Everything below concerns peptide stability. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-14. Where a claim depends on a specific study, the study is described rather than over-claimed.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
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.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
| Property | Value | Notes |
|---|---|---|
| Common route | Intranasal | Also injected in some animal work |
| Solubility class | Freely soluble in water | Solid form is hygroscopic |
| Typical storage | About -20 degrees Celsius | Keep desiccated and dark |
| Purity method | Reverse-phase HPLC | Reported as area percent |
| Confirmatory method | Mass spectrometry | Verifies expected molecular mass |
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
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.
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.
In 1771, Samuel Engel mentions, in his Traité de la nature, de la culture, et de l'utilité des pommes de terre par un ami des hommes, that half of Europeans live on bread and the other half on potatoes, and also that bread is made by mixing a third or a quarter of potato with cereal flour, which gives a dish "preferred by taste, to bread of pure wheat". He refers to various authors, including François Mustel who wrote Mémoire sur les pommes de terre et sur le pain économique. Mustel invented, before 1766, a kind of inverted jointer plane to grate potatoes, peeled or not, into a fine mush that must be mixed with wheat flour: the proportion of one 1/3 flour to 2/3 potatoes gives an edible bread he says, 50% of each ingredient a good one, and at the rate of 2/3 to 1/3, it is difficult to notice that the bread is not pure wheat; the mixture must be kneaded with ordinary sourdough, but less water is used and less heat is applied, which produces an additional saving; this bread keeps fresher for longer, it remains edible for fifteen days, instead of six for traditional bread. This prolongation of freshness, which is very appreciable, encourages many Ardennes farmers to add to their bread, until the 1980s, some 10% of potatoes, the Gaumais going up to 50%. Research on the use of the tuber for bread making was numerous in France at the end of the 18th century, but this did not lead to the massive perpetuation of this practice.
== In popular media == In the Rick and Morty episode "Get Schwifty", the character "Ice-T", voiced by show creator Dan Harmon, is portrayed as secretly being alien royalty exiled to Earth, whose natural shape is a letter T made of water. Ice-T reacted on Twitter by saying "This happens with cartoonists after lots of drugs…. Fn Crazy!!". Despite this, he would later voice the character Magma-Q, the fictional father of Ice-T, in the season 7 Rick and Morty episode "Rise of the Numbericons". Stand-up comedian John Mulaney dedicates a long segment on his comedy special New in Town to the humorous expositional nature of Ice-T's role on Special Victims Unit, saying that his function on the show is to be perpetually amazed by bad things, despite being in a sex crimes unit.
== Functions == Many proteins catalyze a chemical reaction. Other proteins fulfill structural, transport, or signaling roles. Furthermore, numerous proteins have the ability to aggregate into supramolecular assemblies. For example, a ribosome is made up of 90 proteins and RNA. A number of the currently known moonlighting proteins are evolutionarily derived from highly conserved enzymes, also called ancient enzymes. These enzymes are frequently speculated to have evolved moonlighting functions. Since highly conserved proteins are present in many different organisms, this increases the chance that they would develop secondary moonlighting functions. A high fraction of enzymes involved in glycolysis, an ancient universal metabolic pathway, exhibit moonlighting behavior. Furthermore, it has been suggested that as many as 7 out of 10 proteins in glycolysis and 7 out of 8 enzymes of the tricarboxylic acid cycle exhibit moonlighting behavior. An example of a moonlighting enzyme is pyruvate carboxylase. This enzyme catalyzes the carboxylation of pyruvate into oxaloacetate, thereby replenishing the tricarboxylic acid cycle. Surprisingly, in yeast species such as H. polymorpha and P. pastoris, pyruvate carboxylase is also essential for the proper targeting and assembly of the peroxisomal protein alcohol oxidase (AO). AO, the first enzyme of methanol metabolism, is a homo-octameric flavoenzyme. In wild type cells, this enzyme is present as enzymatically active AO octamers in the peroxisomal matrix.
clinical assessment and monitoring interventions assessments and prevention of harm To streamline management, there are 5 phases of therapy from the time of recognition of the condition to resolution:
Sources: en.wikipedia.org
=== Manganese electrolysis === During the electrowinning of manganese, the addition of selenium dioxide decreases the power necessary to operate the electrolysis cells. China is the largest consumer of selenium dioxide for this purpose. For every tonne of manganese, an average 2 kg selenium oxide is used.
Over 2003–2013 for companies that approved 8–13 drugs, the cost per drug could rise to as high as $5.5 billion, due mainly to international geographic expansion for marketing and ongoing costs for Phase IV trials for continuous safety surveillance. Alternatives to conventional drug development have the objective for universities, governments, and the pharmaceutical industry to collaborate and optimize resources. An example of a collaborative drug development initiative is COVID Moonshot, an international open-science project started in March 2020 with the goal of developing an un-patented oral antiviral drug to treat SARS-CoV-2.
== M == MALDI – Matrix-assisted laser desorption/ionization MBE – Molecular beam epitaxy MEIS – Medium energy ion scattering MFM – Magnetic force microscopy MIT – Magnetic induction tomography MPM – Multiphoton fluorescence microscopy MRFM – Magnetic resonance force microscopy MRI – Magnetic resonance imaging MS – Mass spectrometry MS/MS – Tandem mass spectrometry MSGE – Mechanically stimulated gas emission Mössbauer spectroscopy MTA – Microthermal analysis
== Side effects == The side effects for Levonantradol include ptosis, sedation, and ataxia in non-human primates. In rodents, the symptoms include dysphoria, memory impairment, motor incoordination, reduced concentration, and disorientation. Levonantradol also decreases startle response. In humans, side effects include dry mouth, drowsiness, dizziness, altered perception, mild sedation, and lack of concentration. It can cause an increase in heart rate and decrease in blood pressure. Euphoric symptoms rarely occurred in subjects.
16 August – A university reports the release of 'Quad-SDK' which may be the first open source full-stack software for large agile four-legged robots, compatible with the ROS. 17 August A report by Global Forest Watch, using new data, concludes that the amount of tree cover being burned has nearly doubled in the past 20 years. The Nadir crater, likely the result of a second, smaller asteroid that struck around the same time as the Chicxulub impact, is identified and described by researchers. Geologists warn that the world is "woefully underprepared" for a massive volcanic eruption. They estimate a one-in-six chance of a magnitude seven explosion in the next one hundred years. Researchers report the development of floating artificial leaves for light-driven hydrogen and syngas fuel production. The lightweight, flexible devices are scalable and can float on water similar to lotus leaves.
Sources: en.wikipedia.org
Thin-layer chromatography (TLC) is a chromatography technique that separates components in non-volatile mixtures. It is performed on a TLC plate made up of a non-reactive solid coated with a thin layer of adsorbent material. This is called the stationary phase. The sample is deposited on the plate, which is eluted with a solvent or solvent mixture known as the mobile phase (or eluent). This solvent then moves up the plate via capillary action. As with all chromatography, some compounds are more attracted to the mobile phase, while others are more attracted to the stationary phase. Therefore, different compounds move up the TLC plate at different speeds and become separated. To visualize colourless compounds, the plate is viewed under UV light or is stained. Testing different stationary and mobile phases is often necessary to obtain well-defined and separated spots. TLC is quick, simple, and gives high sensitivity for a relatively low cost. It can monitor reaction progress, identify compounds in a mixture, determine purity, or purify small amounts of compound.
The permissible limits for ionizing radiation intensity are consistently being revised downward. The concept of radiation protection now includes regulations for the handling of non-ionizing radiation. In the Federal Republic of Germany, radiation protection regulations are developed and issued by the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV). The Federal Office for Radiation Protection is involved in the technical work. In Switzerland, the Radiation Protection Division of the Federal Office of Public Health is responsible, and in Austria, the Ministry of Climate Action and Energy.
=== Morphology === "Candidatus Magnetoglobus multicellularis" is an obligately multicellular bacteria without a unicellular stage in its lifecycle. It typically consists of 10–40 bacterial cells in an organised spherical structure surrounding an acellular compartment. The entire organism has a diameter of approximately 3 to 12 micrometres. Individual cells are elongated into a pyramidal shape, with the narrow apex facing the acellular compartment in the centre. The outward-facing surface of each cell houses numerous flagella. The cells are all tightly joined by highly specialised intercellular junctions, similar to those found in eukaryotic multicellular organisms. The exterior of the organism features a cellulose matrix that plays a role in cell adhesion and structural integrity.
AM-1235 metabolism differs only slightly from that of JWH-018. AM-1235 N-dealkylation produces 1-fluoropentane instead of pentane or other simple alkanes in general. It had been speculated that the fluoropentane might function as an alkylating agent or be further metabolized into toxic fluoroacetic acid. This is not true, however, as fluoroalkanes do not act as alkylating agents under normal conditions and odd-length fluoroalkane chains metabolize into substantially less toxic fluoropropanoic acid.
Sources: en.wikipedia.org
Most published work uses intranasal application, either as drops or as a nasal spray. Injection routes appear in a smaller set of animal experiments. Oral use is uncommon in the literature because peptide breakdown and poor absorption limit this route.
Reported human trials are few, brief and originate mainly from one country. They describe effects on anxiety-related measures, but sample sizes are small and reporting is limited. The results are widely regarded as preliminary rather than confirmed.
Reverse-phase liquid chromatography is used to assess purity and separation of related impurities. Mass spectrometry confirms that the observed molecular mass matches the expected peptide. A certificate of analysis from the supplier is the usual document of record.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.