A practical reference on Enkephalinase: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-05-09 and is reviewed periodically as new material appears.
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.
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
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.
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.
Tendons are subject to many types of injuries. There are various forms of tendinopathies or tendon injuries due to overuse. These types of injuries generally result in inflammation and degeneration or weakening of the tendons, which may eventually lead to tendon rupture. Tendinopathies can be caused by a number of factors relating to the tendon extracellular matrix (ECM), and their classification has been difficult because their symptoms and histopathology often are similar. Types of tendinopathy include:
== Spatial xenon oscillations == Large thermal reactors with low flux coupling between regions may experience spatial power oscillations because of the non-uniform presence of xenon-135. Xenon-induced spatial power oscillations occur as a result of rapid perturbations to power distribution that cause the xenon and iodine distribution to be out of phase with the perturbed power distribution. This results in a shift in xenon and iodine distributions that causes the power distribution to change in an opposite direction from the initial perturbation. The instantaneous production rate of xenon-135 is dependent on the iodine-135 concentration and therefore on the local neutron flux history. On the other hand, the destruction rate of xenon-135 is dependent on the instantaneous local neutron flux. The combination of delayed generation and high neutron-capture cross section produces a diversity of impacts on nuclear reactor operation. The mechanism is described in the following four steps.
=== Keith Jackson === A 1989 Washington Post investigative story accused the administration of setting up an 18-year-old black man from Baltimore in a sting operation to showcase the drug problem close to home. The DEA, using an undercover agent, pushed a black 18-year-old high school student, Keith Jackson, to make a sale of crack outside the White House. (Jackson had already sold cocaine to agents on four other occasions.) In a recorded conversation with the agents, Jackson can be heard saying "Where the [Expletive] is the White House?" The agents set up a buy with Jackson in Lafayette Park, just across the street from the White House. Jackson was arrested and convicted of felony possession of crack cocaine with intent to distribute. He had no prior convictions but was sentenced to 10 years in prison based on the mandatory minimum laws of 1988. After his conviction, Jackson was visibly in tears. U.S. District Judge Stanley Sporkin told Jackson at his sentencing, "Bush used you, in the sense of making a big drug speech. But he's a decent man, a man of great compassion. Maybe he can find a way to reduce at least some of that sentence." Bush, when asked about the story, told the Washington Post, "The man went there and sold drugs in front of the White House, didn't he?... I can't feel sorry for this fellow."
Agnolín, Bogan & Lucero (2026) consider Balaena pampaea, Notiocetus romerianus and N. platensis to be nomina dubia, interpreting the fossil material of N. platensis as remains of an indeterminate baleen whale, and interpreting fossils of B. pampaea and N. romerianus as remains of an indeterminate balaenid. Lambert et al. (2026) report shark feeding traces on bones of cetacean specimens from the Pliocene Kattendijk Formation (Belgium), including evidence of a bluntnose sixgill shark feeding on a right whale Balaenella brachyrhynus and evidence of Carcharodon plicatilis feeding on a member of the genus Casatia. López-Galán, Ferrón & Botella (2026) study ecomorphological variation of extant and extinct filter-feeding cetaceans, pachycormiform fishes and selachians, interpreting members of the three groups as repeatedly converging toward analogous functional designs, but also interpreting their convergent evolution as influenced by lineage-specific constraints.
== Causes == The most common cause of cauliflower ear is blunt trauma to the ear leading to a hematoma which, if left untreated, eventually heals to give the distinct appearance of cauliflower ear. Participating in contact sports and martial arts is a typical source of such trauma. The structure of the ear is supported by a cartilaginous scaffold consisting of the following distinct components: the helix, antihelix, concha, tragus, and antitragus. The skin that covers this cartilage is extremely thin with virtually no subcutaneous fat while also strongly attached to the perichondrium, which is richly vascularized to supply the avascular cartilage. Cauliflower ear can also present in the setting of nontraumatic inflammatory injury of auricular connective tissue such as in relapsing polychondritis (RP), a rare rheumatologic disorder in which recurrent episodes of inflammation result in destruction of cartilage of the ears and nose. Joints, eyes, audiovestibular system, cardiovascular system, and respiratory tract can also be involved.
Sources: en.wikipedia.org
Glucose is an osmotic molecule, and can have profound effects on osmotic pressure in high concentrations possibly leading to cell damage or death if stored in the cell without being modified. Glycogen is a non-osmotic molecule, so it can be used as a solution to storing glucose in the cell without disrupting osmotic pressure.
=== South Korea === A member of Parliament refers to a member of the Parliament of South Korea. A total of 253 MPs are elected using the first-past-the-post system from parliamentary constituencies, 30 MPs are elected by proportional compensation, and 17 MPs are elected by mixed member majoritarian. In the Second Republic of Korea or if the Constitution of South Korea is amended as a parliamentary system with bicameralism, only the members of the House of Commons of South Korea are called members of Parliament, while the members of the Senate of South Korea are called senators. The members of provincial legislatures are called members of the Legislative Assembly or MLA. In some provinces, such individuals are called councillors and members of the provincial parliament. Members of the National Assembly enjoy various privileges, including immunity from arrest and immunity for legislative acts, along with high power, allowances, and extensive institutional support such as offices, official vehicles, and drivers. Each lawmaker may employ up to nine butler, whose salaries are fully funded by the state. On this foundation of privileges, political experience, personal networks, and local power bases accumulate, making it easier for children or relatives to enter politics. Although power is not legally inherited, in practice this creates a system in which political influence is passed down within families, resembling a form of aristocratic succession.
A lymph node contains lymphoid tissue, i.e., a meshwork or fibers called reticulum with white blood cells enmeshed in it. The regions where there are few cells within the meshwork are known as lymph sinus. It is lined by reticular cells, fibroblasts and fixed macrophages.
As muscle cells die, they absorb sodium, water, and calcium; the rhabdomyolysis releases potassium, myoglobin, phosphate, thromboplastin, creatine, and creatine kinase. Crush syndrome can directly come from compartment syndrome, if the injury is left untreated. Symptoms include the 5 Ps: pain, pallor, paresthesias (pins and needles), paralysis, and pulselessness.
Half a Life is a book by American author Darin Strauss. It received the National Book Critics Circle Award for memoir in 2011. The memoir grew out of a 2008 This American Life episode entitled "Life After Death," in which the author addressed the effects of a high school traffic accident.
Sources: en.wikipedia.org
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.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.