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Identity And Structural Background — Deep Dive

By Editorial Desk · published 2025-09-29 · last reviewed 2025-11-14 · Info

Tuftsin analogue 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 2025-11-14. Where a claim depends on a specific study, the study is described rather than over-claimed.

Identity and Structural Background

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.

Background and Peptide Identity

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.

Selank at a glance

PropertyValueNotes
Chemical classSynthetic heptapeptideTuftsin analogue
SequenceThr-Lys-Pro-Arg-Pro-Gly-ProSingle-letter form: TKPRPGP
Molecular formulaC33H57N11O9Calculated for the free peptide
Molecular weightAbout 751.9 g/molDerived from the sequence
AppearanceWhite to off-white powderTypical lyophilised form

Stability, Handling, and Analytical Control

Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.

Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.

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Storage, Analysis, and Regulatory Status

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.

Further detail

Romanowsky was born in 1861 in Pskov Governorate, Russia. He attended the 6th Saint Petersburg Gymnasium. In 1880, he enrolled at the St. Petersburg University. He enrolled for two courses: natural science (physics and mathematics) and medicine. He concentrated on medicine in 1882 for a preparatory course to the Military Medical Academy. He graduated with honors in 1886. On 30 November 1886, he was appointed as a junior resident of the Ivangorod military hospital. After one month, he was transferred to the Revel local infirmary as an associate doctor. In 1889, he was attached to the Saint Petersburg Nikolaevsky Military hospital. He initially worked at the clinical department, and from May 1890, he was the head of the eye department. He obtained his medical degree in 1891 on the thesis "On the question of parasitology and therapy of malaria." Romanowsky died in 1921 in Kislovodsk in North Caucasus.

=== Pre-release === SFM was developed internally at Valve in 2005 and most of it was based on the code from the in-game demo playback tool found in Source. SFM was used to make Day of Defeat: Source trailers with effects that could not be achieved in real-time. The tool was used extensively for certain promotional materials for the release of Team Fortress 2, particularly the Meet the Team trailers. This version of SFM, which ran using Source's in-game tools framework, was unintentionally leaked during the public beta of Team Fortress 2 in September 2007. By 2010, the entire interface was re-implemented using Qt 4 and given its engine branch for further development. Before SFM was released to the public, Team Fortress 2 carried a simplified version of SFM known as the "Replay Editor", which was limited to capturing the actual events occurring throughout a player's life. It provided no ability to modify actions, repeat segments, or apply special effects beyond those already used in-game. However, arbitrary camera angles were possible, such as tracking the movements of other players in action at the time. The Replay Editor also allowed users to upload completed videos to YouTube. On June 27, 2012, SFM became available on a limited basis through Steam, the same day the final Meet the Team video "Meet the Pyro" was released. The open beta for Windows was released as of July 11, 2012. From 2011 to 2018, Valve operated a competition known as the Saxxy Awards for community-made SFM animations.

=== Alienizers === Space Criminal Alienizers (宇宙犯罪者アリエナイザー, Uchū Hanzaisha Arienaizā) is an umbrella term that S.P.D. gives to aliens that commit various crimes on Earth and other planets. Unlike most monsters in the Super Sentai franchise, many of the Alienizers pilot giant robots called Kaijuki (怪重機, Kaijūki; "Monstrous Heavy Industrial Machines"), which are usually provided by Agent Abrella.

Sources: en.wikipedia.org

Background from the literature

Froud, Kristina E.; Wardhaugh, Tina; Banks, Duncan; Saffrey, M. Jill; Stewart, Michael G. (2010). "Colostrinin™ Alleviates Amyloid-β Induced Toxicity in Rat Primary Hippocampal Cultures" (PDF). Journal of Alzheimer's Disease. 20 (2): 423–426. doi:10.3233/JAD-2010-1382. PMID 20164569.

== Planetary models == In the late 1800s speculations on the possible structure of the atom included planetary models with orbiting charged electrons. These models faced a significant constraint. In 1897, Joseph Larmor showed that an accelerating charge would radiate power according to classical electrodynamics, a result known as the Larmor formula. Since electrons forced to remain in orbit are continuously accelerating, they would be mechanically unstable. Larmor noted that electromagnetic effect of multiple electrons, suitably arranged, would cancel each other. Thus subsequent atomic models based on classical electrodynamics needed to adopt such special multi-electron arrangements. In 1903 Hantaro Nagaoka challenged Thomson's plum pudding model with a "Saturnian" model which featured a massive atomic center with a positive charge of 10,000 times the electron charge, surrounded by electrons in rings analogous to those of Saturn. The model was widely discussed, including a detailed study George Schott which claimed it failed to correctly predict atomic spectra. Nagaoka himself abandoned the proposal in 1908.

==== Saddam Hussein ==== In July 2007, the New Statesman printed selected portions of a 1976 piece by Hitchens which they claimed "took a more admiring view of the Iraqi dictator" than his later strong support for ousting Saddam Hussein. In this Hitchens pointed to Iraq's military strength, oil reserves and young leadership to argue that Iraq was "a force to be reckoned with" and described Saddam Hussein as a leader "who has sprung from being an underground revolutionary gunman to perhaps the first visionary Arab statesman since Nasser." He also argued:

Sources: en.wikipedia.org

Reference notes

=== 3D printing === In 2017, scientists from Chalmers University of Technology in Sweden demonstrated cartilage tissue engineering using 3D bioprinting. They used two different bioinks with nanofibrillated cellulose (NFC) to conduct the tests: NFC with alginate (NFC/A) and hyaluronic acid (NFC/HA). The bioinks were co-printed with irradiated human chondrocytes [8]. The team had success with NFC/A. In September 2021, researchers created cartilage repair implants utilizing a process of three-dimensional weaving to combine artificial materials with stem cells. The bioartificial implants are designed to partly dissolve over time, leaving only natural tissues in the repaired joints. As of October 2021, scientists have seen success in treating dogs but further research is required before the technique could move to clinical trials for humans. Also in September 2021, scientists from the Nakayama Lab at Saga University and Kyoto University in Japan fabricated 3D printed cartilage constructs from stem cells.

CoviVac – COVID vaccine Cytestrol acetate – antiestrogen, cytostatic antineoplastic agent Deltaran (delta sleep-inducing peptide) – alcohol withdrawal treatment Dilept (GZR-123) – antipsychotic, neurotensin analogue Diucifon – leprostatic agent Emoxypine (Mexidol; Mexifin) – actoprotector, antioxidant EpiVacCorona – COVID vaccine Eprobemide (Befol) – antidepressant, reversible inhibitor of monoamine oxidase A Ethacizine (ethacyzine; Ethacizin) – antiarrhythmic agent Fabomotizole (Afobazole) – anxiolytic Feprosidnine (Sydnophen) – amphetamine derivative, psychostimulant Fluacizine (Phtorazisin) – tricyclic antidepressant, phenothiazine Fluorothiazinone (CL-55; Ftortiazinon) – investigational antibiotic Fotretamine (Fotrin) – alkylating antineoplastic agent, immunosuppressant Gamofen (gamophen; amphetamine–GABA) – amphetamine derivative, GABATooltip γ-aminobutyric acid analogue, central agent, central depressant Gidazepam (hydazepam, hidazepam) – atypical benzodiazepine, anxiolytic, TSPOTooltip translocator protein agonist/ligand Gludantan (gludantane) – adamantane, antiparkinsonian agent, antidepressant Glufimet (RGPU-238; dimethyl 3-phenylglutamate) – GABATooltip γ-aminobutyric acid and phenibut analogue Glutaron (RGPU-135; neuroglutamine, neuroglutam; β-phenylglutamate; 3-phenylglutamate) – glutamate analogue, psychostimulant, antidepressant, anxiolytic, neuroprotective Hemantane (hymantane) – adamantane, antiparkinsonian agent Hopantenic acid (homopantothenic acid; N-pantoyl-GABA; Pantogam) – central depressant, GABATooltip γ-aminobutyric acid analogue Ipidacrine (Neiromidin) – acetylcholinesterase inhibitor Latrepirdine (dimebolin; Dimebon) – antihistamine, antiserotonergic, nootropic Mecigestone (pentarane B) – progestin Megestrol caproate (MGC) – progestin Meldonium (Mildronate) – anti-ischemia agent Menthyl isovalerate (validolum; Extravalerianic, Validol, Valofin, Menthoval) – anxiolytic Mesocarb (Sidnocarb, Sydnocarb, Synocarb) – amphetamine derivative, psychostimulant Methylphenatine – amphetamine derivative, psychostimulant Methylphenylpiracetam – racetam, sigma σ1 receptor positive allosteric modulator α-Methyltryptamine (αMT; Indopan) – tryptamine derivative, antidepressant Metralindole (Inkazan) – antidepressant, reversible inhibitor of monoamine oxidase A Moracizine (moricizine; Ethmozine) – antiarrhythmic agent Nooglutyl (Nooglutil; N-5-hydroxynicotinoyl-L-glutamate) – nootropic Orenetide (BP101; Libicore; Desirix; Thr-Lys-Pro-Arg-Pro) – investigational small peptide, sexual enhancer Pabofen (pabophen; amphetamine–PABA) – amphetamine derivative, antihypoxic agent Pentarane A (D'6-pentarane) – progestin Phemerazole (femerazol; 5-phenyl-3-methylpyrazole) – sedative, hypnotic, anticonvulsant, muscle relaxant, mammary stimulant Phenatine (phenatin; Fenatine; amphetamine–niacin; N-nicotinoylamphetamine) – amphetamine derivative, psychostimulant, hypotensive agent Phenazepam – benzodiazepine, anxiolytic, sedative, hypnotic Phenibut (β-phenyl-GABA; Anvifen, Fenibut, Noofen; Citrocard, RGPU-147) – central depressant, anxiolytic, GABATooltip γ-aminobutyric acid analogue, gabapentinoid N-Phenylacetyl-L-prolylglycine ethyl ester (omberacetam; Noopept) – nootropic, racetam, cyclic glycine-proline prodrug Phenylphenamine (phenylamphetamine) – amphetamine derivative Phenylpiracetam (fonturacetam; Phenotropil, Actitropil, Carphedon) – psychostimulant, nootropic, racetam Phenylpiracetam hydrazide (fonturacetam hydrazide) – anticonvulsant, racetam Picamilon (N-nicotinoyl-GABA, pycamilon, and pikamilon) – anxiolytic, GABATooltip γ-aminobutyric acid analogue Pipofezine (Azafen, Azaphen) – tricyclic antidepressant Pirlindole (Lifril, Pyrazidol) – antidepressant, reversible inhibitor of monoamine oxidase A, serotonin–norepinephrine reuptake inhibitor Polymethylsiloxane polyhydrate (PMSPH; methylsilicic acid hydrogel; Enterosgel) – enterosorbent Propylphenamine (propylamphetamine; possibly N-propylamphetamine) – amphetamine derivative Prospidium chloride (prospidine) – cytostatic, anti-inflammatory agent Pyridoxiphen (amphetamine–pyridoxine; pyridoxylamphetamine) – amphetamine derivative, sympatholytic, hypotensive agent Quifenadine (Phencarol, Fencarol) – antihistamine RGPU-95 (p-chlorophenylpiracetam) – antidepressant, anxiolytic, racetam RGPU-207 (cyclic GABA derivative) – GABATooltip γ-aminobutyric acid analogue, mitochondrial modulator, racetam RGPU-260 – GABATooltip γ-aminobutyric acid analogue, cardiac stimulant Riamilovir (Triazavirin) – antiviral RU-1205 – analgesic, kappa opioid receptor agonist Selank – tuftsin analogue, nootropic, anxiolytic Semax – ACTHTooltip adrenocorticotropic hormone fragment analogue, nootropic, neuroprotective, neurorestorative Sodium polydihydroxyphenylene thiosulfonate (Hypoxen) – antihypoxic agent Sputnik Light – COVID vaccine Sputnik V – COVID vaccine Sulfozinum (sulfazin) – pyrogenic and pain-inducing agent used in psychiatry, for instance psychosis Temgicoluril (tetramethylglycoluril; Adaptol, Mebicar, Mebicarum, Mebikar) – anxiolytic Testifenon (testiphenon, testiphenone, chlorphenacyl dihydrotestosterone ester) – androgen/anabolic steroid, cytostatic antineoplastic agent Tetrindole – antidepressant, reversible inhibitor of monoamine oxidase A Thiophenatine (N-thionicotinoylamphetamine) – amphetamine derivative Tipindole – serotonin antagonist and monoamine oxidase inhibitor Tolibut (β-(4-methylphenyl)-GABA)) – anxiolytic, analgesic, neuroprotective, GABATooltip γ-aminobutyric acid and phenibut analogue Traneurocin (cycloprolylglycine; CPG; NA-831) – racetam-like neuroprotective, neurogenic, nootropic, and anxiolytic Trimeperidine – opioid analgesic Umifenovir (Arbidol) – antiviral Vishnevsky liniment – topical wound medication Phenamine (Fenamin), a psychostimulant, is not specifically a Russian drug but is rather the Russian name for amphetamine.

== Main cast and characters == Dawn Olivieri as Jenna Ross, Ian's wife who is next in line for control of the Homestead after Ian is incapacitated but struggles to assert command. She must decide whether and how to be generous the Homestead's resources with outsiders while balancing the needs of the insiders. Charles Esten as Cain Ross, Ian's wealthy brother with a shady past who is invited by Jenna after Ian's injury. He considers Jeff a threat and wants Jenna to run the Homestead with a tighter grip and threatens to take over control if she does not keep Jeff in line. Olivia Sanabia as Claire Ross, Jenna's young adult daughter who develops a romance with Abe. She must help her mother while also making her own moral decisions. Bailey Chase as Jeff Eriksson, the former U.S. Army Special Forces soldier and DEA agent who commands the Homestead's security personnel. His clashes with Jenna and Cain over decisions threaten the stability of the Homestead, and his concern over protecting his family leads him to make his own choice of whether to remain there or join Raven Rock. Kearran Giovanni as Tara Eriksson, Jeff's wife and an Army veteran, who forges a friendship with Jenna which is tested as Jeff challenges Jenna and Cain. Tyler Lofton as Abe Eriksson, Jeff and Tara's son and Clare's love interest. He struggles with becoming a man and is torn between his loyalties to his parents and Clare. Georgie Snow White as Georgie Eriksson, Jeff and Tara's adopted daughter who experiences strange visions and lives with a sense of foreboding.

=== Home environment === Poverty, especially in children less than 2 years old, food insecurity and adverse childhood experiences all increase the risk of childhood obesity. Children's food choices are influenced by family meals. In children and young adults aged 11–21, those who had more meals with their family also had greater intake of vegetables, fruits and dairy. The results of a survey in the UK suggest that children raised by their grandparents are more likely to be obese as adults than those raised by their parents. An American study released in 2011 found the more mothers work the more children are more likely to be overweight or obese.

Sources: en.wikipedia.org

Frequently asked questions

What is the peptide sequence of Selank?

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.

How is it related to tuftsin?

Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.

Why do different sources use different names?

Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.

What type of molecule is Selank?

Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.

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