Everything below concerns proteolysis. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-01-07. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Derived from the seven-residue sequence |
| Molecular weight | About 751.9 g/mol | Average mass; the monoisotopic value is slightly lower |
| Residue count | Seven amino acids | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Parent compound | Tuftsin (Thr-Lys-Pro-Arg) | Selank extends tuftsin at the C-terminus |
| Compound class | Synthetic short peptide | Studied in a research setting; not a licensed drug in most markets |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
(CH2CH2)O + PCl3 → Cl–CH2CH2–OPCl2 2 (CH2CH2)O + PCl3 → (Cl–CH2CH2–O)2PCl 3 (CH2CH2)O + PCl3 → Cl–CH2CH2–O)3P The reaction product of ethylene oxide with acyl chlorides in the presence of sodium iodide is a complex iodoethyl ester:
Norbert Elias; (1897-1990) sociologist especially famous for theory of civilising/decivilising processes; was deeply involved in the German Zionist movement, and acted as one of the leading intellectuals within the German-Jewish youth movement "Blau-Weiss" (Blue-White). Elias' most famous work is The Civilizing Process Samantha Ellis is an Iraqi Jewish British playwright and writer best known for her books How to be a Heroine, Chopping Onions on My Heart, and her play How to Date a Feminist. Richard Ellmann literary scholar and biographer Aaron Esterson (23 September 1923 – 15 April 1999) prolific author and psychiatrist who was one of the founders of the Philadelphia Association along with R. D. Laing, with whom he wrote Sanity, Madness, and the Family. He wrote four other scholarly texts on psychiatry and existentialism as well as countless academic papers and monographs. Hans Eysenck (4 March 1916 – 4 September 1997); author of over fifty books and numerous academic papers; of German Jewish maternal lineage; psychologist best remembered for his work on intelligence and personality, although he worked on other issues in psychology. At the time of his death, Eysenck was the most frequently cited living psychologist in the peer-reviewed scientific journal literature. Henry Ezriel (c1910-1985) was a Kleinian analyst and author who pioneered group analysis at the Tavistock Clinic; best known as the originator of one of the Malan triangles; worked alongside W. R. Bion as consultant psychiatrist to the Tavistock.
=== Movement === In addition to the formation of lamellipodia and filopodia, intracellular concentration and cross-talk between different Rho proteins drives the extensions and contractions that cause cellular locomotion. Sakumura et al. proposed a model based on differential equations that helps explain the activity of Rho proteins and their relationship to motion. This model encompassed the three proteins Cdc42, RhoA, and Rac. Cdc42 was assumed to encourage filopodia elongation and block actin depolymerization. RhoA was considered to encourage actin retraction. Rac was treated to encourage lamellipodia extension but block actin depolymerization. These three proteins, although significantly simplified, covered the key steps in cellular locomotion. Through various mathematical techniques, solutions to the differential equations that described various regions of activity based on intracellular activity were found. The paper concludes by showing that the model predicts that there are a few threshold concentrations that cause interesting effects on the activity of the cell. Below a certain concentration, there is very little activity, causing no extension of the arms and feet of the cell. Above a certain concentration, the Rho protein causes a sinusoidal oscillation much like the extensions and contractions of the lamellipodia and filopodia. In essence, this model predicts that increasing the intracellular concentration of these three key active Rho proteins causes an out-of-phase activity of the cell, resulting in extensions and contractions that are also out of phase.
=== First confirmed cases: May–June 2022 === On 12 May 2022, the North Korean government declared a "severe national emergency", after samples from an unspecified number of people tested positive for COVID-19. This marked the first time that North Korea had publicly acknowledged the existence of COVID-19 cases in the country. The Korean Central News Agency stated that Supreme Leader Kim Jong Un had called an emergency meeting of the Politburo of the Workers' Party of Korea after learning of the samples, which were sourced from residents of Pyongyang and had symptoms "consistent with" the Omicron variant. The Politburo recommended the implementation of a "maximum" emergency quarantine, to include nationwide lockdowns, border restrictions, and restrictions on group sizes in workplaces. During the politburo meeting, the previous anti-pandemic strategy was criticised. NK News reported that the entire country had been placed under a lockdown two days prior, though farmers in border regions close to South Korea were seen still tending the fields. It was later reported by state media that at least one North Korean died after testing positive, and that 187,800 people are now under quarantine due to "fever". On 13 May, Kim Jong Un held a meeting at the State Emergency Epidemic Prevention Headquarters, where he called for further anti-pandemic work, lockdowns, and isolation of suspected cases. The effort to stop the spread was declared to be a supreme task of the party.
=== Acid coagulants === Glucono delta-lactone (GDL) is a naturally occurring organic acid also used in cheesemaking, this coagulant produces a very fine textured tofu that is almost jelly-like. It is used especially for "silken" and softer tofus and confers a faint sour taste to the finished product. GDL is derived from glucose and takes the form of a white powder at room temperature. Its molecular structure contains a six-membered heterocyclic ring that is hydrolyzed upon contact with water, slowly converting GDL to gluconic acid. When added to soy milk, it gradually lowers the pH and causes proteins to coagulate evenly throughout the mixture, forming a single, smooth gel that is free of air gaps and that resists breaking during transportation. Using GDL as a coagulant, silken tofu can be formed directly in its container, as it does not require pressing. This acid coagulant is also commonly used together with calcium sulfate to give soft tofu a smooth, tender texture. Other edible acids can be used. Though they can affect the taste of the tofu more, and vary in density and texture, acids such as acetic acid (vinegar) and citric acid (such as lemon juice), can also be used to coagulate soy milk and produce tofu.
Sources: en.wikipedia.org
In March 1973, the Argentine government and the Union Argentina de Rugby had a great conflict: the government contested to UAR the permit given to San Isidro Club to visit South Africa, and forced the federal committee of UAR to resign. A new committee was elected on 24 April 1973. In November the government also forbade all visits to South Africa by any Argentine team and any visit of a South African team into Argentina. This ban remained until 1991. South Africa was the indirect cause of the 1976 Olympic boycott. A New Zealand rugby union tour of South Africa prompted African countries to demand that the New Zealand Olympic team be excluded from the games. The IOC demurred on the grounds that rugby union was not an Olympic sport and the New Zealand Rugby Union was not affiliated to the New Zealand Olympic Committee. Of 28 African invitees, 26 boycotted the Games, joined by Iraq and Guyana. In February 1977, Danie Craven flew to London to plead for South African rugby's reintegration into the international scene, and to make a last ditch attempt to save the Springboks' scheduled tour of the British Isles in 1978, and the British Lions tour of South Africa in 1980.
=== Harness with buoyancy compensation === The AP Valves Mk4 Jump Jacket is a harness with integral buoyancy jacket specifically designed for commercial diving work with helmets and bells. There is a direct feed to the jacket from the main air supply, via the helmet side-manifold block, from the pneumo line and from bailout, and a system which allows the diver's pneumo to be directly connected to another diver's helmet as an emergency air supply. The harness supports a single or twin cylinder bailout set, allows buoyancy control from slightly negative through neutral, to sightly positive, and has a safety harness for retaining the helmet.The Jump Jacket also serves as a recovery harness for rescues to the bell, and has front and back lifting points.
== Emitters == Several different emitter configurations have been used for FD emitters, such as single tips, sharp blades and thin wires. Single metal tips can be made from etching wires either by periodically dipping them into molten salts or by electrolysis in aqueous solutions. Compared to other emitter types, the single tips have the advantage that they can reach the highest field strengths. In addition, well-defined geometric shape of a single tip allows accurate calculation of the potential distribution in the space between the tip and the counter electrode. For blades used as emitters, their ruggedness under the high electric field is one of their advantages. Different thin wires were also used as emitters, such as platinum wires and tungsten wires. Platinum wires are fragile, and tungsten wires are much more stable than platinum wires. Among those emitters, carbon-microneedles tungsten wires are the most widely used emitters in FD mass spectrometry.
=== Sales === The Valve Index headset, controllers, and base stations sold out in the US, Canada, and Europe within a week of the Alyx announcement. By mid-January 2020, they were sold out in all 31 regions. According to Superdata, Valve sold 103,000 Index units in the fourth quarter of 2019 as a result of the Alyx announcements, compared to the total 149,000 sold throughout 2019, and the Index was the highest-selling VR headset for PCs during that quarter. Though Valve had expected to supply several Index orders in time for the release of Alyx, the COVID-19 pandemic limited their supply chain. Valve's Greg Coomer said Valve knew many people would not play Alyx on launch and that its audience was "relatively small right now". Newell described it as a "forward investment" into long-term technologies. In 2021, PCGamesN wrote that though it was "artfully crafted", Alyx had had little cultural impact. As of December 2024, Alyx had sold more than two million copies.
The chief cells of the parathyroid glands sense the amount of calcium in the blood, and release the calcium-increasing hormone parathyroid hormone (PTH) accordingly to correct or maintain normal blood calcium levels. It therefore regulates calcium metabolism as part of the endocrine system. PTH raises calcium levels by releasing calcium from bone storage, as well as retaining calcium from the urine, and alerts the intestines to absorb more calcium from ingested nutrients. Too much of either hormone can be an indicator of disease.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.
Tuftsin contains four residues, while selank carries an additional Pro-Gly-Pro segment at the carboxyl end. That extension is intended to reduce enzymatic cleavage. Comparative pharmacokinetic data in humans remain limited.
No single receptor target is widely accepted as the definitive mediator of the reported effects. Proposed contributors include GABAergic modulation, shifts in monoamine turnover, and altered neuropeptide degradation. The mechanism is treated in the literature as unresolved.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.