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.
Updated 2025-09-20. Numbers and descriptions here follow the published literature rather than marketing material.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
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.
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.
=== Development === Insecticides with systemic activity against sucking pests, which are safe to pollinators, are sought after, particularly in view of the partial bans on neonicotinoids. Revised 2023 guidance by registration authorities describes the bee testing that is required for new insecticides to be approved for commercial use.
The world's longest hot dog had been 60 meters (197 ft) long and rested within a 60.3-meter (198 ft) bun. The hot dog was prepared by Shizuoka Meat Producers for the All-Japan Bread Association, which baked the bun and coordinated the event, including official measurement for the world record. The hot dog and bun were the center of a media event in celebration of the Association's 50th anniversary on August 4, 2006, at the Akasaka Prince Hotel in Tokyo. On May 31, 2012, Guinness World Records certified the world record for the most expensive hot dog at US$145.49. The "California Capitol City Dawg", served at Capitol Dawg in Sacramento, California, features a grilled 460 mm (18 in) all-beef, natural-casing frank from Chicago, served on a fresh-baked herb-and-oil focaccia roll, spread with white truffle butter, then grilled. It is topped with whole-grain mustard from France, garlic and herb mayonnaise, sauteed chopped shallots, organic mixed baby greens, maple syrup-marinated and fruitwood-smoked uncured bacon from New Hampshire, chopped tomato, moose cheese from Sweden, sweetened dried cranberries, basil olive oil and pear-cranberry-coconut balsamic vinaigrette, and ground peppercorn. Proceeds from the sale of each 1.4 kg (3 lb) super dog were donated to the Shriners Hospitals for Children. Hot dogs are a popular food for eating competitions. The record for hot dogs eaten in 10 minutes is 83 by Joey Chestnut at the "Chestnut vs. Kobayashi: Unfinished Beef" event on September 2, 2024. The last person to hold the record before Chestnut was Takeru Kobayashi.
=== Energy use === Early assessments of energy use in grey matter signaling suggested that 95% was attributed to neurons and 5% to astrocytes. However, after discovering that action potentials were more efficient than initially believed, the energy budget was adjusted: 70% for dendrites, 15% for axons, and 7% for astrocytes. Previous accounts assumed that astrocytes captured synaptic K+ solely via Kir4.1 channels. However, it's now understood they also utilize Na+/K+ ATPase. Factoring in this active buffering, astrocytic energy demand increases by >200%. This is supported by 3D neuropil reconstructions indicating similar mitochondrial densities in both cell types, as well as cell-specific transcriptomic and proteomic data, and tricarboxylic acid cycle rates. Therefore "Gram-per-gram, astrocytes turn out to be as expensive as neurons".
== See also == Trade Incense trade route, a large network around the Mediterranean and beyond Land of Frankincense (Frankincense Trail), site in Oman Nabataeans, a trader tribe Literature Desi Sangye Gyatso, author of a Tibetan herbal Historia Plantarum (Theophrastus book) Similar plants and products Agarwood Benzoin (resin) Copal Elemi, resin or tree Myrrh, resin Palo santo (Bursera graveolens), tree Pistacia lentiscus (mastic tree), and Mastic (plant resin)
=== Inhibin === Quantification of inhibin A is part of the prenatal quad screen that can be administered during pregnancy at a gestational age of 16–18 weeks. An elevated inhibin A (along with an increased beta-hCG, decreased AFP, and a decreased estriol) is suggestive of the presence of a fetus with Down syndrome. As a screening test, abnormal quad screen test results need to be followed up with more definitive tests. It also has been used as a marker for ovarian cancer. Inhibin B may be used as a marker of spermatogenesis function and male infertility. The mean serum inhibin B level is significantly higher among fertile men (approximately 140 pg/mL) than in infertile men (approximately 80 pg/mL). In men with azoospermia, a positive test for inhibin B slightly raises the chances for successfully achieving pregnancy through testicular sperm extraction (TESE), although the association is not very substantial, having a sensitivity of 0.65 (95% confidence interval [CI]: 0.56–0.74) and a specificity of 0.83 (CI: 0.64–0.93) for prediction the presence of sperm in the testes in non-obstructive azoospermia.
Sources: en.wikipedia.org
==== Comando Vermelho ==== Comando Vermelho (Red Command), often abbreviated as "CV", is Brazil's oldest active criminal organization, which engages primarily in drug trafficking and arms smuggling, as well as truck hijacking, loan sharking, pimping, racketeering and bank robberies, among other criminal activities. Considered the biggest faction in Greater Rio de Janeiro, it has also spread to the rest of the state, as well as nearby Espírito Santo and into the north/northeastern regions of Brazil. The formation of the organization dates back to the late 1970s (during the military dictatorship), on the Cândido Mendes prison (located on Ilha Grande), this penitentiary complex housed both ideological enemies of the regime (such as opposition politicians, journalists, unionists and intellectuals), as well as armed guerrilla fighters (such as members of MR-8 and ALN) and high-profile criminals, which, after a series of massacres and general mistreatment by the prison guards, formed an "self-protective" alliance. Through the transfer of major gang leaders by the Brazilian government, the organization was able to gain control of other prisons and establish itself on the ground in most of the state of Rio, gaining much influence within the ever-growing favela complexes. Later, during the cocaine boom of the 1980s, the gang's focus shifted from petty crime to that of drug and arms trafficking, which proved to be less dangerous than bank robberies and also allowed for larger profits and control of many city municipalities.
== Biosynthesis == Gramicidin S biosynthetic pathway consists of two-enzyme of nonribosomal peptide synthases (NRPSs), gramicidin S synthetase I (GrsA) and gramicidin S synthetase II (GrsB), to give a product as a cyclic decapeptide. Within the biosynthetic pathway, there are total of five modules that specifically recognize, activate, and condense the amino acids to gramicidin S. Starting module GrsA consists of three domains: Adenylation (A) domain where it incorporates the amino acid and activates it by adenylation using ATP, Thiolation (T) domain or peptidyl carrier protein (PCP) in which the adenylated amino acid gets covalently attached to the 4´-phosphopantetheine group and this gets loaded onto the conserved serine in the T domain, Epimerization (E) domain where it epimerizes L-amino acid to D-amino acid. Starting module GrsA loads D-Phe onto the system. Second enzyme cluster GrsB contains four modules, each containing condensation (C), adenylation (A), and thiolation (T) domains and thioesterase domain (TE) at the end. C domain forms a peptide bond between two amino acids, D-Phe and L-Pro. L-Val, L-Orn, and L-Leu are incorporated sequentially by the next three modules of GrsB. After repeating the whole module synthesis once again, TE domain cyclizes and releases the two peptides and dimerize them together to form the final product.
== Research == There is evidence that paroxetine may be effective in the treatment of compulsive gambling and hot flashes. Benefits of paroxetine prescription for diabetic neuropathy or chronic tension headache are uncertain. Although the evidence is conflicting, paroxetine may be effective for the treatment of dysthymia, a chronic disorder involving depressive symptoms for most days of the year. There is evidence to support that paroxetine selectively binds to and inhibits G protein-coupled receptor kinase 2 (GRK2) in mice with heart failure. Since GRK2 regulates the activity of the beta adrenergic receptor, which becomes desensitized in cases of heart failure, paroxetine (or a paroxetine derivative) could be used as a heart failure treatment in the future. Paroxetine has been identified as a potential disease-modifying osteoarthritis drug.
=== Depression === Amphetamine was used to treat depression starting in the 1930s and has been described as the first antidepressant. In clinical studies in the 1970s and 1980s, psychostimulants, including amphetamine and methylphenidate, were found to transiently improve mood in a majority of people with depression and to increase psychomotor activation in almost all individuals. Some clinical trials that used lisdexamfetamine as an add-on therapy with a selective serotonin reuptake inhibitor (SSRI) or serotonin-norepinephrine reuptake inhibitor (SNRI) for treatment-resistant depression indicated that this is no more effective than the use of an SSRI or SNRI alone. Other studies indicated that psychostimulants potentiated antidepressants, and were under-prescribed for treatment-resistant depression. In those studies, patients showed significant improvement in energy, mood, and psychomotor activity. Clinical guidelines advise caution in the use of stimulants for depression and advise them only as second- or third-line adjunctive agents. In February 2014, Shire announced that two late-stage clinical trials had found that Vyvanse was not an effective treatment for depression, and development for this indication was discontinued. A 2018 meta-analysis of randomized controlled trials of lisdexamfetamine for antidepressant augmentation in people with major depressive disorder—the first to be conducted—found that lisdexamfetamine was not significantly better than placebo in improving Montgomery–Åsberg Depression Rating Scale scores, response rates, or remission rates.
Sources: en.wikipedia.org
=== Reduction === Alloxan may be reduced to dialuric acid, which has a reductone structure, similar to ascorbic acid (Vitamin C). However, unlike ascorbic acid, alloxan and dialuric acid have strong pro-oxidant physiological effects. A dimeric derivative alloxantin can be prepared by partial reduction of alloxan with hydrogen sulfide.
Dual polarisation interferometry is a surface-based technique for measuring the optical properties of molecular layers. When used to characterize protein folding, it measures the conformation by determining the overall size of a monolayer of the protein and its density in real time at sub-Angstrom resolution, although real-time measurement of the kinetics of protein folding are limited to processes that occur slower than ~10 Hz. Similar to circular dichroism, the stimulus for folding can be a denaturant or temperature.
== Pathophysiology == The recognised forms of MODY are all due to ineffective insulin production or release by pancreatic beta cells. Several of the defects are mutations of transcription factor genes. One form is due to mutations of the glucokinase gene. For each form of MODY, multiple specific mutations involving different amino acid substitutions have been discovered. In some cases, there are significant differences in the activity of the mutant gene product that contribute to variations in the clinical features of the diabetes (such as degree of insulin deficiency or age of onset).
Harrison's Principles of Internal Medicine is an American textbook of internal medicine. First published in 1950, it is in its 22nd edition (published in 2025 by McGraw-Hill Professional) and comes in two volumes. Although it is aimed at all members of the medical profession, it is mainly used by internists and junior doctors in this field, as well as medical students. It is widely regarded as one of the most authoritative books on internal medicine and has been described as the "most recognized book in all of medicine." The work is named after Tinsley R. Harrison of Birmingham, Alabama, who served as editor-in-chief of the first five editions and established the format of the work: a strong basis of clinical medicine interwoven with an understanding of pathophysiology.
=== Others === Jessamine Lovelace — the ghost guardian of the London Institute. Also known as Jessamine Gray after her secret marriage to Tessa's brother Nate in The Infernal Devices. Jesse Blackthorn — Tatiana's deceased son and Grace Blackthorn's adoptive brother. His spirit can only be seen by his mother, Grace, and Lucie.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
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.