heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-06-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
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.
Ado Jimada Gana Muhammad OON (born 18 January 1967) is a Nigerian medical doctor and public health administrator who serves as Global Programme Director of the D-8 Health and Social Protection Programme. He previously served as the Executive Director/CEO of the Nigeria's National Primary Health Care Development Agency (NPHCDA), the government agency responsible for developing national primary health care (PHC) policy and supporting states and local government areas (LGAs) to implement them. Muhammad was appointed to that position on 1 November 2011, by the administration of President Goodluck Jonathan. Prior to his appointment, Muhammad served as a special assistant to the permanent secretary, in the State House, Abuja. Muhammad succeeded Muhammad Ali Pate who was appointed as the Minister of State for Health in 2011.
== Distribution == This species has long been known throughout the world as a common pest, so its origins are uncertain, but it may have originated in Sub-Saharan Africa. It moved into Europe long ago, and was likely introduced to North America from there.
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structural protein Any protein which contributes to the mechanical shape and structure of cells, organelles, or tissues (e.g. collagen and actin), as distinguished from proteins which serve some other purpose, such as enzymes. This distinction is not well-defined, however, as many proteins have both structural and non-structural roles.
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Various other experiments have shown that, besides bearing polymerase properties, ribozymes could have developed other kinds of evolutionarily useful catalytic activity such as synthase, ligase, or aminoacylase activities. Ribozymal aminoacylators and ribozymes with the ability to form peptide bonds might have been crucial to inventing translation. An RNA ligase, in turn, could link various components of quasispecies into one chain, beginning the process of a genome integration. An RNA with a synthase or a synthetase activity could be critical for building compartments and providing building blocks for growing RNA and protein chains as well as other types of molecules. Many examples of this kind of ribozyme are currently known, including a peptidyl transferase ribozyme, a ligase, and a nucleotide synthetase. A transaminoacylator described in 2013 has five nucleotides, which is sufficient for a trans-amino acylation reaction and makes it the smallest ribozyme that has been discovered. It supports a peptidyl-RNA synthesis that could be a precursor for the contemporary process of linking amino acids to tRNA molecules. An RNA ligase's catalytic domain, consisting of 93 nucleotides, proved to be sufficient to catalyse a linking reaction between two RNA chains. Similarly, an acyltransferase ribozyme 82 nucleotides long was sufficient to perform an acyltransfer reaction. Altogether, the results concerning the RNA ligase's catalytic domain and the acyltransferase ribozyme are in agreement with the estimated upper limit of 100 nucleotides set by the error threshold problem.
Model editing techniques also exist in computer vision. Finally, some have argued that the opaqueness of AI systems is a significant source of risk and better understanding of how they function could prevent high-consequence failures in the future. "Inner" interpretability research aims to make ML models less opaque. One goal of this research is to identify what the internal neuron activations represent. For example, researchers identified a neuron in the CLIP artificial intelligence system that responds to images of people in Spider-Man costumes, sketches of Spider-Man, and the word 'spider'. It also involves explaining connections between these neurons or 'circuits'. For example, researchers have identified pattern-matching mechanisms in transformer attention that may play a role in how language models learn from their context. "Inner interpretability" has been compared to neuroscience. In both cases, the goal is to understand what is going on in an intricate system, though ML researchers have the benefit of being able to take perfect measurements and perform arbitrary ablations.
It is an optical analytical technique that analyzes the interference pattern of white light reflected from two surfaces: a layer of immobilized protein on the biosensor tip, and an internal reference layer. Any change in the number of molecules bound to the biosensor tip causes a shift in the interference pattern that can be measured in real-time, providing detailed information regarding the kinetics of association and dissociation of the two molecules as well as the affinity constant for the protein interaction (ka, kd and Kd). Due to sensor configuration, the technique is highly amenable to both purified and crude samples as well as high throughput screening experiments. The detection method can also be used to determine the molar concentration of analytes. Protein activity determination by NMR multi-nuclear relaxation measurements, or 2D-FT NMR spectroscopy in solutions, combined with nonlinear regression analysis of NMR relaxation or 2D-FT spectroscopy data sets. Whereas the concept of water activity is widely known and utilized in the applied biosciences, its complement—the protein activity which quantitates protein–protein interactions—is much less familiar to bioscientists as it is more difficult to determine in dilute solutions of proteins; protein activity is also much harder to determine for concentrated protein solutions when protein aggregation, not merely transient protein association, is often the dominant process.
== Pump operation == The pump can operate in manual mode if certain parameters such as basal rates are programmed by the user. In automated mode, the SmartGuard algorithm requires a CGM to operate. Out of the box, the algorithm also requires a 48-hour warm-up period in manual mode to collect insulin usage data. The algorithm is based on historical trends of insulin doses such as total daily dose. Directly before entering automated mode, the algorithm requires a blood glucose reading from a meter to confirm the proper operation of the CGM. The 780G algorithm adapts by updating itself to the individual user every night at midnight. The insulin delivery amount and timing of both automated basal rates and automated boluses are then precisely controlled by the controller. While in SmartGuard mode, the user can bolus for a meal, change the glucose target, and adjust the active insulin time.
=== EC 1.1.2 With a cytochrome as acceptor === EC 1.1.2.1: glycerolphosphate dehydrogenase. As the acceptor is now known, the enzyme has been transferred to EC 1.1.5.3, glycerol-3-phosphate dehydrogenase. EC 1.1.2.2: mannitol dehydrogenase (cytochrome) EC 1.1.2.3: L-lactate dehydrogenase (cytochrome) EC 1.1.2.4: D-lactate dehydrogenase (cytochrome) EC 1.1.2.5: D-lactate dehydrogenase (cytochrome c-553) EC 1.1.2.6: polyvinyl alcohol dehydrogenase (cytochrome) EC 1.1.2.7: methanol dehydrogenase (cytochrome c) EC 1.1.2.8: alcohol dehydrogenase (cytochrome c) EC 1.1.2.9: 1-butanol dehydrogenase (cytochrome c) EC 1.1.2.10: lanthanide-dependent methanol dehydrogenase EC 1.1.2.11: glucoside 3-dehydrogenase (cytochrome c)
Sources: en.wikipedia.org
Their global dissemination is driven in part by horizontal gene transfer on plasmids and has been associated with selection pressure from colistin use, particularly in food-producing animals. Mobile colistin resistance genes also occur in settings without local agricultural colistin use. A 2026 genomic study from New Zealand, where colistin has never been licensed for use in food-producing animals, characterized 71 mcr-positive clinical isolates and compared them with 1,543 mcr-carrying plasmids sampled from 60 countries and regions between 1984 and 2024. The analysis resolved 14 major plasmid lineages associated with different mcr variants and found frequent co-carriage of other antimicrobial-resistance genes, indicating that transmissible plasmid backbones and co-selection by other resistance determinants can contribute to the persistence and dissemination of mcr genes even where direct colistin selection pressure is limited. The emergence of the mcr-9 gene is quite remarkable. Use of colistin to treat Acinetobacter baumannii infections has led to the development of resistant bacterial strains. They have also developed resistance to the antimicrobial compounds LL-37 and lysozyme, produced by the human immune system. This cross-resistance is caused by gain-of-function mutations to the pmrB gene, which controls the expression of lipid A phosphoethanolamine transferases (similar to mcr-1) located on the bacterial chromosome. Similar results have been obtained with mcr-1 positive E.
=== Regier et al. (2005) === In a 2005 study of nuclear genomes Regier et al. suggest that Hexapoda is most closely related to Branchiopoda and Cephalocarida + Remipedia, thereby hexapods are "terrestrial crustaceans", thus supporting the Pancrustacea hypothesis that maxillopods are not monophyletic (in the following cladograms Maxillopoda subclasses are highlighted). In addition, there appeared some evidence against the Ostracoda monophyly: that Ostracoda subclass Podocopa may form a clade with Branchiura.
Uranium-233, bred from thorium-232 by neutron capture with intermediate decays steps omitted. Uranium-235, which occurs in natural uranium and enriched uranium Plutonium-239, bred from uranium-238 by neutron capture with intermediate decays steps omitted. Plutonium-241, bred from plutonium-240 directly by neutron capture. Fissile nuclides do not have a 100% chance of undergoing fission on absorption of a neutron. The chance is dependent on the nuclide as well as neutron energy. For low and medium-energy neutrons, the neutron capture cross sections for fission (σF), the cross section for neutron capture with emission of a gamma ray (σγ), and the percentage of non-fissions are in the table at right. Fertile nuclides in nuclear fuels include:
== 19th century: the emergence of biological disciplines == Up through the 19th century, the scope of biology was largely divided between medicine, which investigated questions of form and function (i.e., physiology), and natural history, which was concerned with the diversity of life and interactions among different forms of life and between life and non-life. By 1900, much of these domains overlapped, while natural history (and its counterpart natural philosophy) had largely given way to more specialized scientific disciplines—cytology, bacteriology, morphology, embryology, geography, and geology.
=== Parasympathetic activation === In response to the arrival of food in the stomach and small intestine, the activity of the parasympathetic nervous system increases and the activity of the sympathetic nervous system decreases. This shift in the balance of autonomic tone towards the parasympathetic system results in a subjective state of low energy and a desire to be at rest, the opposite of the fight-or-flight state induced by high sympathetic tone. The larger the meal, the greater the shift in autonomic tone towards the parasympathetic system, regardless of the composition of the meal.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.