The short version of peptidase fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-03-03 and is reviewed periodically as new material appears.
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 is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
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.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
Casein-based glues are formulated from casein, water, and alkalis (usually a mix of hydrated lime and sodium hydroxide). Milk is skimmed to remove the fat, then the milk is soured so that the casein is precipitated as milk curd. The curd is washed (removing the whey), and then the curd is pressed to squeeze out the water (it may even be dried to a powder). The casein is mixed with alkali (usually both sodium and calcium hydroxide) to make glue. Glues made with different mixes of alkalis have different properties. Preservatives may also be added. They were popular for woodworking, including for aircraft, as late as the de Havilland Albatross airliner in 1939. Casein glue is also used in transformer manufacturing (specifically transformer board) due to its oil permeability. Elmer's Glue-All, Elmer's School Glue and many other Borden adhesives were originally made from casein. While one reason was its non-toxic nature, a primary factor was that it was economical to use. Towards the end of the 20th century, Borden replaced casein in all of its popular adhesives with synthetics like PVA. While largely replaced with synthetic resins, casein-based glues still have a use in certain niche applications, such as laminating fireproof doors and the labeling of bottles. Casein glues thin rapidly with increasing temperature, making it easy to apply thin films quickly to label jars and bottles on a production line.
In its most discriminating form, genetic fingerprinting can uniquely discriminate any one person from the entire population of the world. Minute samples of DNA can be isolated from a crime scene and compared to that from suspects or from a DNA database of earlier evidence or convicts. Simpler versions of these tests are often used to rapidly rule out suspects during a criminal investigation. Evidence from decades-old crimes can be tested, confirming or exonerating the people originally convicted. Forensic DNA typing has been an effective way of identifying or exonerating criminal suspects due to analysis of evidence discovered at a crime scene. The human genome has many repetitive regions that can be found within gene sequences or in non-coding regions of the genome. Specifically, up to 40% of human DNA is repetitive. There are two distinct categories for these repetitive, non-coding regions in the genome. The first category is called variable number tandem repeats (VNTR), which are 10–100 base pairs long, and the second category is called short tandem repeats (STR), and these consist of repeated 2–10 base pair sections. PCR is used to amplify several well-known VNTRs and STRs using primers that flank each of the repetitive regions. The sizes of the fragments obtained from any individual for each of the STRs will indicate which alleles are present. By analyzing several STRs for an individual, a set of alleles for each person will be found that statistically is likely to be unique. Researchers have identified the complete sequence of the human genome.
== Mechanism of action == The mechanism of action of omaveloxolone and its related compounds has been demonstrated to be through a combination of activation of the antioxidative transcription factor Nrf2 and inhibition of the pro-inflammatory transcription factor NF-κB. Nrf2 transcriptionally regulates multiple genes that play both direct and indirect roles in producing antioxidative potential and the production of cellular energy (i.e., adenosine triphosphate or ATP) within the mitochondria. Consequently, unlike exogenously administered antioxidants (e.g., vitamin E or Coenzyme Q10), which provide a specific and finite antioxidative potential, omaveloxolone, through Nrf2, broadly activates intracellular and mitochondrial antioxidative pathways, in addition to pathways that may directly increase mitochondrial biogenesis (such as PGC1α) and bioenergetics.
Sources: en.wikipedia.org
=== Amyloid formation === Although ELPs generally form reversible spherical aggregates due to their proline and glycine content, there is a possibility that, under certain conditions such as exceedingly high temperatures, ELPs will form amyloids, or irreversible aggregates of insoluble protein. It is also believed that changes in the ELP backbone leading to a reduction in the proline and glycine content may lead to ELPs with a greater propensity for the amyloid state. As amyloids are implicated in the progression of Alzheimer's disease as well as in prion-based diseases, such as Creutzfeldt-Jakob disease (CJD), modeling of ELP amyloid formation may be useful from a biomedical standpoint.
Marsupial mulgaras have many resemblances to placental mice. Planigale has many resemblances to the deer mouse. The marsupial Tasmanian devil has many resemblances to the placental hyena or a wolverine. Similar skull morphology, large canines and crushing carnassial molars. Marsupial kangaroos and wallabies have many resemblances to the springhares, the viscachas (rodents which are also related to chinchillas), the maras (a large rodent from the cavy family (Caviidae)), and rabbits and hares (lagomorphs). The marsupial lion, Thylacoleo carnifex, had retractable claws, the same way the placental felines (cats) do today. Microbats, toothed whales and shrews developed sonar-like echolocation systems used for orientation, obstacle avoidance and for locating prey. Modern DNA phylogenies of bats have shown that the traditional suborder of echolocating bats (Microchiroptera) is not a true clade, and instead some echolocating bats are more related to non-echolocating Old World fruit bats than to other echolocating species. The implication is that echolocation in at least two lineages of bats, Megachiroptera and Microchiroptera has evolved independently or been lost in Old World fruit bats. Echolocation in bats and whales also both necessitate high frequency hearing. The protein prestin, which confers high hearing sensitivity in mammals, shows molecular convergence between the two main clades of echolocating bats, and also between bats and dolphins. Other hearing genes also show convergence between echolocating taxa.
22 November – With Storm Bert set to arrive in Scotland the following day, bringing snow and ice, Police Scotland urges motorists not to travel. 23 November – Police Scotland arrest seven people in connection with Bonfire Night disturbances in the Pollokshields area of Glasgow. 24 November – Alex Cole-Hamilton, the leader of the Scottish Liberal Democrats says his party will vote down the Scottish Government's upcoming budget if it contains even a "penny" promoting Scottish independence. Police charge a senior British Army officer over an incident during which he took decommissioned hand grenades through security at Edinburgh Airport on 16 October. 25 November – 50 non-essential workers are evacuated from the Valaris 120 oil rig 150 miles off the coast of Aberdeen following a crash with a vessel. 26 November – Aberdeen Football Club withdraws an application for a temporary alcohol licence. 27 November – The Scottish Government launches a public consultation on potential sped limit changes that could see the speed limit reduced from 60 mph to 50 mph for cars on single carriageways, but increased from 40 mph to 50 mph for HGV vehicles. HGVs could also have speed limits on dual carriageways increased to 60 mph. 28 November – The Scottish Government announces that all pensioner households will receive a Winter Fuel Payment from Winter 2025–26, with those on Pension Credit receiving £200 or £300 dependent on age and the rest receiving £100. The Scottish Government abandons plans to upgrade the A96 between Aberdeen and Inverness to make it a full dual carriageway by 2030.
Relative to SARMs, supraphysiological doses of testosterone (300–600 mg/week intramuscular testosterone enanthate) over similar timeframes, like 20 weeks, have been found to result in lean body mass gains of 5 to 8 kg in healthy young men. In addition to selectivity for muscle and bone over the prostate gland, LGD-4033 has also been stated by Ligand Pharmaceuticals researchers to have reduced strength in the sebaceous glands. Reduced activity in stimulating sebaceous gland formation, to about 30 to 50% of that produced by DHT at doses with similar anabolic potency in rats, has also been reported for certain other SARMs, like the steroidal agents TFM-4AS-1 and MK-0773. In addition, enobosarm and MK-0773 have been reported to limitedly stimulate the sebaceous glands in small short-term clinical studies in women.
Sources: en.wikipedia.org
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.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.