A practical reference on Epitalon: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-29 and is reviewed periodically as new material appears.
Epitalon is a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, abbreviated AEDG. Its molecular formula is C14H22N4O9 and its calculated monoisotopic mass is approximately 390.35 daltons. The compound does not occur naturally as a free peptide; it is produced by solid-phase peptide synthesis. Because it contains two acidic residues and no basic residues, the neutral form carries a net negative charge at physiological pH. This charge profile influences how the peptide behaves in solution and during chromatographic analysis.
Laboratory-grade epitalon is typically supplied as a lyophilized powder. Purity is commonly assessed with reverse-phase high-performance liquid chromatography, often paired with mass spectrometry to confirm molecular identity. Amino acid analysis and peptide mapping can provide additional confirmation of sequence. Certificates of analysis for research materials frequently report purity above 95 percent, although the methods behind such figures vary between suppliers. The absence of a pharmacopeial monograph means that no single standardized assay defines the compound, so reported results depend on the analytical protocol chosen.
Storage practice centres on limiting moisture, oxygen, and repeated temperature cycling. Freeze-dried powder is generally held desiccated at minus twenty degrees Celsius or colder and protected from light. Reconstituted solutions are markedly less stable, and the aspartate-glycine junction is prone to succinimide formation at neutral to mildly alkaline pH. Portioning material into single-use aliquots reduces degradation compared with repeated freeze-thaw cycles. Stability data specific to this tetrapeptide remain scarce, so most handling guidance is extrapolated from general peptide chemistry rather than measured directly.
Documentation accompanying research peptides usually includes a certificate of analysis listing the batch number, purity figure, and test methods applied. Buyers comparing suppliers should check whether the reported purity refers to chromatographic area or to a mass-balance calculation, because the two are not equivalent. Counter-ion content, residual solvents, and water content are sometimes omitted from such certificates even though they affect the actual peptide mass present. Independent verification through a second laboratory is the most direct way to confirm that a supplied material matches its label.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C14H22N4O9 | Free acid form of the tetrapeptide |
| Molecular mass | About 390.35 Da | Calculated monoisotopic value |
| Appearance | White to off-white powder | Typical lyophilized presentation |
| Solubility | Soluble in water | Also dissolves in buffered saline |
| Storage temperature | Minus 20 degrees Celsius | Dry, dark conditions; avoid repeated thawing |
Epitalon is the common name for a synthetic tetrapeptide with the sequence alanine-glutamate-aspartate-glycine, usually abbreviated AEDG. All four residues are proteinogenic amino acids, and the free peptide has a calculated mass near 390 grams per mole. Because the chain is short and carries no modifications, it is assembled readily by solid-phase synthesis and is distributed mainly as a freeze-dried solid for laboratory work. Catalogue listings use the spellings epitalon, epithalone, and simply AEDG, and the three refer to the same sequence.
The compound is generally presented as a synthetic fragment of epithalamin, a pineal gland extract investigated in the former Soviet Union from the 1970s onward. Vladimir Khavinson and colleagues in Saint Petersburg developed short peptides modelled on such extracts, and epitalon became the most widely cited of those sequences. Most primary reports appeared in Russian-language journals or in proceedings with limited international circulation. Independent replication in laboratories outside that network remains sparse, and much repeated secondary material traces back to a small number of originating groups.
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.
=== Amino acid synthesis === Six essential amino acids and three nonessential are synthesized from oxaloacetate and pyruvate. Aspartate and alanine are formed from oxaloacetate and pyruvate, respectively, by transamination from glutamate. Asparagine is synthesized by amidation of aspartate, with glutamine donating the NH4. These are nonessential amino acids, and their simple biosynthetic pathways occur in all organisms. Methionine, threonine, lysine, isoleucine, valine, and leucine are essential amino acids in humans and most vertebrates, meaning that oxaloacetate cannot be converted into any of these aminos. However they can be synthesizers in bacteria via biosynthetic pathways that are complex and interconnected.
=== Mid-20th century === Public events in Bryant Park were held through the mid-20th century. For instance, in 1944 during World War II, an aircraft demonstration was held in the park. Outdoor summer concerts in Bryant Park were started in 1948 by Philip Lieson Miller, a musicologist at the New York Public Library. These concerts took place from 12 to 2 p.m. on weekdays from July through September. On October 15, 1969, forty thousand people attended a rally in Bryant Park as part of the nationwide Moratorium to End the War in Vietnam. Another large event, the Big Apple Circus, was proposed to be held in Bryant Park in 1978, but parks commissioner Gordon Davis denied the circus permission to host a show there, since it would have closed off Bryant Park to the public. Plans to build parking garages under Bryant Park also surfaced in the mid-20th century, as a means of relieving parking shortages in Midtown Manhattan. The first such plan was made in 1946 when the city conducted a survey to determine the feasibility of such a garage. Parks commissioner Moses opposed the plan. A parking garage was proposed again in 1958, with plans for 1,200 spaces, though Moses also opposed this proposal. This proposal was backed by the Avenue of the Americas Association. However, though Mayor Robert F. Wagner Jr. supported the proposal, the New York City Planning Commission voted against it in November 1961.
== Genetics == Fibrous protein, long filamentous protein molecule that forms one of the two main classes of tertiary structure protein Fusion protein, protein created through genetic engineering from two or more proteins Globular protein, one of the two main protein classes Protein family, group of evolutionarily related proteins Protein methods, techniques used to study proteins Protein subunit, single protein molecule that assembles with other protein molecules to form a multimeric or oligomeric protein Regulatory protein, term used in genetics to describe a protein involved in regulating gene expression
Sources: en.wikipedia.org
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==== Mechanisms of plasticity ==== To understand mechanisms of activity-dependent plasticity, Sur’s lab used microarray analyses of classic visual plasticity paradigms (dark-rearing and monocular deprivation during the critical period) to discover gene expression changes and microRNAs associated with cortical plasticity. They demonstrated rules of plasticity and the role of specific molecules in implementing these rules. His lab showed that neuronal plasticity is implemented by locally coordinated potentiation and depression of spines, which involves AMPA receptor redistribution via targeted expression of Arc. Together with large-scale synaptic dynamics of V1 neurons during normal development, these findings have demonstrated a fundamental principle, that Hebbian strengthening of coactive synapses and heterosynaptic weakening of adjacent synapses cooperatively mediate neuron-wide plasticity.
Sources: en.wikipedia.org
Epitalon is a synthetic tetrapeptide built from four amino acids: alanine, glutamate, aspartate, and glycine. It is not extracted from a natural source but made in the laboratory by chemical synthesis. Its short length makes it relatively straightforward to produce at high purity.
No naturally occurring free form of the peptide has been described. The four-amino-acid sequence can appear as a fragment within larger proteins, but that is not the same as the intact compound being present as a circulating molecule. Materials used in research are synthetic.
Purity is usually checked by reverse-phase high-performance liquid chromatography, which separates the target peptide from related impurities. Mass spectrometry is commonly used alongside it to confirm molecular mass. Some suppliers also provide amino acid analysis for additional sequence confirmation.
Reversed-phase high-performance liquid chromatography with ultraviolet detection at 214 nanometres is the usual approach. Peak area percentage provides a purity figure relative to other components in the sample. Mass spectrometry is then applied to confirm identity.