tetrapeptide 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 2026-06-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
（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.
| Property | Value | Notes |
|---|---|---|
| Amino acid sequence | Ala-Glu-Asp-Gly | Tetrapeptide, often abbreviated AEDG |
| Molecular formula | C14H22N4O9 | Free peptide, unmodified termini |
| Molecular weight | ~390.35 Da | Calculated for the free acid form |
| Appearance | White to off-white powder | Typical lyophilized product form |
| Solubility class | Freely soluble in water | Two acidic residues dominate ionic character |
==== MeSH E05.601.495 – immunoassay ==== MeSH E05.601.495.320 – immunoblotting MeSH E05.601.495.320.200 – blotting, western MeSH E05.601.495.350 – immunoenzyme techniques MeSH E05.601.495.350.170 – enzyme-linked immunosorbent assay MeSH E05.601.495.350.180 – enzyme multiplied immunoassay technique MeSH E05.601.495.380 – immunosorbent techniques MeSH E05.601.495.380.360 – enzyme-linked immunosorbent assay MeSH E05.601.495.380.810 – radioallergosorbent test MeSH E05.601.495.380.825 – radioimmunoprecipitation assay MeSH E05.601.495.380.830 – radioimmunosorbent test MeSH E05.601.495.639 – radioimmunoassay MeSH E05.601.495.639.405 – immunoradiometric assay MeSH E05.601.495.639.810 – radioallergosorbent test MeSH E05.601.495.639.825 – radioimmunoprecipitation assay MeSH E05.601.495.639.830 – radioimmunosorbent test
==== Interactions with other nephrotoxins ==== Another area of controversy and uncertainty is whether and to what extent vancomycin increases the toxicity of other nephrotoxins. Clinical studies have yielded various results, but animal models indicate that the nephrotoxic effect probably increases when vancomycin is added to nephrotoxins such as aminoglycosides. A dose- or serum level-effect relationship has not been established.
== Comparison to SSRIs == As SNRIs were developed more recently than SSRIs, there are relatively few of them. However, the SNRIs are among the most widely used antidepressants today. In 2009, Cymbalta and Effexor were the 11th- and 12th-most-prescribed branded drugs in the United States, respectively. This translates to the 2nd- and 3rd-most-common antidepressants, behind Lexapro (escitalopram), an SSRI. In some studies, SNRIs demonstrated slightly higher antidepressant efficacy than the SSRIs (response rates 63.6% versus 59.3%). However, in one study escitalopram had a superior efficacy profile to venlafaxine. SSRIs do not significantly increase norepinephrine, which is where SNRIs may be used for a greater variety of conditions involving norepinephrine, such as chronic pain disorders. Some additional side effects noted with SNRIs can include increased heart rate and blood pressure. Overall, most patients are able to tolerate both similarly, and their choice depends more on their symptoms, medical history, and previous response to antidepressants.
Sources: en.wikipedia.org
== Principle == Modified Russell–Movat staining highlights numerous tissue components in histological slides. It is obtained by a mix of five stains: alcian blue, Verhoeff hematoxylin and crocein scarlet combined with acidic fuchsine and saffron. At pH 2.5, alcian blue is fixed by electrostatic binding with the acidic mucopolysaccharides. The Verhoeff hematoxylin has a high affinity for nuclei and elastin fibers, negatively charged. The combination of crocein scarlet with acidic fuchsine stains acidophilic tissue components in red. Then, collagen and reticulin fibers are unstained by a reaction with phosphotungstic acid and stained in yellow by saffron.
==== Entrapment of catalytically active noble metal nanoparticles ==== The entrapment of catalytically active noble metals can be accomplished by grafting on functional groups to the unsaturated metal site on MOFs. Ethylenediamine (ED) has been shown to be grafted on the Cr metal sites and can be further modified to encapsulate noble metals such as Pd. The entrapped Pd has similar catalytic activity as Pd/C in the Heck reaction. Ruthenium nanoparticles have catalytic activity in a number of reactions when entrapped in the MOF-5 framework. This Ru-encapsulated MOF catalyzes oxidation of benzyl alcohol to benzaldehyde, although degradation of the MOF occurs. The same catalyst was used in the hydrogenation of benzene to cyclohexane. In another example, Pd nanoparticles embedded within defective HKUST-1 framework enable the generation of tunable Lewis basic sites. Therefore, this multifunctional Pd/MOF composite is able to perform stepwise benzyl alcohol oxidation and Knoevenagel condensation.
=== Colon Treaty of Peace and Friendship === On August 26, 1876, the Grand Lodge of Colon in Santiago de Cuba declared itself entirely independent as a sovereign Masonic Body with its own full and unlimited powers over its own subordinate lodges. Under their auspices, the Grand Lodge of Colon possessed 36 lodges and 8,000 members. On November 24, 1876, the Grand Lodge of Colon and the Supreme Council of Colon signed the Tratado de Paz y Amistad (English: Treaty of Peace and Friendship). This treaty was based in the agreements of the Lausanne Congress. It degraded the superior prestige of the higher degrees, eliminated authoritarian positions at the Supreme Council, ejected the Spanish aristocracy from holding undue power, and erased the mystical positions. The Supreme Council of Colon recognized the Grand Lodge of Colon as "regular and correct," and also recognized their authority over the three degrees of the Blue Lodge. The Grand Lodge recognized the Supreme Council as the authority over the 4th to 33rd degrees.
Sources: en.wikipedia.org
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.
No. Epitalon is chemically synthesized, not extracted. It was designed as a short synthetic fragment conceptually related to larger pineal peptides studied in the same research tradition, particularly the extract known as epithalamin. The two are distinct materials with different compositions.
The term bioregulator is used in this research tradition for short peptides proposed to influence gene expression or cell function. Epitalon is grouped with other synthetic short peptides under this label. The term reflects a proposed mechanism rather than an established drug classification.
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.