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Identity And Structural Background — Reference Sheet

By Editorial Desk · published 2026-07-14 · last reviewed 2026-07-30 · Data

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 2026-07-30. 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.

Background and Molecular Identity

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.

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 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

Proposed Mechanisms and Research Endpoints

Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.

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.

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Background and Peptide Identity

Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.

Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.

Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.

Supporting material

In an α-turn the end residues are separated by four peptide bonds (i → i ± 4). In a β-turn (the most common form), by three bonds (i → i ± 3). In a γ-turn, by two bonds (i → i ± 2). In a δ-turn, by one bond (i → i ± 1), which is sterically unlikely. In a π-turn, by five bonds (i → i ± 5).

The compound known as TCV-116 (candesartan) was studied by Japanese scientists using standard laboratory rats. Animal studies were published showing the effectiveness of the compound in 1992–1993, with a pilot study on humans published in the summer of 1993.

Acitretin, sold under the brand names Neotigason and Soriatane, is a second-generation retinoid. It is taken orally, and is typically used for psoriasis. It was patented in Germany in 1974 and approved for medical use in the United States in 1996. Acitretin is an oral retinoid used in the treatment of severe resistant psoriasis. Because of the potential for problems and severe side effects it is generally used in only very severe cases of psoriasis that have been unresponsive to other treatments. It binds to nuclear receptors that regulates gene transcription. They induce keratinocyte differentiation and reduce epidermal hyperplasia, leading to the slowing of cell reproduction. Acitretin is readily absorbed and widely distributed after oral administration. A therapeutic effect occurs after two to four weeks or longer. Patients who have received the medication are advised against giving blood for at least three years due to the risk of birth defects.

Ned Lagin (born March 17, 1948) is an American artist, photographer, scientist, composer, and keyboardist. Lagin is considered a pioneer in the development and use of minicomputers and personal computers in real-time stage and studio music composition and performance. He is known for his electronic music composition Seastones, for performing with the Grateful Dead, and for his photography and art.

By inhibiting LL-37 expression, doxycycline helps to mitigate these downstream inflammatory cascades, thereby reducing inflammation and the symptoms of inflammatory conditions. Doxycycline is used to treat acne vulgaris and rosacea. However, there is no clear understanding of what contributes more: the bacteriostatic properties of doxycycline, which affect bacteria (such as Propionibacterium acnes) on the surface of sebaceous glands even in lower doses called "submicrobial" or "subantimicrobial", or whether doxycycline's anti-inflammatory effects, which reduce inflammation in acne vulgaris and rosacea, including ocular rosacea, contribute more to its therapeutic effectiveness against these skin conditions. Subantimicrobial-dose doxycycline (SDD) can still have a bacteriostatic effect, especially when taken for extended periods, such as several months in treating acne and rosacea. While the SDD is believed to have anti-inflammatory effects rather than solely antibacterial effects, SDD was proven to work by reducing inflammation associated with acne and rosacea. Still, the exact mechanisms have yet to be fully discovered. One probable mechanism is doxycycline's ability to decrease the amount of reactive oxygen species (ROS). Inflammation in rosacea may be associated with increased production of ROS by inflammatory cells; these ROS contribute toward exacerbating symptoms.

Sources: en.wikipedia.org

Notes from published material

The first selective CCKB receptor antagonists were modified peptide molecules such as CI-988 and the more metabolically stable CI-1015, however these were disadvantaged by only being able to be administered by injection and rapid breakdown inside the body, which led to a short half-life and limited utility. Non-peptide CCKB receptor antagonists such as L-365,260, L-369,293, YF-476, RP-69758, LY-288,513, PD-145,942 and the CCKB receptor inverse agonist L-740,093 have since been developed, and while all of the drugs developed so far have suffered from limited bioavailability or other issues which have hindered their clinical development, research in this area continues. CCKA receptors are also expressed in the brain to some extent, and IQM-95333, an antagonist selective for this population of CCKA receptors, was also found to reduce anxiety in animal models. Conversely, inhibition of CCKB receptors in the gut produces similar inhibition of secretion of gastric acid and pepsinogen enzymes as is seen with inhibition of CCKA receptors, suggesting that while the CCKA and CCKB receptors comprise two structurally distinct families which bind different ligands and are primarily expressed in different tissues, they produce similar effects, and the distinction between their gastrointestinal and anxiolytic actions depends mainly on where they are expressed in the body.

=== Contraindications === Ceftriaxone should not be used in those with an allergy to ceftriaxone or any component of the formulation. Although there is negligible cross-reactivity between penicillins and third-generation cephalosporins, caution should still be used when using ceftriaxone in penicillin-sensitive patients. Caution should be used in people who have had previous severe penicillin allergies. It should not be used in hyperbilirubinemic neonates, particularly those who are premature because ceftriaxone is reported to displace bilirubin from albumin binding sites, potentially causing bilirubin encephalopathy. Concomitant use with intravenous calcium-containing solutions/products in neonates (≤28 days) is contraindicated even if administered through different infusion lines due to rare fatal cases of calcium-ceftriaxone precipitations in neonatal lungs and kidneys.

Davy was not a physician, and he never administered nitrous oxide during a surgical procedure. He was, however, the first to document the analgesic effects of nitrous oxide, as well as its potential benefits in relieving pain during surgery:

In a novel study of cystic fibrosis (CF) gene therapy, three tail-clamp peptide nucleic acids (PNAs) alongside donor DNA molecule were engineered to be delivered by nanoparticles to correct F508 del mutations on the cystic fibrosis transmembrane conductance regulator (CFTR) in human bronchial epithelial cells in vivo and in vitro. The F508 del mutation is the most commonly occurring mutation which leads a person to have CF. The F508 mutation leads to a loss of function of the CFTR, which is a plasma membrane chloride channel that is regulated by a cyclic-adenosine monophosphate(cAMP). In this study, they were able to create the novel treatment approach for CF through the use of nanoparticles to correct the F508 del CFTR mutation both in vitro in human bronchial epithelial (HBE) cells and in vivo in a CF mouse model which resulted in the appearance of CFTR-dependent chloride transport.

Nandrolone was probably among the first anabolic steroids to be used as a doping agent in sports in the 1960s. It has been banned at the Olympics since 1974. There are many known cases of doping in sports with nandrolone esters by professional athletes.

Sources: en.wikipedia.org

Further detail

== Toxicities == Nitrofurazone is suspected to be a human carcinogen and is included in California's list of toxic chemicals as defined by Proposition 65. Studies demonstrate that nitrofurazone induces mammary tumors (fibroadenoma and adenocarcinoma) in rats and ovarian tumors in mice. In addition, animal studies demonstrated an increased incidence in convulsive seizures, ovarian atrophy, testicular degeneration, and degeneration of articular cartilage. Proper personal protective equipment should be utilized when handling nitrofurazone.

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For example, if it is undesirable or not possible to radiolabel the antigen or target molecule of interest, a RIA can be done if two different antibodies that recognize the target are available and the target is large enough (e.g., a protein) to present multiple epitopes to the antibodies. One antibody would be radiolabeled as above while the other would remain unmodified. The RIA would begin with the "cold" unlabeled antibody being allowed to interact and bind to the target molecule in solution. Preferably, this unlabeled antibody is immobilized in some way, such as coupled to an agarose bead, coated to a surface, etc. Next, the "hot" radiolabeled antibody is allowed to interact with the first antibody-target molecule complex. After extensive washing, the direct amount of radioactive antibody bound is measured and the amount of target molecule quantified by comparing it to a reference amount assayed at the same time. This method is similar in principle to the non-radioactive sandwich ELISA method.

=== H. G. Wells === Author H. G. Wells was born in Bromley on 21 September 1866, to Sarah and Joseph Wells; his father was the founder of the Bromley Cricket Club and the proprietor of a shop that sold cricket equipment. Wells spent the first 13 years of his life in Bromley. From 1874 to 1879 he attended Tomas Morley's Bromley Academy, at 74 High Street. There was a 'H. G. Wells Centre' in Masons Hill near the southern end of the High Street which housed the Bromley Labour Club (the building was demolished in 2017). In August 2005, the wall honouring Wells in Market Square was repainted; the current wall painting features a rich green background with the same Wells reference and the evolutionary sequence of Homo sapiens featured in Origin of Species by Charles Darwin, a former resident of nearby Downe Village. Wells wrote about Bromley in an early unsigned article in the Pall Mall Gazette in which he expressed satisfaction that he had been born in an earlier, more rural Bromley. A blue plaque marks Wells' birthplace in Market Square, on the wall of what is now a Primark store. A marble plaque appears above the door of 8 South Street, the location of Mrs Knott's Dame school where "Bertie", as he was called as a child, learned to read and write. H. G. Wells featured Bromley in two of his novels: The War in the Air (which refers to Bromley as Bunhill) and The New Machiavelli (in which Bromley is referred to as Bromstead). However, H. G.

==== Hepatitis ==== In this pattern, hepatocellular necrosis is associated with infiltration of inflammatory cells. There can be three types of drug-induced hepatitis. (A) viral hepatitis is the most common, where histological features are similar to acute viral hepatitis. (B) in focal or non-specific hepatitis, scattered foci of cell necrosis may accompany lymphocytic infiltration. (C) chronic hepatitis is very similar to autoimmune hepatitis clinically, serologically, and histologically.

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 chemically?

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.

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