Pro-Gly-Pro is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2025-11-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Most published work on selank originates from a small number of research groups in the Russian Federation. A large share of that record appears in Russian-language journals, which limits access for readers who rely on English-indexed databases. Independent replication by laboratories outside the original research network is sparse in publicly available sources. This concentration of origin and language is a frequently noted feature when the compound is summarized in broader reviews of synthetic peptides.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Due to limited data however, more research on potential tolerance and withdrawal effects of moderate doses of doxepin is needed. At these doses of doxepin, dry mouth, an anticholinergic effect, was common (71%), and other side effects such as headache (25%), increased appetite (21%), and dizziness (21%) were also frequently observed, although these adverse effects were notably not significantly more frequent than with placebo in the study in question. In any case, taken together, higher doses of doxepin than very low doses are associated with an increased rate of side effects as well as apparent loss of hypnotic effectiveness with chronic treatment. Doxepin at a dose of 25 mg/day for 3 weeks has been found to decrease cortisol levels by 16% in adults with chronic insomnia and to increase melatonin production by 26% in healthy volunteers. In individuals with neuroendocrine dysregulation in the form of nocturnal melatonin deficiency presumably due to chronic insomnia, very-low-dose doxepin was found to restore melatonin levels to near-normal values after 3 weeks of treatment. These findings suggest that normalization of the hypothalamic–pituitary–adrenal axis and the circadian sleep–wake cycle may be involved in the beneficial effects of doxepin on sleep and insomnia.
== Adverse effects == Adverse effects associated with the MMR vaccine include fever, rash, injection site pain, and, in rare cases, red or purple discolorations on the skin known as thrombocytopenic purpura, or seizures related to fever (febrile seizure).
The journalist and diplomat José Rodríguez Elizondo maintained that from that moment on, a relationship with Peru was consolidated in Chile, inspired by mistrust and prejudice, where the Chileanization carried out by the Patriotic Leagues would be the definitive establishment of mass nationalism, almost Chilean chauvinism, which "led to exalt xenophobic features, fundamentally anti-Peruvian". This perspective, with its nuances, became accessible to many sectors beyond Tarapacá, such as the embarrassing event of Don Ladislao's War, in which accuse of "sold out Peruvian gold" anyone who questioned the action of Minister of War, Ladislao Errázuriz, of mobilizing troops from Santiago to the north, in a farce to attack a fictitious Peruvian enemy, while in reality he wanted the army away from the capital (due to its proximity to the candidate Arturo Alessandri Palma). In addition, innumerable newspapers, starting with the newspapers and magazines of the mainstream press (El Mercurio, El Diario Ilustrado, El Chileno, Zig-Zag and Sucesos), shared a similar idea of the conception of the homeland. In Congress, this thought full of Peruvian-phobic prejudices was personified by the Balmacedista deputy, Anselmo Blanlot, who would end up propagating the idea that the anti-Peruvian violence in the north was truly "imaginary attacks." Peru was seen as barbarism and Chile, it was supposed, light and civilization. Other politicians with anti-Peruvian tendencies were Agustín Edwards Mac-Clure, Víctor Eastman Cox or Rafael Edwards Salas.
=== The Healing Foundation === In 1998, as Treasurer of the British Association of Plastic, Reconstructive, and Aesthetic Surgeons (BAPRAS), Brough and his fellow Trustees established The Healing Foundation. Building on the groundwork laid by the Phoenix Appeal, The Healing Foundation aimed to advance research into surgical and psychological healing techniques for individuals with disfiguring conditions. Various UK medical membership bodies provided support to The Healing Foundation as Partner Member Organisations. These partnerships bolstered the charity's credibility, networking capabilities, and financial resources.These organisations were BAPRAS, the British Association of Aesthetic Surgeons, the British Psychological Society, the Craniofacial Society of Great Britain and Ireland, the British Burns Association, and the British Society for Surgery of the Hand.
Sources: en.wikipedia.org
== Health effects == Due to the elevated levels of nitrites, consuming salted fish increases risk of stomach cancer and nasopharyngeal cancer. The International Agency for Research on Cancer classify salted fish (Chinese-style) as a Group 1 carcinogen.
== June 17, 1915 (Thursday) == Second Battle of Artois — French forces launched a second attack on Vimy Ridge but failed to take it. British pilot Reginald Warneford died along with American journalist Henry Beach Newman after crashing a new Farman biplane during takeoff from Buc, France, just shortly after a ceremony in Paris in which he received the French Legion of Honour for shooting down a German airship. Former U.S. President William Howard Taft became president of the League to Enforce Peace when it was established during a peace convention at Independence Hall in Philadelphia. Other founding members of the organization included Elihu Root, Alexander Graham Bell, Rabbi Stephen Samuel Wise, U.S. Chamber of Commerce executives James Gibbons and Edward Filene, Harvard University President A. Lawrence Lowell, and former U.S. Cabinet member and diplomat Oscar Straus. The baseball stadium Bosse Field officially opened in Evansville, Indiana, the first municipally owned stadium in the United States. It is the third oldest operating ballpark after Fenway Park and Wrigley Field. Born: Mario Echandi Jiménez, 33rd President of Costa Rica from 1958 to 1962; in San José, Costa Rica (d. 2011) David "Stringbean" Akeman, American country musician, member of band for the TV variety show Hee Haw and a member of the Grand Ole Opry; in Annville, Kentucky, United States (d. 1973, murdered) Died: Thomas Jordan Jarvis, 79, American politician, 44th Governor of North Carolina (b. 1836)
=== The "flow" === In the 1970s Csikszentmihalyi started to study flow, a state of absorption where one's abilities are well-matched to the demands at-hand. Flow is characterized by intense concentration, loss of self-awareness, a feeling of being perfectly challenged (neither bored nor overwhelmed), and a sense "time is flying". Flow is intrinsically rewarding; it can also assist in the achievement of goals (e.g., winning a game) or improving skills (e.g., becoming a better chess player). Anyone can experience flow, in different domains, such as play, creativity, and work. Flow is achieved when the challenge of the situation meets one's personal abilities. A mismatch of challenge for someone of low skills results in a state of anxiety; insufficient challenge for someone highly skilled results in boredom. The effect of challenging situations means that flow is often temporarily exciting and variously stressful, but this is considered eustress, which is also known as "good" stress. Eustress is arguably less harmful than chronic stress, although the pathways of stress-related systems are similar. Both can create a "wear and tear" effect; however, the differing physiological elements and added psychological benefits of eustress might well balance any wear and tear experienced. Csikszentmihalyi identified nine indicator elements of flow: 1. Clear goals exist every step of the way, 2. Immediate feedback guides one's action, 3. There is a balance between challenges and abilities, 4. Action and awareness are merged, 5. Distractions are excluded from consciousness, 6.
=== Precursors to chlorinated cyanurates === Cyanuric acid is mainly used as a precursor to N-chlorinated cyanurates, which are used to disinfect water. The dichloro derivative is prepared by direct chlorination:
=== In vitro virus high-throughput sequencing === A method has been developed to analyze full sets of protein interactions using a combination of 454 pyrosequencing and an in vitro virus mRNA display method. Specifically, this method covalently links proteins of interest to the mRNAs encoding them, then detects the mRNA pieces using reverse transcription PCRs. The mRNA may then be amplified and sequenced. The combined method was titled IVV-HiTSeq and can be performed under cell-free conditions, though its results may not be representative of in vivo conditions.
Sources: en.wikipedia.org
East Tennesseans felt the state had squandered the proceeds from the sale of land in the Hiwassee District (1819) on a failed state bank, rather than on badly needed internal improvements. It wasn't until 1828 that a steamboat, the Atlas, managed to navigate Muscle Shoals and make it upriver to Knoxville. River improvements in the 1830s allowed Knoxville semi-annual access to the Mississippi, though by this time the city's merchants had shifted their focus to railroad construction.
Prescientific forms of medicine, now known as traditional medicine or folk medicine, remain commonly used in the absence of scientific medicine and are thus called alternative medicine. Alternative treatments outside of scientific medicine with ethical, safety and efficacy concerns are termed quackery or being based on fringe science.
== Contraindications == Benzodiazepines require special precaution if used in the elderly, during pregnancy, in children, alcohol or drug-dependent individuals and individuals with comorbid psychiatric disorders. Phenazepam should not be taken with alcohol or any other CNS depressants. Phenazepam should not be used therapeutically for periods of longer than one month including tapering on and off the drug as recommended for any benzodiazepine in the British national formulary. Some patients may require longer term treatment. Phenazepam was found to be a component in some "herbal incense" mixtures in Australia and New Zealand in 2011, namely "Kronic". The particular product variety was withdrawn from the market shortly after and replaced with a new formulation.
== Assembly methods == A persistent problem within tissue engineering is mass transport limitations. Engineered tissues generally lack an initial blood supply, thus making it difficult for any implanted cells to obtain sufficient oxygen and nutrients to survive, or function properly.
Sources: en.wikipedia.org
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.