Selank 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 2026-06-25. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
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.
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 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.
==== Nicotinic ACh receptors ==== Nicotinic receptors bind the acetylcholine (ACh) neurotransmitter to produce non-selective cation channel flow that generates excitatory postsynaptic responses. Receptor activity, which can be influenced by nicotine consumption, produces feelings of euphoria, relaxation, and inevitably addiction in high levels.
=== Elevated potassium === Hyperkalemia develops when there is excess production (oral intake, tissue breakdown) or ineffective elimination of potassium. Ineffective elimination can be hormonal (in aldosterone deficiency) or due to causes in the kidney that impair excretion. Increased extracellular potassium levels result in depolarization of the membrane potentials of cells due to the increase in the equilibrium potential of potassium. This depolarization opens some voltage-gated sodium channels, but also increases the inactivation at the same time. Since depolarization due to concentration change is slow, it never generates an action potential by itself; instead, it results in accommodation. Above a certain level of potassium, the depolarization inactivates sodium channels, opens potassium channels, thus the cells become refractory. This leads to the impairment of neuromuscular, cardiac, and gastrointestinal organ systems. Of most concern is the impairment of cardiac conduction, which can cause ventricular fibrillation and/or abnormally slow heart rhythms.
=== Multilateral Surveillance === The OECD conducts multilateral surveillance as part of its economic monitoring and policy co-ordination activities among member countries. This function has developed through regular peer reviews, comparative analysis, and policy assessments carried out within the framework of the Organisation's committees and its Economics Department.
Sources: en.wikipedia.org
=== Truett's Grill === In 1996, the first Truett's Grill was opened in Morrow, Georgia. The second location opened in 2003 in McDonough, Georgia, and a third location opened in 2006 in Griffin, Georgia. Similar to the Chick-fil-A Dwarf Houses, these independently owned restaurants offer traditional, sit-down dining and expanded menu selections in a diner-themed restaurant. In 2017, Chick-fil-A demolished several Dwarf House locations to replace them with Truett's Grill locations.
Independent Order of Sons of Abraham - Founded in 1892 by a group of Jewish men who were already members of the Masons, Sons of Benjamin, and the Order of B'rith Abraham. Membership in 1899 almost exclusively in New York and Brooklyn, numbered about 2,400 divided equally between men and women. Independent Order of Sons of Benjamin - Founded in 1877 in New York by a group of men who were already members of the Brith Abraham. By 1899 it had spread to the "principal cities of the United States and the Dominion of Canada." It authorized the creation of female lodges, of which there were about 20 in 1899. In 1899 there were about 18,000 male members and 2,500 women. In 1918 it had 800 members in 25 lodges, of which 450 were located in New York City with 18 lodges. Its headquarters in 1918 were at 953 Third Avenue. Offered the "usual secret society forms, and privileges". The emblem was a triangle between the letters F and P with an L under it. Offered insurance against death under the Metropolitan Life Insurance Company. Independent Western Star Order - Founded in 1894. The Eastern Division was headquartered at 40 Rivington Street. Had 21,000 members in 1918, with 2000 members in 24 lodges in New York City. Offered accident, death, and burial insurance May or may not be related to an order of the same name operating out of Chicago. Independent Workmens Circle - Founded in 1906 in Boston. Open to working men and women and "those in sympathy with the cause of labor". In 1923 had 77 lodges with 5,726 benefit members. Headquarters 86 Leverett Street, Boston.
Wide nose – To narrow a too-wide nose, the plastic surgeon cuts, contours, and rearranges the craniofacial bones to achieve the desired functional and aesthetic outcome of a narrower, straighter nose. To leave no visible, surgical scars upon the new nose, the surgeon effects the osteotome (bone chisel) incisions to the nasal bones beneath the facial skin. Illustration 1: The surgeon cuts the excessively wide bones of the upper nasal dorsum (violet) with an osteotome (bone chisel), then detaches, corrects, and relocates them inwards, to a position, between the ocular orbits (red), that narrows the width of the nasal dorsum. Illustration 2: The surgeon chisels two cuts (incisions) to the nasal bones, each incision begins at the nasal cavity. The first incision begins at the yellow dot and extends upwards, along the green arrow, until meeting the zig-zag line (red). The second incision begins at the blue dot and extends upwards, along the black arrow, until meeting the zig-zag line (red). Once cut and loosened from the face, the nasal bone pieces are corrected, then pushed inwards and re-set, thus narrowing the nose.
Sources: en.wikipedia.org
=== EC 2.4.99: Transferring Other Glycosyl Groups === EC 2.4.99.1: β-galactoside α-(2,6)-sialyltransferase EC 2.4.99.2: β-D-galactosyl-(1→3)-N-acetyl-β-D-galactosaminide α-2,3-sialyltransferase EC 2.4.99.3: α-N-acetylgalactosaminide α-2,6-sialyltransferase EC 2.4.99.4: β-galactoside α-2,3-sialyltransferase EC 2.4.99.5: galactosyldiacylglycerol α-2,3-sialyltransferase EC 2.4.99.6: N-acetyllactosaminide α-2,3-sialyltransferase EC 2.4.99.7: α-N-acetylneuraminyl-2,3-β-galactosyl-1,3-N-acetylgalactosaminide 6-α-sialyltransferase EC 2.4.99.8: α-N-acetylneuraminate α-2,8-sialyltransferase EC 2.4.99.9: lactosylceramide α-2,3-sialyltransferase EC 2.4.99.10: Now included in EC 2.4.99.6, N-acetyllactosaminide α-2,3-sialyltransferase EC 2.4.99.11: Now included with EC 2.4.99.1,β-galactoside α-(2,6)-sialyltransferase EC 2.4.99.12: lipid IVA 3-deoxy-D-manno-octulosonic acid transferase EC 2.4.99.13: (Kdo)-lipid IVA3-deoxy-D-manno-octulosonic acid transferase EC 2.4.99.14: (Kdo)2-lipid IVA (2-8) 3-deoxy-D-manno-octulosonic acid transferase EC 2.4.99.15: (Kdo)3-lipid IVA (2-4) 3-deoxy-D-manno-octulosonic acid transferase EC 2.4.99.16: starch synthase (maltosyl-transferring) EC 2.4.99.17: S-adenosylmethionine:tRNA ribosyltransferase-isomerase EC 2.4.99.18: dolichyl-diphosphooligosaccharide—protein glycotransferase EC 2.4.99.19: undecaprenyl-diphosphooligosaccharide—protein glycotransferase EC 2.4.99.20: 2′-phospho-ADP-ribosyl cyclase/2′-phospho-cyclic-ADP-ribose transferase EC 2.4.99.21: dolichyl-phosphooligosaccharide-protein glycotransferase EC 2.4.99.22: N-acetylglucosaminide α-(2,6)-sialyltransferase
The experimentally determined restraints can be used as input for the structure calculation process. Researchers, using computer programs such as XPLOR-NIH, CYANA, GeNMR, or RosettaNMR attempt to satisfy as many of the restraints as possible, in addition to general properties of proteins such as bond lengths and angles. The algorithms convert the restraints and the general protein properties into energy terms, and then try to minimize this energy. The process results in an ensemble of structures that, if the data were sufficient to dictate a certain fold, will converge.
Kennedy was sworn in as Louisiana's junior U.S. Senator on January 3, 2017. He had resigned his position as state treasurer earlier that day. In June 2017, Kennedy "grilled" Education Secretary Betsy DeVos in a hearing before the Appropriations subcommittee on Labor, Health and Human Service, Education and Related Agencies. In the exchange, he contrasted the lack of school choice available to younger pupils in many rural areas of the country with the numerous brands of mayonnaise available at grocery stores: "Now I can go down to my overpriced Capitol Hill grocery this afternoon and choose among about six different types of mayonnaise. How come I can't do that for my kid?" Kennedy asked. The remark attracted national attention. DeVos replied that the Trump administration budget proposal would give parents and students more power and opportunity so that American education could again become "the envy of the world". Kennedy served as a volunteer substitute teacher for more than a decade in Louisiana public schools to better understand issues in the education system. He attracted comment for his manner in the Senate. A January 2018 Huffington Post article reported: "Since being elected to the Senate a year ago, Kennedy ... has made a name for himself on Capitol Hill with his wit, humor and penchant for folksy expressions―a notable feat in a place where jargon and arcane procedure tend to reign supreme". Kennedy received widespread media attention after he crossed party lines to oppose the appointment of three of Trump's U.S.
Sources: en.wikipedia.org
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.