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Identity And Structural Background — Background and Details

By Editorial Desk · published 2025-11-12 · last reviewed 2025-12-09 · Info

If you have been reading about tuftsin and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.

Last reviewed on 2025-12-09. Where a claim depends on a specific study, the study is described rather than over-claimed.

Identity and Structural Background

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.

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.

Selank Origin and Chemical Identity

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.

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.

Selank at a glance

PropertyValueNotes
Chemical classSynthetic heptapeptideTuftsin analogue
SequenceThr-Lys-Pro-Arg-Pro-Gly-ProSingle-letter form: TKPRPGP
Molecular formulaC33H57N11O9Calculated for the free peptide
Molecular weightAbout 751.9 g/molDerived from the sequence
AppearanceWhite to off-white powderTypical lyophilised form

Background and Molecular Identity

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.

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.

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Administration, Testing and Availability

Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.

Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.

Proposed Mechanisms and Research Endpoints

Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.

Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.

Mechanism and Evidence Status

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.

Reference notes

Lowrie has played Sherlock Holmes in the radio drama series The Further Adventures of Sherlock Holmes on the program Imagination Theatre since 2001. He also voiced Holmes in the program's related radio series The Classic Adventures of Sherlock Holmes. He and Lawrence Albert, who voices Dr. Watson on the program, are the longest-running audio Holmes and Watson team in American radio history. In 2011, he published a science fiction novel titled Dancing with Eternity. An audiobook version narrated by Lowrie and McLain was released in April 2014. In 2021, Lowrie directed a livestreamed version of the play 'night, Mother starring his wife Ellen McLain and Sheila Houlahan on the online platform Twitch with the story adapted by McLain within the context of the COVID-19 pandemic. The filmed online play is performed through an online face-to-face chat with the screen split between McLain's and Houlahan's screens, occasionally interrupted by cuts to pre-filmed footage relevant to the story. Lowrie has also had small roles in several live-action films, most notable of which being the 2025 critically acclaimed period drama Train Dreams as a foreman overlooking the construction of a railroad for the Spokane International Railway (credited as Mr. Sears).

== Discovery == It was identified in 2014 in mice where the transcript was found in bone marrow, encoded by the mouse Fam132b gene. The homologous gene in humans is FAM132B and the sequence is conserved in other species. The protein is synthesized by erythroblasts and secreted. This sequence had previously been found expressed in mouse skeletal muscle, called myonectin (CTRP15), and linked to lipid homeostasis. Myonectin was shown in 2015 to be identical to erythroferrone, a hormone produced in erythroblasts that is involved in iron metabolism.

Hyperthyroidism is a endocrine disease in which the thyroid gland produces excessive amounts of thyroid hormones. Thyrotoxicosis is a condition that occurs due to elevated levels of thyroid hormones of any cause and therefore includes hyperthyroidism. Some, however, use the terms interchangeably. Signs and symptoms vary between people and may include irritability, muscle weakness, sleeping problems, a fast heartbeat, heat intolerance, diarrhea, enlargement of the thyroid, hand tremor, and weight loss. Symptoms are typically less severe in the elderly and during pregnancy. An uncommon but life-threatening complication is thyroid storm in which an event such as an infection results in worsening symptoms such as confusion and a high temperature; this often results in death. The opposite is hypothyroidism, when the thyroid gland does not make enough thyroid hormone. Graves' disease is the cause of about 50% to 80% of the cases of hyperthyroidism in the United States. Other causes include multinodular goiter, toxic adenoma, inflammation of the thyroid, eating too much iodine, and too much synthetic thyroid hormone. A less common cause is a pituitary adenoma. The diagnosis may be suspected based on signs and symptoms and then confirmed with blood tests. Typically blood tests show a low thyroid stimulating hormone (TSH) and raised T3 or T4. Radioiodine uptake by the thyroid, thyroid scan, and measurement of antithyroid autoantibodies (thyroidal thyrotropin receptor antibodies are positive in Graves' disease) may help determine the cause.

Sources: en.wikipedia.org

Notes from published material

=== Other benefits === Against the background of the overwhelmingly negative effects of smoking on health, some observational studies have suggested that smoking might have specific beneficial effects, including in the field of cardiovascular disease. Interest in this epidemiological phenomenon has also been aroused by COVID-19. Systematic review of reports that suggested smokers respond better to treatment for ischemic stroke provided no support for such claims. Claims of surprising benefits of smoking, based on observational data, have also been made for Parkinson's disease, as well as a variety of other conditions, including basal-cell carcinoma, melanoma, acute mountain sickness, pemphigus, celiac disease, and ulcerative colitis, among others. Tobacco smoke has many bioactive substances, including nicotine, that are capable of exerting a variety of systemic effects. Surprising correlations may also stem from non-biological factors such as residual confounding (that is to say, the methodological difficulties in completely adjusting for every confounding factor that can affect outcomes in observational studies). For example, in his book Probably Overthinking It, the author Allen B. Downey dissects how a misinterpretation of data on low birth weight of babies born to smoking mothers delayed public-health recommendations against smoking during pregnancy by almost a decade.

=== 25 April === According to RIA Novosti, T-14 Armata tanks were used to fire indirectly on Ukrainian positions but were yet to be deployed in "direct assault operations". The tanks were given extra protection and the crews underwent "combat coordination".

The increased demand and improvements in the synthesis methods resulted in the rise of the annual production of hydrogen peroxide from 35,000 tonnes in 1950, to over 100,000 tonnes in 1960, to 300,000 tonnes by 1970; by 1998 it reached 2.7 million tonnes. Early attempts failed to produce neat hydrogen peroxide. Anhydrous hydrogen peroxide was first obtained by vacuum distillation. Determination of the molecular structure of hydrogen peroxide proved to be very difficult. In 1892, the Italian physical chemist Giacomo Carrara (1864–1925) determined its molecular mass by freezing-point depression, which confirmed that its molecular formula is H2O2. H2O=O seemed to be just as possible as the modern structure, and as late as in the middle of the 20th century at least half a dozen hypothetical isomeric variants of two main options seemed to be consistent with the available evidence. In 1934, the English mathematical physicist William Penney and the Scottish physicist Gordon Sutherland proposed a molecular structure for hydrogen peroxide that was very similar to the presently accepted one.

Sources: en.wikipedia.org

Background from the literature

This transformation of obsidian is accelerated by the presence of water. Although newly formed obsidian has a low water content, typically less than 1% water by weight, it becomes progressively hydrated when exposed to groundwater, forming perlite.

=== Initial adoption === Due to the influence tire pressure has on vehicle safety and efficiency, tire-pressure monitoring (TPM) was adopted by the European market as an optional feature for luxury passenger vehicles in the 1980s. The first passenger vehicle to adopt TPM was the Porsche 959 in 1986, using a hollow spoke wheel system developed by PSK. In 1996 Renault used the Michelin PAX system for the Scenic and in 1999 PSA Peugeot Citroën decided to adopt TPM as a standard feature on the Peugeot 607. The following year (2000), Renault launched the Laguna II, the first high volume mid-size passenger vehicle in the world to be equipped with TPM as a standard feature. In the United States, TPM was introduced by General Motors for the 1991 model year for the Corvette in conjunction with Goodyear run-flat tires. The system uses sensors in the wheels and a driver display which can show tire pressure at any wheel, plus warnings for both high and low pressure. It has been standard on Corvettes ever since.

==== Reading ==== A longitudinal analysis from 1976 to 2016 concluded that "compared with previous generations, teens in the 2010s spent more time online and less time with traditional media, such as books, magazines and television. Time on digital media has displaced time once spent enjoying a book or watching TV." Between 2006 and 2016, usage of digital media, including social networking websites, increased among teenagers while the number of teenagers who read books in their spare time dropped. At school, teachers assign much shorter reading assignments than in the past, and they are less likely to require that students read full-length books. But among teenagers who read for pleasure, dystopian fiction, such as The Hunger Games and Divergent, has proven to be popular. In addition, the surge in reading during the 2000s coincided with the release of the Harry Potter and Twilight novels. Millennial and Gen-Z readers mostly prefer print books to electronic ones. They also tend to like comic books, manga, and graphic novels more than text-only versions of the same stories. Many members of Generation Z have joined BookTok, a community on TikTok where people share and discuss the books they read. So influential is this book club among Generation Z that it has boosted reading for pleasure among this cohort. Even members of Generation Z who do not consider themselves readers enjoy visiting public libraries for social events, classes, or a sense of community.

Sources: en.wikipedia.org

Frequently asked questions

What is the peptide sequence of Selank?

The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.

How is it related to tuftsin?

Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.

Why do different sources use different names?

Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.

What is Selank?

Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.

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