A practical reference on amino acid sequence: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-10-15 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Primary route studied | Intranasal | Also examined parenterally in animal work |
| Reported plasma half-life | Minutes to tens of minutes | Values vary widely between reports |
| Main model systems | Rodent behavioural and cell assays | Human trials are few and small |
| Principal proposed targets | GABA-A receptor, GABA transaminase | Monoamine and neurotrophic pathways also reported |
| Evidence grade | Preliminary | Limited independent replication |
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.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
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.
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
== Detection == Getting a regular eye exam may play a role in identifying the signs of some systemic diseases. "The eye is composed of many different types of tissue. This unique feature makes the eye susceptible to a wide variety of diseases as well as provides insights into many body systems. Almost any part of the eye can give important clues to the diagnosis of systemic diseases. Signs of a systemic disease may be evident on the outer surface of the eye (eyelids, conjunctiva and cornea), middle of the eye and at the back of the eye (retina)." Since 500 B.C., some researchers have believed that the physical condition of the fingernails and toenails can indicate various systemic diseases. Careful examination of the fingernails and toenails may provide clues to underlying systemic diseases , since some diseases have been found to cause disruptions in the nail growth process. The nail plate is the hard keratin cover of the nail. The nail plate is generated by the nail matrix located just under the cuticle. As the nail grows, the area closest to becoming exposed to the outside world (distal) produces the deeper layers of the nail plate, while the part of the nail matrix deeper inside the finger (proximal) makes the superficial layers. Any disruption in this growth process can lead to an alteration in the shape and texture. For example, pitting looks like depressions in the hard part of the nail. Pitting is to be associated with psoriasis, affecting 10% - 50% of patients with that disorder.
Anaerobic respiration is respiration using electron acceptors other than molecular oxygen (O2) in its electron transport chain. In aerobic organisms, electrons are shuttled to an electron transport chain, and the final electron acceptor is oxygen. Molecular oxygen is an excellent electron acceptor. Anaerobes instead use less-oxidizing (in either thermodynamic or kinetics sense) substances such as nitrate (NO−3), fumarate (C4H2O2−4), sulfate (SO2−4), or elemental sulfur (S), among others. These terminal electron acceptors have smaller reduction potentials than O2. Less energy per oxidized molecule is released. Therefore, anaerobic respiration is less efficient than aerobic.
== President of the Council of Ministers of Togo (2025–present) == In 2024, Togo's parliament approved changes to the constitution which converted the country's presidential system to a parliamentary one, stripping off most of the powers of the presidency and making it a ceremonial role and as well as lowering the presidential term from five years to four with re-election permitted just once. The role of the prime minister was renamed President of the Council of Ministers, with most of the powers previously associated with the president being transferred to the role, thus making the President of the Council of Ministers the most powerful person in the country with the most governing authority. The new form of government was known as the Fifth Republic of Togo. The new system took effect on 3 May 2025, where Gnassingbé was sworn in as President of the Council of Ministers, with Jean-Lucien Savi de Tové, a former opposition figure to Gnassingbé's father, being elected by the entire National Assembly and as well as 37 members of the Senate to succeed Gnassingbé as the country's first ceremonial president. The reforms were criticized by the opposition as an attempt for Gnassingbé to remain in power, given the fact that the president of the Council of Ministers has no term limits. They also said that Gnassingbé transferred to this role in an attempt to keep his family's dominance over the country. In June 2025, shortly after Gnassingbé became president of the Council of Ministers, mass protests were held by youth leaders against Gnassingbé, calling for his resignation.
=== Mechanical bonding effects on chemical reactivity === The mechanical bond can reduce the kinetic reactivity of the products, this is ascribed to the increased steric hindrance. Because of this effect hydrogenation of an alkene on the thread of a rotaxane is significantly slower as compared to the equivalent non interlocked thread. This effect has allowed for the isolation of otherwise reactive intermediates. The ability to alter reactivity without altering covalent structure has led to MIMAs being investigated for a number of technological applications.
Sources: en.wikipedia.org
== Structural studies == As of late 2007, 13 structures have been solved for this class of enzymes, with PDB accession codes PDB: 1AY4, PDB: 1AY5, PDB: 1AY8, PDB: 2AY1, PDB: 2AY2, PDB: 2AY3, PDB: 2AY4, PDB: 2AY5, PDB: 2AY6, PDB: 2AY7, PDB: 2AY8, PDB: 2AY9, and PDB: 3TAT.
The Fugates, a family that lived in the hills of Kentucky in the US, had the hereditary form. They are known as the "Blue Fugates". Martin Fugate and Elizabeth Smith, who had married and settled near Hazard, Kentucky, around 1800, were both carriers of the recessive methemoglobinemia (met-H) gene, as was a nearby clan with whom the Fugates descendants intermarried. As a result, many descendants of the Fugates were born with met-H.
== Critical reception == The mod received positive reception from critics and fans. Metrocop.net praised the game for its clever design and atmosphere. Kotaku praised the game for its shooting, calling it a "remarkable mod with great gunfights." The Daily SPUF criticized the difficulty of the game, saying that the normal difficulty was unbalanced with the limited ammo and health, as well as the weapons doing little damage to the enemies while praising its use of the GoldSrc engine to create the setting and recommended it to players. Alice O'Connor of Rock, Paper, Shotgun praised the game's visuals and atmosphere while criticizing the weapons and their lack of damage. The mod was made a Classic of the Month on the Run Think Shoot Live blog in June 2020, and was the Editor's Choice for Mod DB's Mod of The Year 2017.
Sources: en.wikipedia.org
=== For acute coronary syndrome === The combination of a P2Y12 inhibitor and aspirin, called dual antiplatelet treatment, remains the first-line treatment for acute coronary syndrome. A 2019 randomized trial suggested that prasugrel is superior to ticagrelor.
Plaques on house exteriors inform pedestrians where a well-known personality once lived. Often, these plaques are dedicated to Soviet celebrities little known outside Russia (and similarly, for decorated generals and revolutionaries, little known inside Russia). In addition, Moscow contains many "museum houses" dedicated to famous Russian writers, composers, and artists. Moscow's skyline is rapidly modernizing, with several new towers being constructed. In recent years, the city administration has been widely criticized for the widespread destruction of many historical buildings. As much as a third of historic Moscow has been destroyed during the past few years to make space for luxury apartments and hotels. Other historical buildings—including landmarks such as the 1930 Moskva hotel and the 1913 department store Voyentorg—have been razed and rebuilt, with an inevitable loss in historical value. Critics blame the government for not enforcing conservation laws: during the last 12 years, more than 50 buildings with monument status were torn down, several of these dating back to the 17th century. In addition, some critics wonder if the funds used for reconstructing razed buildings could not be used to renovate decaying structures—such as many works of architect Konstantin Melnikov, as well as the Mayakovskaya metro station. Some organizations, such as the Moscow Architecture Preservation Society and Save Europe's Heritage, are trying to attract international public attention to these problems.
== Animal models == Knockout mice of GPX4 die at embryonic day 8 and conditional inducible deletion in adult mice (neurons) results in degeneration and death in less than a month. Targeted disruption of the mitochondrial GPX4 isoform (mGPX4) caused infertility in male mice and disruption of the nuclear GPX4 isoform (nGPX4) reduced the structural stability of sperm chromatin, yet both knockout mouse models (for mGPX4 and nGPX4) were fully viable. Surprisingly, knockout of GPX4 heterozygously in mice (GPX4+/−) increases their median life span. Knockout studies with GPX1, GPX2, or GPX3 deficient mice showed that cytosolic GPX4 is so far the only glutathione peroxidase that is indispensable for embryonic development and cell survival. As mechanisms to dispose of both hydrogen peroxide and lipid hydroperoxides are essential to life, this indicates that in contrast to the multiple metabolic pathways that can be utilized to dispose of hydrogen peroxide, pathways for the disposal of lipid hydroperoxides are limited. While mammals have only one copy of the GPX4 gene, fish have two copies, GPX4a and GPX4b. The GPX4's appear to play a greater role in the fish GPX system than in mammals. For example, in fish GPX4 activity contributes to a greater extent to total GPX activity, GPX4a is the most highly expressed selenoprotein mRNA (in contrast to mammals where it is GPX1 mRNA) and GPX4a appears to be highly inducible to changes within the cellular environment, such as changes in methylmercury and selenium status.
Sources: en.wikipedia.org
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.
The peptide enters plasma rapidly and is broken down by ordinary proteases into amino acids and shorter fragments. Reported half-lives are short. Whether meaningful amounts of the intact molecule reach the brain is an open question.
Most clinical reports are small, published in Russian and not independently replicated. English-language reviews highlight the absence of large randomised trials. Conclusions about efficacy should be treated as provisional.
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.