This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-07-01 and is reviewed periodically as new material appears.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
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.
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.
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.
The four substrates of this enzyme are eucalyptol, reduced nicotinamide adenine dinucleotide phosphate (NADPH), oxygen, and a proton. Its products are 2-exo-hydroxy-1,8-cineole, oxidised NADP+, and water. It is a cytochrome P450 protein containing heme.
By comparison, smaller scale civil defense programs were instituted in the United States starting in the 1950s, where schools and other public buildings had basements stocked with non-perishable food supplies, canned water, first aid, and dosimeter and Geiger counter radiation-measuring devices. Many of the locations were given "fallout shelter" designation signs. CONELRAD radio information systems were adopted, whereby the commercial radio sector (later supplemented by the National Emergency Alarm Repeaters) would broadcast on two AM radio frequencies in the event of a Civil Defense (CD) emergency. These two frequencies, 640 and 1240 kHz, were marked with small CD triangles on the tuning dial of radios of the period, as can still be seen on 1950s-vintage radios on online auction sites and museums. A few backyard fallout shelters were built by private individuals. Henry Kissinger's view on tactical nuclear war in his controversial 1957 book Nuclear Weapons and Foreign Policy was that any nuclear weapon exploded in air burst mode that was below 500 kilotons in yield and thus averting serious fallout, may be more decisive and less costly in human lives than a protracted conventional war. A list of targets made by the United States was released sometime during December 2015 by the U.S. National Archives and Records Administration. The language used to describe targets is "designated ground zeros".
Dihexa (developmental code PNB-0408; also known as N-hexanoic-Tyr-Ile-(6) aminohexanoic amide) is an oligopeptide drug derived from angiotensin IV that binds with high affinity to hepatocyte growth factor (HGF) and potentiates its activity at its receptor, c-Met. The compound has been found to potently improve cognitive function in animal models of Alzheimer's disease-like mental impairment. In an assay of neurotrophic activity, dihexa was found to be seven orders of magnitude more potent than brain-derived neurotrophic factor. According to a patent, "Short duration safety studies with dihexa have uncovered no apparent toxicity. Of particular note is a lack of neoplastic induction, since c-Met is recognized as an oncogene. This is unsurprising since oncogenesis requires multiple mutations including both oncogene induction and tumor suppressor attenuation."
=== Hydrocyanation === Hydrocyanation is an industrial method for producing nitriles from hydrogen cyanide and alkenes. The process requires homogeneous catalysts. An example of hydrocyanation is the production of adiponitrile, a precursor to nylon-6,6 from 1,3-butadiene:
== Safety and regulation == The European Food Safety Authority (EFSA) and the United States Food and Drug Administration (FDA) have evaluated TBHQ and determined that it is safe to consume at the concentration allowed in foods. The FDA and European Union both set an upper limit of 0.02% (200 mg/kg) of the oil or fat content in foods. It has not been approved in Japan, hence import of food containing TBHQ for selling is not allowed in Japan as of 2007. At very high doses, it has some negative health effects on lab animals, such as producing precursors to stomach tumors and damage to DNA. A number of studies have shown that prolonged exposure to very high doses of TBHQ may be carcinogenic, especially for stomach tumors. Other studies, however, have shown opposite effects, including inhibition against HCA-induced carcinogenesis (by depression of metabolic activation) for TBHQ and other phenolic antioxidants (TBHQ was one of several, and not the most potent) and reduction of nitrosamine-induced carcinogenesis (likely due to phase-II enzyme induction via Nrf2). The EFSA considers TBHQ to be noncarcinogenic. A 1986 review of scientific literature concerning the toxicity of TBHQ determined that a wide margin of safety exists between the levels of intake by humans and the doses that produce adverse effects in animal studies. In addition, TBHQ has been identified by high-throughput screening as having potential immunotoxic effects in 2021. It was previously reported in 2014 that TBHQ enhances allergy response in mice by promoting Th2 cells through Nrf2.
Sources: en.wikipedia.org
== In cancer research == In Cullen's paper "Granzymes in Cancer and Immunity" he describes the process of "immune surveillance [as] the process whereby precancerous and malignant cells are recognized by the immune system as damaged and are consequently targeted for elimination". For a tumor to progress it requires conditions within the body and surrounding area to be growth-promoting. Almost all people have suitable immune cells to fight off tumors in the body. Studies have shown that the immune system even has the ability to prevent precancerous cells from growing and arbitrate the regression of established tumors. The dangerous thing about cancer cells is they have the ability to inhibit the function of the immune system. Although a tumor may be in its beginning stage and very weak, it may be giving off chemicals that inhibit the function of the immune system allowing it to grow and become harmful. Tests have shown that mice without granzymes and perforins are at high risk to have tumors spread throughout their body. Tumors have the ability to escape from immune surveillance by secreting immunosuppressive TGF-β. This inhibits proliferation and activation of T cells. TGF-β production is the most potent mechanism of immune avoidance used by tumors. TGF-β inhibits expression of five different cytotoxic genes including perforin, granzyme A, and granzyme B, which then inhibits T cell-mediated tumor clearance.
The application of carbetocin does not affect a non-pregnant uterus with lower oxytocin receptor expression. Carbetocin also functions to thicken the blood, further preventing post-partum hemorrhage. Carbetocin should not be used to induce or augment labor since it could cause cardiac or respiratory distress to mother or infant.
After founding Shapa, Ariely also co-founded the hedge fund Irrational Capital and its associated Clear Motivation Index. For the company, Ariely developed an index measuring human capital based on factors such as motivation and benefits, and created several ETFs based on human capital factor, including the funds listed as HAPI and HAPS.
== Prognosis == The progression to type 2 diabetes mellitus is not inevitable for those with prediabetes. The progression into diabetes mellitus from prediabetes is approximately 25% over three to five years. This increases to 50% risk of progressing to diabetes over 10 years. Diabetes is a leading cause of morbidity and mortality. Effects of the disease may affect larger blood vessels (e.g., atherosclerosis within the larger arteries of the cardiovascular system) or smaller blood vessels, as seen with damage to the retina of the eye, damage to the kidney, and damage to the nerves. Prediabetes is a risk factor for mortality and there is evidence of cardiovascular disease developing prior to a diagnosis of diabetes.
=== Gut and Brain === Signal peptide (1-20) Glicentin (21–89) Oxyntomodulin (OXY or OXM, 53–89) – A further cleavage of Glicentin Glucagon-like peptide 1 (GLP-1, 92–128) – first seven residues further cleaved Glucagon-like peptide 2 (GLP-2, 146–178)
Sources: en.wikipedia.org
== Degradation == When a serpin inhibits a target protease, it forms a permanent complex, which needs to be disposed of. For extracellular serpins, the final serpin-enzyme complexes are rapidly cleared from circulation. One mechanism by which this occurs in mammals is via the low-density lipoprotein receptor-related protein (LRP), which binds to inhibitory complexes made by antithrombin, PAI-1, and neuroserpin, causing cellular uptake. Similarly, the Drosophila necrotic serpin is degraded in the lysosome after being trafficked into the cell by the Lipophorin Receptor-1 (homologous to the mammalian LDL receptor family).
== Personal life == In 1943 Synge married Ann Davies Stephen (1916–1997). Ann Stephen was the daughter of psychologist Karin Stephen and psychoanalyst Adrian Stephen. Ann's sister Judith (1918–1972) was married to documentary artist and photographer Nigel Henderson.
777 was the owner of low-cost carrier Flair Airlines. In June 2022, the Canadian Transportation Agency ruled that Flair is a Canadian airline and can fly domestically, as 777 owns 25% of the shares and had limited its influence on the board since the beginning of the CTA investigation. On March 11, 2023, Airborne Capital Ltd. seized four of its planes operated by Flair over alleged non-payment. In a press conference, Flair CEO Stephen Jones suggested the seizures were motivated by competitors, and that the airline owed around US$1 million on the leases, and was in the process of making payment when the seizures occurred. The lessor, Airborne alleged that Flair had repeatedly missed payments amounting to several millions of dollars over a period of five months. Flair used other aircraft to continue to operate its schedule. In January 2024, it was reported that the lessors had filed claims at the UK High Court for costs and that there had been outstanding payments of $1.8 million on the four aircraft when notice of default was served. In August 2024, interim CEO Maciej Wilk said that 777's stake in Flair was down to 10% and the company's involvement was mostly as a lender, having no presence in the boardroom.
=== Secondary and tertiary structures === The functional form of single-stranded RNA molecules, just like proteins, frequently requires a specific spatial tertiary structure. The scaffold for this structure is provided by secondary structural elements that are hydrogen bonds within the molecule. This leads to several recognizable "domains" of secondary structure like hairpin loops, bulges, and internal loops. In order to create, i.e., design, RNA for any given secondary structure, two or three bases would not be enough, but four bases are enough. This is likely why nature has "chosen" a four base alphabet: fewer than four would not allow the creation of all structures, while more than four bases are not necessary to do so. Since RNA is charged, metal ions such as Mg2+ are needed to stabilise many secondary and tertiary structures. The naturally occurring enantiomer of RNA is D-RNA composed of D-ribonucleotides. All chirality centers are located in the D-ribose. By the use of L-ribose or rather L-ribonucleotides, L-RNA can be synthesized. L-RNA is much more stable against degradation by RNase. Like other structured biopolymers such as proteins, one can define topology of a folded RNA molecule. This is often done based on arrangement of intra-chain contacts within a folded RNA, termed as circuit topology.
The second level in the physiographic classification schema for the USGS is "province", the same word as Canada uses to divide its political subdivisions, meaning that the terminology used by the two countries do not match below the region level. The lowest level of classification is "section".
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.