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This page was last updated on 2025-12-15 and is reviewed periodically as new material appears.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
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.
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.
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.
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.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
== Bibliography == Move That Mountain (1976), ISBN 978-0-88270-164-6 Eight Keys to Success (1980), ISBN 978-0-89221-071-8 I Was Wrong (1996), ISBN 978-0-7852-7425-4 Prosperity and the Coming Apocalypse (1998), ISBN 978-1-4185-5422-4 The Refuge: The Joy of Christian Community in a Torn-Apart World (2000), ISBN 978-1-4185-5423-1 Time Has Come: How to Prepare Now for Epic Events Ahead (2014), ISBN 978-1-61795-134-3 You Can Make It: God's Faithfulness in Dark Times-Past, Present and Future (2021), ISBN 978-1-63641-047-0
Since this series was only discovered and studied in 1947–1948, its nuclides were never given historic names. Each of the other series have many of their nuclides given historical names. This series has an isotope of radon only produced in a rare branch (not shown in the illustration) but not in the main decay sequence. Other series produce radon in the main decay sequence, which, if occurring in mineral, would tend to migrate through the mineral and be released as radioactive gas. This series ends in thallium (or, practically speaking, bismuth) rather than lead. Its parent nuclides are essentially extinct, explaining why the series was discovered much later, after the development of artificial nucleosynthesis. Each of the other series have primordial parent nuclides. The total energy released from neptunium-237 to thallium-205, including the energy lost to neutrinos, is 49.29 MeV; from californium-249, 66.87 MeV. As the energy of the final step from bismuth to thallium, though known, will not be available until the inconceivable future, it may be better to quote the figures 46.16 MeV and 63.73 MeV to bismuth-209.
To determine the pore diameter, physical methods such as porosimeter (mercury, liquid-liquid porosimeter and Bubble Point Test) are also used, but a certain form of the pores (such as cylindrical or concatenated spherical holes) is assumed. Such methods are used for membranes whose pore geometry does not match the ideal, and we get "nominal" pore diameter, which characterizes the membrane, but does not necessarily reflect its actual filtration behavior and selectivity. The selectivity is highly dependent on the separation process, the composition of the membrane and its electrochemical properties in addition to the pore size. With high selectivity, isotopes can be enriched (uranium enrichment) in nuclear engineering or industrial gases like nitrogen can be recovered (gas separation). Ideally, even racemics can be enriched with a suitable membrane. When choosing membranes selectivity has priority over a high permeability, as low flows can easily be offset by increasing the filter surface with a modular structure. In gas phase filtration different deposition mechanisms are operative, so that particles having sizes below the pore size of the membrane can be retained as well.
Sources: en.wikipedia.org
=== Zebrafish === Upon injury, zebrafish (Danio rerio) cardiomyocytes have been found to have the capability to differentiate and subsequently rapidly proliferate as a wound healing response. Specifically, resection of up to 20% of the zebrafish ventricle regenerates via the proliferation of already differentiated cardiomyocyte. The cardiomyocytes dedifferentiation is observed through detachment from other cells as well as changes in morphology.
Between 5:00pm and 6:00pm, people in England, Scotland and Wales who have signed up to the scheme are asked to use less electricity, and will be paid by their energy companies for doing so. Salisbury Crown Court in Wiltshire convicts Lawangeen Abdulrahimzai of a murder he committed in Bournemouth, Dorset, in 2022. 25 January The first ever strike by UK employees of Amazon is held. 300 staff at a Coventry warehouse stage a one-day walk out, in a dispute over pay and conditions. Lawangeen Abdulrahimzai is sentenced to life imprisonment. 26 January – Nicola Sturgeon confirms that Isla Bryson, a trans woman recently convicted of raping two women before her transition, has been moved from Cornton Vale women's prison to HMP Edinburgh men's prison, sparking debate about the Gender Recognition Reform (Scotland) Bill. 27 January Nicola Bulley disappears mysteriously whilst walking her dog beside the River Wyre. COVID-19 in the UK: Data released by the Office for National Statistics for the week ending 17 January indicate overall cases have continued to fall. In England, the estimated number of people testing positive for COVID-19 was 906,300 (roughly 1.62% of the population or 1 in 60 people). 28 January Airline Flybe (2022–2023) cancels all flights to and from the UK after going into administration. Charity Super.Mkt, billed as the UK's first multi-charity store and selling items supplied by ten charities, opens at London's Brent Cross Shopping Centre.
A memorial collection of scientific papers contributed by former pupils and colleagues of Robertson, edited by Sir Charles James Martin and Hedley R. Marston, was published in January 1932 as a special issue of The Australian Journal of Experimental Biology and Medical Science. A memorial window, commissioned by his wife — designed and produced by Edith Lungley, a member of the British Society of Master Glass Painters — was presented to the University of Adelaide, and was unveiled in the Mitchell Building at a ceremony on 18 March 1932 by Sir George Murray, the university's Chancellor. The Medical Sciences Club of South Australia sponsored the annual Brailsford Robertson Memorial Lecture in Robertson's memory. Notable lecturers have been: Sir Howard Florey (1944), Edward Slater (1957)[9], Frank G. Young (1960)[10], Derek Denny-Brown (1964)[11], M.F.A. Woodruff (1965)[12], Stephen Boyden (1968)[13], Geoffrey Burnstock (1971), Frank Macfarlane Burnet (1976)[14], and John B. West (1978). In 2001, the Brailsford Robertson Award was jointly created by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Adelaide specifically to encourage collaborative research in areas of health identified as strategic priorities by the CSIRO Food and Nutritional Sciences division and the University of Adelaide. In 2001, the former CSIRO Division of Animal Nutrition Building on the University of Adelaide's campus was re-named the Brailsford Robertson Building.
== Research == Neurostimulation is being studied as a method of treatment. An implanted hypoglossal nerve stimulation system received European CE Mark (Conformité Européenne) approval in March 2012. Also being studied are exercises of the muscles around the mouth and throat through activities such as playing the didgeridoo.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.