Pineal peptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-03. Anything still debated is marked as such rather than presented as settled.
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.
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.
Because epitalon has no pharmacopoeial monograph, quality assessment depends on supplier documentation and independent testing. Certificates of analysis typically report a purity figure from a single chromatographic run, a measured mass and sometimes an appearance description, but methods and acceptance criteria are not harmonised across vendors. Third-party laboratories can repeat identity and purity measurements, and mismatches between labelled and measured peptide content have been described for research peptides generally. What constitutes adequate identity confirmation for a molecule of this size stays an open question, since mass agreement alone does not separate closely related sequences.
Identity testing for epitalon relies on reversed-phase high-performance liquid chromatography for purity and mass spectrometry for mass confirmation. Because the sequence contains no tryptophan or tyrosine, ultraviolet detection at 280 nanometres is insensitive, so chromatographic methods usually monitor absorbance near 214 nanometres, where the peptide backbone absorbs. Electrospray ionisation or matrix-assisted laser desorption/ionisation then checks the intact mass against the expected value near 390 daltons. Peptide mapping or amino acid analysis after acid hydrolysis can supplement these measurements, although such confirmatory work is seldom reported on commercial certificates of analysis.
Stability of the tetrapeptide follows ordinary peptide chemistry rather than any unusual structural feature. The aspartate-glycine pair is prone to aspartimide formation under mildly basic or neutral conditions, and deamidation can follow, altering both mass and chromatographic retention. Dry lyophilised powder kept at or below minus twenty degrees Celsius is the usual handling recommendation, with repeated freeze-thaw cycles avoided. Once dissolved in neutral aqueous buffer, degradation proceeds over days to weeks depending on pH and temperature, while acidic conditions generally slow the aspartimide route. A formal stability-indicating study has not been published in the indexed literature.
| 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 compound is described in the literature as a derivative of epithalamin, a preparation obtained from bovine pineal tissue. Work on this peptide family was carried out mainly by a research group in Saint Petersburg beginning in the 1980s, and the substance was later registered for clinical use in Russia under the name Epitalon. Outside that region it is generally treated as a research chemical rather than an approved medicine. Statements about its biological activity rest on a relatively small number of studies, and independent replication remains limited.
In its supplied form epitalon is a white to off-white powder, usually lyophilized and often hygroscopic. It dissolves readily in water and in aqueous buffers, and it is commonly handled as the acetate or trifluoroacetate salt to improve stability during purification and drying. The amide backbone is labile in aqueous media, so solutions are less durable than the dry solid. Handling notes in the chemical literature therefore emphasize keeping the powder dry, cool and shielded from light until it is dissolved.
Epitalon is a synthetic tetrapeptide whose sequence is alanine-glutamate-aspartate-glycine, written in single-letter code as AEDG. The four residues are joined by three peptide bonds, giving a linear backbone with no branching and no disulfide bridges. Its calculated molecular mass for the free form is approximately 390.3 daltons, a figure that rises when the compound is supplied as an acetate or trifluoroacetate salt. Because the chain is short, the molecule is defined entirely by its residue order rather than by any folded three-dimensional structure.
Short peptides such as AEDG are normally supplied as a freeze-dried solid and are kept dry, cold, and shielded from light. Holding at minus twenty degrees Celsius is common for the long term, while a refrigerator suffices for brief periods before use. The material takes up moisture to some degree, so containers should stay sealed and be allowed to reach room temperature before opening, which limits condensation on the contents. Repeated warming and cooling of a single container is discouraged because it admits water and can lower the amount of intact peptide.
Dissolution is usually performed in water or a suitable aqueous buffer, and the resulting liquid is divided into single-use portions before freezing. Freeze-thaw cycling is a recognised source of loss for short peptides, since each cycle can encourage aggregation or adsorption onto container walls. Working solutions are generally kept cold and used within a short window, although published stability data specific to epitalon are thin. Containers should be marked with concentration and date, and solutions examined for cloudiness before use.
The compound is generally described as a synthetic analogue of a fragment isolated from a pineal gland extract. Researchers associated with the Saint Petersburg Institute of Bioregulation and Gerontology introduced it during the 1980s and 1990s while studying short peptides from animal tissue. The original extract, called epithalamin, is a heterogeneous mixture, whereas epitalon is a single defined sequence. That distinction matters because findings reported for the extract are not automatically findings about the pure tetrapeptide, and claims about broader biological effects remain a separate question from the chemical identity described here.
Residue composition is the property that most cleanly separates verified material from mislabelled samples. Alanine, glutamate, aspartate and glycine appear in that order from the N-terminus, and the two acidic residues sit in the middle of the chain. Because the peptide is short, it can be produced by solid-phase synthesis and characterised by mass spectrometry without ambiguity. Any reported sample whose measured mass departs substantially from 390 daltons is a different compound or a degraded mixture rather than epitalon.
Epitalon is a synthetic tetrapeptide whose four residues are alanine, glutamate, aspartate and glycine, commonly abbreviated AEDG. Its molecular formula is C14H22N4O9 and its monoisotopic mass is near 390.35 daltons. The peptide carries two acidic side chains, so it is neutral to negatively charged in most aqueous buffers. Published reference summaries usually list it under both spellings, epitalon and epithalon, and treat the two names as the same material.
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.
Purity assessment of peptide reagents normally relies on reversed-phase high-performance liquid chromatography. A gradient of acetonitrile in water with trifluoroacetic acid, paired with a C18 stationary phase, separates the target tetrapeptide from truncated sequences and deletion analogues. Detection at 214 nanometres exploits absorbance of the peptide backbone, since the molecule contains no aromatic residue. Results are expressed as a percentage of total peak area. Values above ninety-five percent are typical for research-grade material, although reporting conventions vary between suppliers.
action potential The local change in voltage that occurs when the membrane potential of a specific location along the membrane of a cell rapidly depolarizes, such as when a nerve impulse is transmitted between neurons.
Nucleotide substitution (e.g., 76A>T) – The number is the position of the nucleotide from the 5' end; the first letter represents the wild-type nucleotide, and the second letter represents the nucleotide that replaced the wild type. In the given example, the adenine at the 76th position was replaced by a thymine. If it becomes necessary to differentiate between mutations in genomic DNA, mitochondrial DNA, and RNA, a simple convention is used. For example, if the 100th base of a nucleotide sequence mutated from G to C, then it would be written as g.100G>C if the mutation occurred in genomic DNA, m.100G>C if the mutation occurred in mitochondrial DNA, or r.100g>c if the mutation occurred in RNA. Note that, for mutations in RNA, the nucleotide code is written in lower case. Amino acid substitution (e.g., D111E) – The first letter is the one letter code of the wild-type amino acid, the number is the position of the amino acid from the N-terminus, and the second letter is the one letter code of the amino acid present in the mutation. Nonsense mutations are represented with an X for the second amino acid (e.g. D111X). Amino acid deletion (e.g., ΔF508) – The Greek letter Δ (delta) indicates a deletion. The letter refers to the amino acid present in the wild type and the number is the position from the N terminus of the amino acid were it to be present as in the wild type.
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== Other Branded Generics == Biqi is the brand name for its generic OTC anti-diarrhea pharmaceutical. The Company obtained approval to manufacture and sell Biqi in November 1999. Zaiqi is the brand name for the company's azithromycin granules antibiotics for the treatment of infections. Zaike is the brand name for its cefaclor in dry suspension antibiotics for the treatment of infections. Simcere Kechuanning is the brand name for Simcere Pharmaceutical's OTC herbal medicine used for the treatment of coughs. It comes in oral liquid and tablet formulations. Zaikang is the brand name for its OTC compound zinc gluconate and ibuprofen granules for the treatment of cold symptoms, such as fever, nasal congestion, running nose and sneezing. Faneng is the brand name for the company's alfacalcidol soft capsules for the treatment of osteoporosis.
Physical side effects included pupil dilation, tingling, trembling, numbness, sweating, lightheadedness, athetosis, slight nausea, and increased heart rate and blood pressure. In addition to parenteral DMT, Shulgin described the effects of oral DMT plus harmaline or in some cases Peganum harmala seeds in TiHKAL. The effects were reported to include closed-eye imagery such as colors, infinitely repeated and wavy sheets of patterns, and kaleidoscopic images, visual changes like brighter colors and patterns and distortions, music enhancement, time distortion, clarity, insights, intoxication, emotional changes, feeling alive and excited, depression, despair, and feeling psychotic. Other effects included difficulty focusing on thoughts, short-term memory disruption, feeling cold, nausea, gait impairment or difficulty walking, and an afterglow. The preceding effects are variably due to both DMT and harmaline, with harmaline also producing its own hallucinogenic effects at sufficiently doses, for instance 150 mg or more.
Sources: en.wikipedia.org
So it was proposed that succinyl amino acid derivative should be an ACE inhibitor and succinyl-L-proline was found to be such an inhibitor. It was also known that the nature of penultimate amino acid residue of a peptide substrate for ACE influences binding to the enzyme. The acyl group of the carboxyalkanoyl amino acid binds the zinc ion of the enzyme and occupies the same position at the active site of ACE as the penultimate. Therefore, the substituent of the acyl group might also influence binding to the enzyme. A 2-methyl substituent with D configuration was found to enhance the inhibitory potency by about 15 fold of succinyl-L-proline. Then the search for a better zinc-binding group started. Replacement of the succinyl carboxyl group by nitrogen-containing functionalities (amine, amide or guanidine) did not enhance inhibitory activity. However a potency breakthrough was achieved by the replacement of the carboxyl group with a sulfhydryl function (SH), a group with greater affinity for the enzyme bound zinc ion. This yielded a potent inhibitor that was 1000 times more potent than succinyl-L-proline. The optimal acyl chain length for mercaptoalkanoyl derivates of proline was found to be 3-mercaptopropanoyl-L-proline, 5 times greater than that of 2-mercaptoalkanoyl derivates and 50 times greater than that of 4-mercaptoalkanoyl derivates. So the D-3-mercapto-2-methylpropanoyl-L-proline or Captopril was the most potent inhibitor.
== Accords == On February 19, 2015, representatives from the Malian government and the Coordination of Azawad Movements (CMA) agreed upon a new document, including the cessation of hostilities, as negotiations to end the broader war continued in Algiers. On March 1, a mediation agreement was proposed by Algeria, which was accepted by Mali and pro-government militias. The CMA asked for some time to consider the agreement, as there were no propositions for autonomy or federalism for northern Mali, which angered a large portion of Tuareg rebels. The CMA announced their refusal to sign the agreement on April 10. On April 27, the pro-government GATIA and Arab Movement of Azawad (MAA) captured Menaka, initiating new clashes between Tuareg rebels and the pro-government militias. On May 10, the CMA initialized the agreement, but did not sign the text. The peace agreement was signed on May 15 in Bamako by the Malian government, representatives of pro-government militias, and representatives from Algeria, Burkina Faso, Mauritania, Niger, Nigeria, Chad, the African Union, the United Nations, ECOWAS, the Organisation of Islamic Cooperation, the European Union, and France. No CMA representatives were present for the signing on May 15. That same day, fighting broke out near Menaka. Under pressure from international organizations, the CMA finally signed the agreement in Bamako on June 20. The CMA's representative was Sidi Brahim Ould Sidati, a leader of the MAA.
== Adverse effects == Like other fluoroquinolones, difloxacin causes arthropathy in immature growing animals, particularly dogs. Otherwise, it is very well tolerated. The most common adverse effects are gastrointestinal effects such as vomiting, diarrhea and anorexia, even in overdose. Only supportive measures, and not additional treatment, are recommended for management of overdose or toxicity as the reactions are self-limiting. Contraindications include small and medium breeds of dogs that are less than 8 months old; large breeds less than 12 months old; giant breeds less than 18 months old; those with suspected CNS disorders; and hypersensitivity to difloxacin or any other fluoroquinolone.
Infants of mothers with inverted nipples can still achieve a good latch with perhaps a little extra effort. For some women, the nipple may easily become erect when stimulated. Other women may require modified breastfeeding techniques, and some may need extra devices, such as nipple shells, modified syringes, or breast pumps to expose the nipple. La Leche League and Toronto Public Health offer several techniques to use during pregnancy or even in the early days following birth that may help to bring a flat or inverted nipple out.
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.
The molecule lacks aromatic residues, so it absorbs weakly near 280 nanometres, the wavelength applied to many other peptides. The peptide bond absorbs strongly below 220 nanometres, making 214 nanometres a practical compromise. Gradient methods must therefore use mobile phases with low ultraviolet absorbance to keep the baseline clean.