This is a working overview of tetrapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-07-24. 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.
| 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 |
To emphasise that there was now only one Indian Army, and that all units were to be trained and deployed without regard for their regional origins, the regiments were renumbered into single sequences of cavalry, artillery, infantry of the line, and Gurkha Rifles. Regimental designations were altered to remove all references to the former Presidency Armies. Where appropriate subsidiary titles recalling other identifying details were adopted. Thus the 2nd Bengal Lancers became the 2nd Lancers (Gardner's Horse). The new order began with the Bengal regiments, followed by the Punjab Frontier Force, then the regiments of Madras, the Hyderabad Contingent, and Bombay. Wherever possible a significant digit was retained in the new number. Thus the 1st Sikh Infantry became the 51st Sikhs, the 1st Madras Pioneers became the 61st Pioneers, and the 1st Bombay Grenadiers became the 101st Grenadiers. The Gurkha Regiments had developed into their own Line of rifle regiments since 1861. They were five of these until they were joined by the former 42nd, 43rd, & 44th Gurkha Regiments of the Bengal Army, who became the 6th, 7th, & 8th Gurkha Rifles. The numbers 42, 43, & 44 were allocated respectively to the Deoli and Erinpura Irregular Forces and the Mhairwara Battalion from Rajputana.
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===== Cocaine-induced midline destructive lesions ===== Cocaine-induced midline destructive lesions (CIMDL) is the progressive destruction of nasal architecture with the erosion of the palate, nasal conchae, and ethmoid sinuses associated with prolonged insufflation, colloquially 'snorting', of cocaine. Chronic intranasal usage can degrade the cartilage separating the nostrils (the septum nasi), leading eventually to its complete disappearance.
Sources: en.wikipedia.org
=== Difference and complementarity with two-photon fluorescence (2PEF) === Two-photons fluorescence (2PEF) is a very different process from SHG: it involves excitation of electrons to higher energy levels, and subsequent de-excitation by photon emission (unlike SHG, although it is also a 2-photon process). Thus, 2PEF is a non coherent process, spatially (emitted isotropically) and temporally (broad, sample-dependent spectrum). It is also not specific to certain structure, unlike SHG. It can therefore be coupled to SHG in multiphoton imaging to reveal some molecules that do produce autofluorescence, like elastin in tissues (while SHG reveals collagen or myosin for instance).
The majority of the company's employees are based in Europe, with the majority of these at manufacturing and research and development facilities in Jilemnice and Slavkov in the Czech Republic. The company's largest manufacturing site by volume is also the newest, in Nantong, China, other manufacturing and technical plants are located in Jilemnice, Czech republic, Sandy Run, South Carolina in the United States and Bathurst, New South Wales in Australia.
An addition to the Special Metallurgical building weapon component production facility was completed at the end of 1964 for 238Pu heat source fuel fabrication. A temporary fuel production facility was also installed in the Research Building in 1969 for Transit fuel fabrication. With completion of the weapons component project, the Special Metallurgical Building, nicknamed "Snake Mountain" because of the difficulties encountered in handling large quantities of 238Pu, ceased operations on June 30, 1968, with 238Pu operations taken over by the new Plutonium Processing Building, especially designed and constructed for handling large quantities of 238Pu. Plutonium-238 is given the highest relative hazard number (152) of all 256 radionuclides evaluated by Karl Z. Morgan et al. in 1963.
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.