they did in the 1950s. This is thought to be because of social changes in regards to employment and marital status. Males apparently become less happy after the birth of a child due to added economic pressure and taking on the role of being a parent. A conflict between partners can arise when the couple does not desire traditional roles, or has an increasing number of roles. Unequal responsibilities of child-rearing between men and women account for this difference in satisfaction. Fathers who worked and shared an equal part in child-raising responsibilities were found to be the least satisfied. Research shows that single parents have higher levels of distress and report more mental health problems than married persons. Researchers implemented the Huta & Ryan Scale: Four Eudaimonic Measurement Questionnaire to analyze the participants eudaimonic motives, through motivation towards activities. The investigation was conducted on Canadian university undergraduates. The four eudaimonic pursuits as described by Huta & Ryan are:
Sources: en.wikipedia.org
Meanwhile, sequencing of human cDNA sequences called expressed sequence tags began in Craig Venter's lab, an attempt to capture the coding fraction of the human genome. In 1995, Venter, Hamilton Smith, and colleagues at The Institute for Genomic Research (TIGR) published the first complete genome of a free-living organism, the bacterium Haemophilus influenzae. The circular chromosome contains 1,830,137 bases and its publication in the journal Science marked the first published use of whole-genome shotgun sequencing, eliminating the need for initial mapping efforts. By 2003, the Human Genome Project's shotgun sequencing methods had been used to produce a draft sequence of the human genome; it had a 92% accuracy. In 2022, scientists successfully sequenced the last 8% of the human genome. The fully sequenced standard reference gene is called GRCh38.p14, and it contains 3.1 billion base pairs.
=== Alkylation, acylation, and sulfonation, etc. === Aside from their basicity, the dominant reactivity of amines is their nucleophilicity. Most primary amines are good ligands for metal ions to give coordination complexes. Amines are alkylated by alkyl halides. Acyl chlorides and acid anhydrides react with primary and secondary amines to form amides (the "Schotten–Baumann reaction").
== French domestic situation == The 1946 Constitution creating the Fourth Republic (1946–1958) made France a parliamentary republic. Because of the political context, it could find stability only by an alliance between the three dominant parties: the Christian Democratic Popular Republican Movement (MRP), the French Communist Party (PCF) and the socialist French Section of the Workers' International (SFIO). Known as tripartisme, this alliance briefly lasted until the May 1947 crisis, with the expulsion from Paul Ramadier's SFIO government of the PCF ministers, marking the official start of the Cold War in France. This had the effect of weakening the regime, with the two most significant movements of this period, Communism and Gaullism, in opposition. A strong anti-war movement came into existence in France driven mostly by the powerful French Communist Party (outpowering the socialists) and its young militant associations, major trade unions such as the General Confederation of Labour, and notable leftist intellectuals. The first occurrence was probably at the National Assembly on March 21, 1947, when the communist deputies refused to back the military credits for Indochina. The following year a pacifist event was organized, the "1st Worldwide Congress of Peace Partisans" (1er Congrès Mondial des Partisans de la Paix, the World Peace Council's predecessor), which took place March 25–28, 1948, in Paris, with the French communist Nobel laureate atomic physicist Frédéric Joliot-Curie as president.
However, p21 can also be induced independently of p53 during processes such as differentiation, development, and in response to serum stimulation. p21 (WAF1) binds to cyclin-CDK complexes (notably CDK2, CDK1, CDK4, and CDK6), inhibiting their activity and blocking the G1/S transition. This inhibition enforces a cell cycle pause that allows DNA repair to occur. In cells with functional p53, p21 is upregulated in response to DNA damage, ensuring this checkpoint control. In contrast, p53 mutations impair p21 induction and compromise this control. In human embryonic stem cells (hESCs), although p21 mRNA is upregulated following DNA damage, the protein is not detectable. This reflects a nonfunctional p53-p21 axis at the G1/S checkpoint. This discrepancy is largely due to post-transcriptional repression, particularly by the miR-302 family of microRNAs, which inhibit p21 translation. Although p53 binds the CDKN1A promoter in hESCs, it does not regulate miR-302, which is constitutively expressed and suppresses p21 expression. The p53 pathway is interconnected with the RB1 pathway via p14^ARF, which links the regulation of these key tumor suppressors. p53 expression can be induced by UV radiation, which also causes DNA damage. In this context, p53 activation can initiate processes that lead to melanin production and tanning.
=== Disability and death === Due to distance, Hodgkin decided not to attend the 1987 Congress of the International Union of Crystallography in Australia. However, despite increasing frailty, she astounded close friends and family by going to Beijing for the 1993 Congress, where she was welcomed by all. She died in July 1994 after a stroke, at her husband's home in the village of Ilmington, near Shipston-on-Stour, Warwickshire.
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.
The dry powder is typically held at -20 degrees Celsius or lower, protected from light and moisture. Allowing a sealed vial to reach room temperature before opening reduces condensation on its contents. Conditions stated on a supplier certificate of analysis take precedence over general guidance.