Selank raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-04-26. Anything still debated is marked as such rather than presented as settled.
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.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
The only confirmed isotope of oganesson, 294Og, has much too short a half-life to be chemically investigated experimentally. Therefore, no compounds of oganesson have been synthesized yet. Nevertheless, calculations on theoretical compounds have been performed since 1964. It is expected that if the ionization energy of the element is high enough, it will be difficult to oxidize and therefore, the most common oxidation state would be 0 (as for the noble gases); nevertheless, this appears not to be the case. Calculations on the diatomic molecule Og2 showed a bonding interaction roughly equivalent to that calculated for Hg2, and a dissociation energy of 6 kJ/mol, roughly 4 times of that of Rn2. Most strikingly, it was calculated to have a bond length shorter than in Rn2 by 0.16 Å, which would be indicative of a significant bonding interaction. On the other hand, the compound OgH+ exhibits a dissociation energy (in other words proton affinity of oganesson) that is smaller than that of RnH+. The bonding between oganesson and hydrogen in OgH is predicted to be very weak and can be regarded as a pure van der Waals interaction rather than a true chemical bond. On the other hand, with highly electronegative elements, oganesson seems to form more stable compounds than for example copernicium or flerovium. The stable oxidation states +2 and +4 have been predicted to exist in the fluorides OgF2 and OgF4. The +6 state would be less stable due to the strong binding of the 7p1/2 subshell. This is a result of the same spin–orbit interactions that make oganesson unusually reactive.
A historian with a very strong work ethic, Peukert believed that history "belonged to everybody", not just the historians, and was very energetic in attempting to break down barriers to interest the public in history by settling up exhibitions about Alltagsgeschichte in the Third Reich. In 1980, Peukert planned the historical exhibition at the Old Synagogue of Essen on the subject "Resistance and Persecution in Essen 1933-1945". In 1984, Peukert won the Heinz Maier-Leibnitz Prize for his habilitation on youth policy in Germany in late 19th and early 20th centuries. Moving beyond the subject of resistance (Widerstand), Peukert became interested in "oppositionality" (Widerständigkeit) in everyday life in Nazi Germany. Peukert was especially interested in the Edelweiss Pirates, a group of working class teenagers in Cologne and the other cities of the Rhineland who formed a distinctive anti-Nazi subculture, and who often fought the Hitler Youth. Another related area of interest for Peukert was resistance, opposition and dissent in the Third Reich. Peukert developed a pyramid model starting with "nonconformity" (behavior in private that featured partial rejection of the Nazi regime) running to "refusal of co-operation" (Verweigerung) to "protest", and finally to Widerstand (resistance), which involved total rejection of the Nazi regime. In particular, Peukert looked at how in "everyday life" in Nazi Germany, aspects of both "normality" and "criminality" co-existed with another.
Cirrhosis can take quite a long time to develop, and symptoms may be slow to emerge. Some early symptoms include tiredness, weakness, loss of appetite, weight loss, and nausea. Early signs may also include redness on the palms known as palmar erythema. People may also feel discomfort in the right upper abdomen around the liver. As cirrhosis progresses, symptoms may include neurological changes affecting both the peripheral and central nervous systems, disrupting the neurotransmission within the brain and causing neuromuscular fatigue. This can consist of cognitive impairments, confusion, memory loss, sleep disorders, and personality changes. Steatorrhea or presence of undigested fats in stool is also a symptom of cirrhosis. Worsening cirrhosis can cause a build-up of fluid in different parts of the body, such as the legs (edema) and abdomen (ascites). Other signs of advancing disease include itchy skin, bruising easily, dark urine, and yellowing of the skin.
In a 1951 letter to the publisher Milton Waldman (1895–1976), Tolkien wrote about his intentions to create a "body of more or less connected legend", of which "[t]he cycles should be linked to a majestic whole, and yet leave scope for other minds and hands, wielding paint and music and drama". The hands and minds of many artists have indeed been inspired by Tolkien's legends. Personally known to him were Pauline Baynes (Tolkien's favourite illustrator of The Adventures of Tom Bombadil and Farmer Giles of Ham) and Donald Swann (who set the music to The Road Goes Ever On). Queen Margrethe II of Denmark created illustrations to The Lord of the Rings in the early 1970s. She sent them to Tolkien, who was struck by the similarity they bore in style to his own drawings. Tolkien was not implacably opposed to the idea of a dramatic adaptation, however, and sold the film, stage and merchandise rights of The Hobbit and The Lord of the Rings to United Artists in 1968. United Artists never made a film, although the director John Boorman was planning a live-action film in the early 1970s. In 1976 the rights were sold to Tolkien Enterprises, a division of the Saul Zaentz Company, and the first film adaptation of The Lord of the Rings was released in 1978 as an animated rotoscoping film directed by Ralph Bakshi with screenplay by the fantasy writer Peter S. Beagle. It covered only the first half of the story of The Lord of the Rings.
Sources: en.wikipedia.org
Buthionine sulfoximine (BSO) is a sulfoximine derivative which reduces levels of glutathione and is being investigated as an adjunct with chemotherapy in the treatment of cancer. The compound inhibits gamma-glutamylcysteine synthetase, the enzyme required in the first step of glutathione synthesis. Buthionine sulfoximine may also be used to increase the sensitivity of parasites to oxidative antiparasitic drugs.
=== Awards and honours === Knowles was elected a Fellow of the Royal Society (FRS), a Fellow of the American Academy of Arts and Sciences (FAAAS) in 1982, and member of American Philosophical Society in 1988, the American Association for the Advancement of Science, and a Foreign Associate of the National Academy of Sciences. Among his awards are the Royal Society of Chemistry's Charmian Medal, the Bader Award, the Repligen Corporation Award in Chemistry of Biological Processes, the Prelog Medal, the Robert A. Welch Award in Chemistry, the Arthur C. Cope Scholar Award, and the Nakanishi Prize. He was awarded the Davy Medal of the Royal Society, and was an Honorary Fellow of Balliol College and of Wadham College, Oxford. He held honorary degrees from the University of Edinburgh and the Eidgenössische Technische Hochschule in Zürich. He was appointed Order of the British Empire in the 1993 Birthday Honours. He was elected one of nine Trustees of the Howard Hughes Medical Institute in 1998.
In fact neon is the most electronegative element, but the Pauling scale cannot measure its electronegativity because it does not form covalent bonds with most elements. An element's electronegativity varies with the identity and number of the atoms it is bonded to, as well as how many electrons it has already lost: an atom becomes more electronegative when it has lost more electrons. This sometimes makes a large difference: lead in the +2 oxidation state has electronegativity 1.87 on the Pauling scale, while lead in the +4 oxidation state has electronegativity 2.33.
Sources: en.wikipedia.org
On 15 April 1944, VIII Fighter Command began "Operation Jackpot", attacks on Luftwaffe fighter airfields. As the efficacy of these missions increased, the number of fighters at the German airbases fell to the point where they were no longer considered worthwhile targets. On 21 May, targets were expanded to include railways, locomotives, and other rolling stock used by the Germans to transport materiel and troops, in missions dubbed "Chattanooga". The P-51 excelled at this mission, although losses were much higher on strafing missions than in air-to-air combat, partially because the Mustang's Merlin engine, being liquid cooled, was vulnerable to radiator and coolant line damage from small-arms gunfire. On the other hand, the Mustang's stablemate, the Republic P-47 Thunderbolt, being powered by an air-cooled radial engine, could usually shrug off small-arms fire, and thus was regularly tasked with ground-strafing missions.
The clearance rate, or the rate at which the carrier protein is broken down, for GHBP alone is much faster than when it is bound to its ligand. Additionally, current literature provides evidence that the carrier-protein prolongs the half-life of growth hormone through its binding with the ligand. One purpose of GHBP can be inferred: to maintain the level of GH in the blood, as roughly half of its concentration is complexed with GHBP. Yet this could be confounded by the fact that GH binding to GHBP prevents the ligand from binding to GHR and ultimately proteolytic activity. Another function is that GHBP displays competitive inhibition for GH against the GHR receptor. Studies elucidate another aspect of GHBP physiological role: The proteolytic cleavage activity that forms GHBP ultimately regulates GHR production in humans as well as rats. If there is low GHBP concentration then there are high levels of GHR expression. Conversely, high levels of GHBP protein show negative correlation with levels of growth hormone receptor expression.
Strength training typically incorporates strengthening the muscles of the body. This means that the tension of the muscle when at rest will ordinarily be increased. This also influences the length of the muscle in a relationship known as length-tension. This length-tension of the muscle influences the standard position of the joints it connects to via the tendons. If it is too tight or too loose then the respective joints risk being pulled or falling out of their optimum position which is known as being centrated (centered). The optimum positioning of a joint is gained and maintained by the muscles which influence it, including the agonists and antagonists, being of the correct length-tension and in the appropriate balance of strength with each other. In turn, the optimum joint position means that the muscles length-tension is regulated more efficiently with greater levels of control. Due to this reciprocal relationship between the muscles and joints, strength training programmes seek to ensure that the muscles are not strengthened in an excessive and disharmonious way which will lead to poor joint alignment (decentration). Where poor joint alignment does occur the amount of force the muscles can apply is reduced, movement control (agility) is reduced, and injury risk is increased especially in regard to wear and tear injuries. Forms of exercise which seek to specifically improve joint alignment, and thereby increase joint stability and flexibility, include those which emphasise balance and proprioception e.g.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.