amino acid sequence is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-04-30. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
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.
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 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.
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.
Laminins are a family of glycoproteins of the extracellular matrix of all animals. They are major constituents of the basement membrane, namely the basal lamina (the protein network foundation for most cells and organs). Laminins are vital to biological activity, influencing cell differentiation, migration, and adhesion. Laminins are heterotrimeric protein complexes with a high molecular mass (~400 to ~900 kDa) and possess three different chains (α, β, and γ) encoded by five, four, and three paralogous genes in humans, respectively. The laminin molecules are named according to their chain composition, e.g. laminin-511 contains α5, β1, and γ1 chains. Fourteen other chain combinations have been identified in vivo. The trimeric proteins intersect, composing a cruciform structure that is able to bind to other molecules of the extracellular matrix and cell membrane. The three short arms have an affinity for binding to other laminin molecules, conducing sheet formation. The long arm is capable of binding to cells and helps anchor organized tissue cells to the basement membrane. Laminins are integral to the structural scaffolding of almost every tissue of an organism—secreted and incorporated into cell-associated extracellular matrices. These glycoproteins are imperative to the maintenance and vitality of tissue; defective laminins can cause muscles to form improperly, leading to a form of muscular dystrophy, lethal skin blistering disease (junctional epidermolysis bullosa), and/or defects of the kidney filter (nephrotic syndrome).
== Pathophysiology == HHS is usually precipitated by an infection, myocardial infarction, stroke or another acute illness. A relative insulin deficiency leads to a serum glucose that is usually higher than 33 mmol/L (600 mg/dL), and a resulting serum osmolarity that is greater than 320 mOsm. This leads to excessive urination (more specifically an osmotic diuresis), which, in turn, leads to volume depletion and hemoconcentration that causes a further increase in blood glucose level. Ketosis is absent because the presence of some insulin inhibits hormone-sensitive lipase-mediated fat tissue breakdown.
After ten minutes, if a yellow-white precipitate is displayed, it is a positive result. If a clear precipitate is displayed, it is a negative result. If a newborn screening was not performed, the result of the newborn screening is a false negative, or the newborn was not treated after a positive result, the clinical findings can be maple syrup odor twelve hours after birth. Four to five days after birth, other signs can present, such as stereotyped movements like "fencing" and "bicycling" along with worsening encephalopathy including lethargy, irregular apnea, and opisthotonus. Seven to ten days after birth, respiratory failure and coma can happen.
Beginning in the 1st millennium BCE, groups of Amerindians including the Muisca, Zenú, Quimbaya, and Tairona developed the political system of cacicazgos with a pyramidal structure of power headed by caciques. The Muisca inhabited mainly the area of what is now the Departments of Boyacá and Cundinamarca high plateau (Altiplano Cundiboyacense) where they formed the Muisca Confederation. They farmed maize, potato, quinoa, and cotton, and traded gold, emeralds, blankets, ceramic handicrafts, coca and especially rock salt with neighboring nations. The Tairona inhabited northern Colombia in the isolated mountain range of Sierra Nevada de Santa Marta. The Quimbaya inhabited regions of the Cauca River Valley between the Western and Central Ranges of the Colombian Andes. Most of the Amerindians practiced agriculture and the social structure of each Indigenous community was different. Some groups of Indigenous people such as the Caribs lived in a state of permanent war, but others had less bellicose attitudes. During the 1200s, Malayo-Polynesians and Amerindians in Colombia made contact, thereby spreading Indigeous Amerindian genetics from Precolonial Colombia to some Pacific Ocean islands. The coconuts found in Colombia which originally come from the Philippines originate from this Precolombian exchange.
Sources: en.wikipedia.org
A third‑generation Kamiokande detector, Hyper‑Kamiokande, is currently under construction and it will be about 5.2 times more massive than Super-Kamiokande (approximately 8 times larger in fiducial volume), designed to start data taking in 2028. It will achieve sensitivities 3–5 times better than Super-Kamiokande after 10 years of data taking. Other important experiments that will have competitive sensitivities in proton decay searches are JUNO in China (which started data taking in January 2026) and DUNE in the US (designed to start data taking in 2031). These three ambitious projects were originally proposed and funded primarily for neutrino‑oscillation studies, but they will nevertheless be able to probe proton decay with high sensitivity, as summarized in the following table.
Estradiol has been assessed for use by rectal administration in a number of studies. Uses of estradiol by this route have included treatment of menopausal symptoms in postmenopausal women. Rectal administration of estradiol is described as qualitatively and quantitatively similar to vaginal administration of estradiol. The use of estradiol by the rectal route considerably bypasses the liver and hence the first-pass metabolism that occurs with oral estradiol, similarly to other parenteral routes of estradiol such as vaginal and transdermal administration. Irritation of the intestines does not usually occur with rectal estradiol. The use of estradiol by the rectal route is not well-accepted by all individuals, and due to its inconvenience, it has been said that rectal administration of estradiol has gained no practical clinical importance. Lauritzen (1986) reported that 3 hours after a single rectal dose of 1 mg micronized estradiol, estradiol levels increased by 620 pg/mL and estrone levels increased by 120 pg/mL. Subsequently, Lauritzen (1987, 1990) reported that 0.5 mg/day and 1 mg/day rectal estradiol resulted in respective estradiol levels of 363 pg/mL and 515 pg/mL 6 hours following the last dose. These estradiol levels are fairly similar to those achieved by vaginal estradiol. The estradiol-to-estrone ratio of rectal estradiol is about 5:1, which likewise is the same as that of vaginal estradiol.
There are two known physiologically and clinically significant 11-oxygenated androgens, 11-ketotestosterone (11KT) and 11-ketodihydrotestosterone (11KDHT), which both bind and activate the androgen receptor with affinities, potencies, and efficacies that are similar to that of testosterone (T) and DHT, respectively. As for 11β-hydroxytestosterone (11OHT) and 11β-hydroxydihydrotestosterone (11OHDHT), the androgenicity of these steroids is a point of research. Although some studies suggest that though 11β-hydroxytestosterone (11OHT) and 11β-hydroxydihydrotestosterone (11OHDHT) may not have significant androgenic activity as they were once thought to possess, they may still be important precursors to androgenic molecules. The relative importance of the androgens depends on their activity, circulating levels, and stability. The steroids 11β-hydroxyandrostenedione (11OHA4) and 11-ketoandrostenedione (11KA4) have been established as having minimal androgen activity, but remain important molecules in this context since they act as androgen precursors. Still, of all physiologically and clinically significant 11-oxygenated androgens, only 11KDHT (but not 11KT) is biosynthesized via a backdoor pathway. The backdoor pathways to 11-oxygenated androgens can be broadly defined as two Δ4 steroid entry points (17OHP and P4) that can undergo a common sequence of several transformations:
Sources: en.wikipedia.org
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.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
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.