Deamidation comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2025-07-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
== Presentation of native intact antigens to B cells == B-cell receptors on the surface of B cells bind to intact native and undigested antigens of a structural nature, rather than to a linear sequence of a peptide which has been digested into small fragments and presented by MHC molecules. Large complexes of intact antigen are presented in lymph nodes to B cells by follicular dendritic cells in the form of immune complexes. Some APCs expressing comparatively lower levels of lysosomal enzymes are thus less likely to digest the antigen they have captured before presenting it to B cells.
Clinical trials of isotretinoin, etidronate with oral corticosteroids, and perhexiline maleate have failed to demonstrate effectiveness, though the variable course of the disease and small prevalence induces uncertainty. A handful of pharmaceutical companies focused on rare diseases are currently in varying stages of investigation into different therapeutic approaches for FOP. In August 2015, the U.S. Food and Drug Administration (FDA) Office of Orphan Products Development granted La Jolla Pharmaceuticals orphan drug designation for two novel compounds for FOP. The compounds are small-molecule protein kinase inhibitors designed to selectively block ACVR1 (ALK2). In August 2015, Clementia Pharmaceuticals began the enrollment of children (ages 6 and above) into its Phase II clinical trial investigating palovarotene for the treatment of FOP. Preclinical studies demonstrated that palovarotene, a retinoic acid receptor gamma agonist, blocked abnormal bone formation in animal models by inhibition of secondary messenger systems in the BMP pathway. Clementia licensed palovarotene from Roche Pharmaceuticals, which previously evaluated the compound in more than 800 individuals including healthy volunteers and patients with chronic obstructive pulmonary disease. Palovarotene received Fast Track designation from the FDA and orphan designations for the treatment of FOP from both the FDA and the European Medicines Agency (EMA). In the pivotal phase 3 MOVE trial published in 2023, Sohonos was shown to reduce new heterotropic ossification by 54-60%.
=== Applications in pharmaceutical industry === A typical use of ultrapure water in pharmaceutical and biotechnology industries is summarized in the table below: Uses of ultrapure water in the pharmaceutical and biotechnology industries
== Molecules == The following tables list molecules that have been detected in the interstellar medium or circumstellar matter, grouped by the number of component atoms. Neutral molecules and their molecular ions are listed in separate columns; if there is no entry in the molecule column, only the ionized form has been detected. Designations (names of molecules) are those used in the scientific literature describing the detection; if none was given that field is left empty. Mass is listed in daltons. Deuterated molecules, which contain at least one deuterium (2H) atom, have slightly different masses and are listed in a separate table. The total number of unique species, including distinct ionization states, is indicated in each section header. Most of the molecules detected so far are organic. The only detected inorganic molecule with five or more atoms is SiH4. Molecules larger than that all have at least one carbon atom, with no N−N or O−O bonds.
Sources: en.wikipedia.org
This is governed by the signal recognition particle—a protein that binds to the ribosome and directs it to the endoplasmic reticulum when it finds a signal peptide on the growing (nascent) amino acid chain.
In biology the term 'condensation' is used much more broadly and can also refer to liquid–liquid phase separation to form colloidal emulsions or liquid crystals within cells, and liquid–solid phase separation to form gels, sols, or suspensions within cells as well as liquid-to-solid phase transitions such as DNA condensation during prophase of the cell cycle or protein condensation of crystallins in cataracts. With this in mind, the term 'biomolecular condensates' was deliberately introduced to reflect this breadth (see below). Since biomolecular condensation generally involves oligomeric or polymeric interactions between an indefinite number of components, it is generally considered distinct from formation of smaller stoichiometric protein complexes with defined numbers of subunits, such as viral capsids or the proteasome – although both are examples of spontaneous molecular self-assembly or self-organisation. Mechanistically, it appears that the conformational landscape (in particular, whether it is enriched in extended disordered states) and multivalent interactions between intrinsically disordered proteins (including cross-beta polymerisation), and/or protein domains that induce head-to-tail oligomeric or polymeric clustering, might play a role in phase separation of proteins.
=== 1989 === 9 July Moving Pictures, with Sir Jonathan Miller, the documentary explains how the brain sees images, with relation to television; Gotthold Ephraim Lessing and his work Laocoön; animator Sergio Simonetti; the National Science and Media Museum in Bradford; the Asteroid theme of Pearl & Dean; cognitive scientist Jerome Lettvin; John Grover and the 1989 film Licence to Kill; with the documentary editor Simon Rose. Produced by Patrick Uden, directed by Michael Proudfoot, made by Uden Associates 23 July The Bicycle: The Green Machine, Columbus of Italy that made cycle steel tubing from 130 kg steel billets; Cinelli of Milan; sports scientist Adrienne Hardman of Loughborough University; cycle chains were mostly made in Japan; 2m would be sold in UK - 700k by Raleigh. Narrated by the Radio 4 newsreader John Hedges, produced by Jeremy Llewellyn-Jones, made by Chrysalis Television 30 July Earth Calling Basingstoke, about Guy Hurst, who collates sightings for The Astronomer (BAA); Dave Graham from Brompton-on-Swale; John Wall, known for his Crayford focuser; the documentary was filmed around April 1989, and the astronomers in County Durham saw the effects of the March 1989 geomagnetic storm.
In another study with escitalopram citalopram, metabolomic analysis of plasma from patients with MDD revealed that variations in glycine metabolism were negatively associated with patient outcome upon treatment with selective serotonin reuptake inhibitors (SSRIs), an important drug class involved in the treatment of this disease.
The dynamics of an epidemic, for example, the flu, are often much faster than the dynamics of birth and death, therefore, birth and death are often omitted in simple compartmental models. The SIR system without so-called vital dynamics (birth and death, sometimes called demography) described above can be expressed by the following system of ordinary differential equations:
Sources: en.wikipedia.org
== Further reading == Kleerebezem M, Boekhorst J, van Kranenburg R, et al. (February 2003). "Complete genome sequence of Lactobacillus plantarum WCFS1". Proceedings of the National Academy of Sciences of the United States of America. 100 (4): 1990–1995. Bibcode:2003PNAS..100.1990K. doi:10.1073/pnas.0337704100. JSTOR 3138472. PMC 149946. PMID 12566566.
4 11H + 2 e− → 42He + 2 e+ + 2 e− + 2 νe + 3 γ + 24.7 MeV → 42He + 2 νe + 7 γ + 26.7 MeV The positrons will almost instantly annihilate with electrons, releasing energy in the form of gamma rays. The neutrinos escape from the star carrying away some energy. One nucleus goes on to become carbon, nitrogen, and oxygen isotopes through a number of transformations in a repeating cycle.
Hood's research group corrected the neurological defect in mice (the shiverer defect) by transferring a normal MBP gene into the fertilized egg of the shiverer mouse. These discoveries led to extensive studies of MBP and its biology.
=== Occurrence in bacteria === Hydrogen cyanide is produced by various soil bacteria, including cyanobacteria and representatives of the genera Aeromonas, Bacillus, and Pseudomonas. Biosynthesis proceeds from glycine. A group of alkanenitriles was isolated from Pseudomonas veronii: dodecannitrile, tridecannitrile, tetradecanenitrile, pentadecannitrile, and hexadecannitrile, as well as compounds of similar chain length containing a double bond. From Micromonospora echinospora, structurally related compounds were also isolated, differing by a terminal methyl branch, a double bond, or both. A cyanohydrin containing a phosphonic acid moiety is known from Streptomyces regensis. The aetokthonotoxin from the cyanobacteria Aetokthonos hydrillicola is a brominated indole derivative bearing a nitrile group. It is a potent neurotoxin that frequently causes mortality in bald eagles that ingest it.
Integrated treatment can improve accessibility, service individualization, engagement in treatment, treatment compliance, mental health symptoms, and overall outcomes. The Substance Abuse and Mental Health Services Administration in the United States describes integrated treatment as being in the best interests or clients, programs, funders, and systems. Green suggested that treatment should be integrated, and a collaborative process between the treatment team and the patient. Furthermore, recovery should to be viewed as a marathon rather than a sprint, and methods and outcome goals should be explicit. Comprehensive integrated programs commonly combine pharmacotherapy with psychosocial interventions, continuous and coordinated assessment, and long-term relapse-prevention support, with the intensity of services matched to a client's stage of readiness for change. A 2019 Cochrane meta-analysis that included 41 randomized controlled trials found no high-quality evidence in support of any one psycho-social intervention over standard care for outcomes such as remaining in treatment, reduction in substance use and/or improvement in global functioning and mental status.
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.