If you have been reading about AEDG 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 2026-02-19. Numbers and descriptions here follow the published literature rather than marketing material.
Several names circulate for the same molecule, including epitalon, epithalone, epithalamin tetrapeptide, and the sequence code AEDG. A CAS registry number, 307297-39-8, is commonly cited for it, though catalogue entries should be checked against supplier documentation because mislabelled records occur. In its usual form the peptide carries free amino and carboxyl termini and is neither glycosylated nor lipidated. Researchers distinguish the defined tetrapeptide from epithalamin itself, a crude pineal preparation containing many peptides that is not chemically characterised.
Material supplied for laboratory use is normally a lyophilised white to off-white powder that dissolves readily in water and in isotonic saline. Lyophilised cakes are hygroscopic and should be equilibrated to room temperature before opening to limit condensation on the solid. Solutions are typically prepared at milligram-per-millilitre concentrations and divided into single-use aliquots, because repeated freeze–thaw cycles degrade short peptides. Aqueous solutions are far less stable than the dry powder, and identity is usually verified by mass spectrometry alongside purity estimation from reversed-phase high-performance liquid chromatography.
Epitalon is a synthetic linear tetrapeptide with the sequence alanine–glutamate–aspartate–glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and the calculated mass is approximately 390.35 g/mol. The compound is made by solid-phase peptide synthesis rather than extracted from tissue, although early work described it as a short fragment of a peptide fraction obtained from bovine pineal extract. In the research literature the spelling epitalon and the variant epithalone both appear, while AEDG is the standard code used in peptide nomenclature.
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.
The parent extract epithalamin was characterised as a low-molecular-weight fraction of pineal tissue rather than a single defined chemical entity. Researchers fractionated it and tested successive fragments for activity, a screening approach typical of peptide discovery work in that era. Epitalon emerged from that process as one of the shorter sequences of interest. Because the original extract was never fully resolved into individual components, claims about which constituent drives a given effect rest on inference. This distinction matters when reading older reports that attribute extract observations to the tetrapeptide itself.
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.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Linear tetrapeptide, also written AEDG |
| Molecular mass | About 390.35 g/mol | Value calculated from the sequence |
| Appearance | White to off-white powder | Lyophilised material forms a loose cake |
| Solubility | Freely soluble in water | Also dissolves in isotonic saline |
| Storage | -20 °C, desiccated | Aliquot solutions to avoid freeze–thaw cycling |
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.
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== Uses == The useful buffer range for tris (pH 7–9) coincides with the physiological pH typical of most living organisms. This, and its low cost, make tris one of the most common buffers in the biology/biochemistry laboratory. Tris is also used as a primary standard to standardize acid solutions for chemical analysis. Tris is used to increase permeability of cell membranes. It is a component of the Moderna COVID-19 vaccine and the Pfizer-BioNTech COVID-19 vaccine for use in children 5 through 11 years of age.
== Correlation == It has been found that the F number linearly correlates with the log k' value (logarithm of the retention factor) in aqueous reversed-phase liquid chromatography. This relationship can be used to understand the significance of different aspects of molecular architecture on their separation using different stationary phases. This size analysis is complementary to the length-to-breadth (L/B) ratio, which classifies molecules according to their "rodlike" or "squarelike" shape.
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Sources: en.wikipedia.org
== Selected books == J.W. Steed, D.R. Turner, K. Wallace Core Concepts in Supramolecular Chemistry and Nanochemistry (Wiley, 2007) 315p. ISBN 978-0-470-85867-7 Brechignac C., Houdy P., Lahmani M. (Eds.) Nanomaterials and Nanochemistry (Springer, 2007) 748p. ISBN 978-3-540-72993-8 H. Watarai, N. Teramae, T. Sawada Interfacial Nanochemistry: Molecular Science and Engineering at Liquid-Liquid Interfaces (Nanostructure Science and Technology) 2005. 321p. ISBN 978-0-387-27541-3 Ozin G., Arsenault A.C., Cademartiri L. Nanochemistry: A Chemical Approach to Nanomaterials 2nd Eds. (Royal Society of Chemistry, 2008) 820p. ISBN 978-1847558954 Kenneth J. Klabunde; Ryan M. Richards, eds. (2009). Nanoscale Materials in Chemistry (2nd ed.). Wiley. ISBN 978-0-470-22270-6.
=== Pharmacokinetics === The oral bioavailability of clomipramine is approximately 50%. Peak plasma concentrations occur around 2–6 hours (with an average of 4.7 hours) after taking clomipramine orally and are in the range of 56–154 ng/mL (178–489 nmol/L). Steady-state concentrations of clomipramine are around 134–532 ng/mL (426–1,690 nmol/L), with an average of 218 ng/mL (692 nmol/L), and are reached after 7 to 14 days of repeated dosing. Steady-state concentrations of the active metabolite, desmethylclomipramine, are around 230–550 ng/mL (730–1,750 nmol/L). The volume of distribution (Vd) of clomipramine is approximately 17 L/kg. It binds approximately 97–98% to plasma proteins, primarily to albumin. Clomipramine is metabolized in the liver mainly by CYP2D6. It has a terminal half-life of 32 hours, and its N-desmethyl metabolite, desmethylclomipramine, has a terminal half-life of approximately 69 hours. Clomipramine is mostly excreted in urine (60%) and feces (32%). Although the normal maximum-recommended total daily dosage of clomipramine is 250 milligrams, treatment-resistant cases of depression and obsessive-compulsive disorder may require corresponding doses within the range of 255 to 300 milligrams. Indeed, doses of 375 milligrams per day, sometimes in combination with venlafaxine or aripiprazole, have not only been necessary but, remarkably, relatively well-tolerated.
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=== Excretion === In humans, the major route of excretion of most arsenic compounds is via the urine. The biological half-life of inorganic arsenic is about 4 days, but is slightly shorter following exposure to arsenate than to arsenite. The main metabolites excreted in the urine of humans exposed to inorganic arsenic are mono- and dimethylated arsenic acids, together with some unmetabolized inorganic arsenic. The biotransformation of arsenic for excretion is primarily done through the nuclear factor erythroid 2 related factor 2 (Nrf2) pathway. Under normal conditions the Nrf2 is bound to Kelch-like ECH associated protein 1 (Keap1) in its inactive form. With the uptake of arsenic within cells and the subsequent reactions that result in the production of reactive oxygen species (ROS), the Nrf2 unbinds and becomes active. Keap1 has reactive thiol moieties that bind ROS or electrophilic arsenic species such as monomethylted arsenic (III) and induces the release of Nrf2 which then travels through the cytoplasm to the nucleus. The Nrf2 then activates antioxidant responsive element (ARE) as well as electrophilic responsive element (EpRE) both of which contribute in the increase of antioxidant proteins. Of particular note in these antioxidant proteins is heme oxygenase 1 (HO-1), NAD(P)H-quinone oxidoreductase 1 (NQO1), and γ-glutamylcysteine synthase (γGCS) which work in conjunction to reduce the oxidative species such as hydrogen peroxide to decrease the oxidative stress upon the cell.
Sources: en.wikipedia.org
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Allan Maxam and Walter Gilbert published a DNA sequencing method in 1977 based on chemical modification of DNA and subsequent cleavage at specific bases. Also known as chemical sequencing, this method allowed purified samples of double-stranded DNA to be used without further cloning. This method's use of radioactive labeling and its technical complexity discouraged extensive use after refinements in the Sanger methods had been made. Maxam-Gilbert sequencing requires radioactive labeling at one 5' end of the DNA and purification of the DNA fragment to be sequenced. Chemical treatment then generates breaks at a small proportion of one or two of the four nucleotide bases in each of four reactions (G, A+G, C, C+T). The concentration of the modifying chemicals is controlled to introduce on average one modification per DNA molecule. Thus a series of labeled fragments is generated, from the radiolabeled end to the first "cut" site in each molecule. The fragments in the four reactions are electrophoresed side by side in denaturing acrylamide gels for size separation. To visualize the fragments, the gel is exposed to X-ray film for autoradiography, yielding a series of dark bands each corresponding to a radiolabeled DNA fragment, from which the sequence may be inferred. This method is mostly obsolete as of 2023.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide. Its sequence was derived from research on peptide fractions of bovine pineal extract, and the intact AEDG sequence has not been demonstrated as an abundant free peptide in human tissue.
AEDG is the one-letter code for the four amino acids alanine, glutamate, aspartate and glycine in that order. The same molecule is written in three-letter form as Ala-Glu-Asp-Gly.
Identity is normally confirmed by mass spectrometry against the calculated mass of roughly 390.35 g/mol. Purity is then estimated by reversed-phase high-performance liquid chromatography with ultraviolet detection.
It is based on epithalamin, a peptide-rich preparation obtained from pineal gland tissue and studied in the former Soviet Union. Researchers later identified the tetrapeptide AEDG as a constituent fragment of that material. Modern supplies are produced by chemical synthesis rather than tissue extraction.