This is a working overview of epithalamin, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-06. Anything still debated is marked as such rather than presented as settled.
（TG:@pojiaai）Epitalon is a synthetic linear tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. It emerged from work on epithalamin, a peptide fraction prepared from bovine pineal tissue, and was designed as a short, chemically defined analogue of that extract. Early publications came mainly from Russian laboratories studying pineal peptides and aging-related endpoints. The compound appears in the literature under several spellings, including epithalon and epithalone, which complicates systematic searching. Its small size makes solid-phase assembly and routine analytical characterization straightforward.
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.
Epitalon is a synthetic tetrapeptide with the amino acid sequence alanine-glutamate-aspartate-glycine, abbreviated Ala-Glu-Asp-Gly or AEDG. It was developed by the Russian researcher Vladimir Khavinson and colleagues during work on peptide bioregulators derived from the pineal gland. The compound is short enough to be produced by standard solid-phase peptide synthesis and is typically handled as a lyophilized white powder. Its small size distinguishes it from larger pineal peptides such as epithalamin, a complex extract from which the tetrapeptide was conceptually derived.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Linear tetrapeptide | Four residues joined by three peptide bonds |
| Sequence | Ala-Glu-Asp-Gly | Commonly abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free acid form |
| Monoisotopic mass | Approximately 390 Da | Matches values reported from mass spectrometry |
| Net charge near neutral pH | Negative | Contributed by glutamate and aspartate side chains |
The flexible finger bones of bats have a flattened cross-section and become less mineralised towards the tips. The elongation of bat digits, a key feature required for wing development, is due to the upregulation of bone morphogenetic proteins (BMPs). During embryonic development, the gene controlling BMP signalling, BMP-2, is subjected to increased expression in bat forelimbs – resulting in the extension of the manual digits. This crucial genetic alteration helps create the specialised limbs required for powered flight. The relative proportion of extant bat forelimb digits compared with those of Eocene fossil bats have no significant differences, suggesting that bat wing morphology has been conserved for over fifty million years. During flight, the bones undergo bending and shearing stress; the former being less than in terrestrial mammals, and the latter being greater. The wing bones of bats are less resistant to breaking than those of birds. As in other mammals, and unlike in birds, the radius is the main component of the forearm. Bats have five elongated digits, which all radiate around the wrist. The thumb points forward and supports the leading edge of the wing, and the other digits support the tension held in the wing membrane. The second and third digits go along the wingtip, allowing the wing to be pulled forward against aerodynamic drag without having to be thick, as in pterosaur wings. The fourth and fifth digits go from the wrist to the trailing edge and repel the bending force caused by air pushing up against the stiff membrane.
== Chemistry == Mirtazapine is a tetracyclic piperazinoazepine; mianserin was developed by the same team of organic chemists and mirtazapine differs from it via the addition of a nitrogen atom in one of the rings. It is a racemic mixture of enantiomers. The (S)-(+)-enantiomer is known as esmirtazapine. Analogues of mirtazapine include mianserin, setiptiline, and aptazapine.
=== Gross composition === Published data on donkey milk's gross composition confirm the close resemblance to breast milk for lactose, protein, and ash levels when compared with cow, sheep and goat milk. Despite the high lactose content of donkey milk, the average fat content is lower. When used in infant nutrition, donkey milk is usually supplemented with vegetable oil (4 mL per 100 mL of milk) to conform to human milk energy.
Sources: en.wikipedia.org
== Structure == The gene coding for DPEP1 is 6 kb long and consists of ten exons and nine introns. The protein itself is made of 411 amino acid residues and is only transcribed in kidney cells. Although disulfide linkages in DPEP1 do not contribute to the enzyme’s activity, they are essential for the enzyme’s proper function because they keep the enzyme’s subunits together and attached to the renal brush border. Cysteine 261 is involved in disulfide linkage between the enzyme’s subunits, and is also located very close to both the site of the GPI-anchor and the membrane, suggesting that it is also involved in the enzyme’s linkage to the membrane. DPEP1 is also a metalloenzyme that specifically uses zinc as its cofactor. The enzyme’s typical zinc content is 1.42 ug/mg. The addition of cobalt or manganese ions cause the enzyme to take on different conformations, which suggests that the enzyme may be able to hydrolyze different dipeptides depending on which metal ions are present—aka the metal-content of one’s micronutrient intake could affect their renal dipeptidase’s ability to metabolize various dipeptides.
== Ionization mechanisms == The photoionization mechanism is simplified under vacuum conditions: photon absorption by the analyte molecule, leading to electron ejection, forming a molecular radical cation, M•+. This process is similar to electron ionization common to GC/MS, except that the ionization process is soft, i.e., less fragmentation. In the atmospheric region of an LC/MS system, the ionization mechanism becomes more complex. The unpredictable fate of ions is generally detrimental to LC/MS analysis, but like most processes, once they are better understood, these properties can be exploited to enhance performance. For example, the role of dopant in APPI, first developed and patented for the atmospheric ion source of ion mobility spectrometry (IMS), was adapted to APPI for LC/MS. The basic APPI mechanisms can be summarized by the following scheme: Direct positive ion APPI
It was nominated for numerous awards and won "Best VR/AR" at the 2020 Game Awards. Valve acknowledged that the audience for VR games was limited, and Gabe Newell, Valve's president, described Alyx as a long-term investment into new technologies. As of 2024, it had sold more than two million copies. In 2026, Valve ported Alyx to its standalone Steam Frame headset.
Sources: en.wikipedia.org
It is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, often abbreviated AEDG. The molecule is linear and contains no modified residues, so it is fully described by its sequence.
The compound came out of work on epithalamin, a peptide preparation derived from pineal tissue, conducted largely in Russian laboratories. Later studies in other countries examined it mainly in cell cultures and animal models.
The tetrapeptide sequence is a synthetic construct rather than a described circulating peptide. It was derived by analogy to peptide fractions obtained from tissue extracts, not isolated from blood or tissue as such.
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.