This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-13 and is reviewed periodically as new material appears.
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 a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
| 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 |
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
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.
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.
== Commentary on COVID-19 in New Zealand == In May 2020, Turner, speaking as director for the Immunisation Advisory Centre, supported the use of a vaccine in managing the COVID-19 pandemic in New Zealand and highlighted that it was important to avoid issues of equity of access across the world by privileging the wealthier nations. She concurred with other experts that the vaccine was a key component in responding to the virus and cautioned against unrealistic hopes that it would happen quickly in New Zealand because of supply issues and prioritisation of the administration to the most vulnerable, and those at "heightened risk of infections like border workers and health staff". When New Zealand confirmed the purchase of the Pfizer COVID-19 vaccine, Turner said that while the country had access to both clinical and "real world" data, and was well situated to approve it, there was no need to rush the process. She noted that because there was little "severe illness and death from this disease" in New Zealand, the country was in the privileged position of being able to "scrutinise the science, watch how the vaccine rollout goes for other countries." To Turner, the rollout of a vaccine in New Zealand would be planned and sequential, aiming ultimately for widespread community vaccination.
==== Trans fats ==== Trans fats are naturally occurring in meat and dairy products produced from ruminants, and may be found in foods that have undergone processing, including some commercial baked goods, desserts, margarine, frozen pizza, microwave popcorn and coffee creamers, at increased levels. This is the most unhealthy type of fat, and may increase risk for high cholesterol, heart disease and stroke. The 2010 Dietary Guidelines for Americans recommends keeping trans fat intake as low as possible.
=== Coupling with oxidative phosphorylation === According to the chemiosmotic coupling hypothesis, proposed by Nobel Prize in Chemistry winner Peter D. Mitchell, the electron transport chain and oxidative phosphorylation are coupled by a proton gradient across the inner mitochondrial membrane. The efflux of protons from the mitochondrial matrix creates an electrochemical gradient (proton gradient). This gradient is used by the FOF1 ATP-synthase complex to make ATP via oxidative phosphorylation. ATP-synthase is sometimes described as Complex V of the electron transport chain. The FO component acts as a channel that harnesses the proton flow to drive rotation. It is composed of a, b and c subunits. Protons in the inter-membrane space of mitochondria first enter the ATP-synthase complex through an a subunit channel. Then protons bind to the c subunits, which are oriented in a ring (the c-ring), where the number of c subunits determines how many protons are required to make the c-ring and the attached γ-rotor turn one full revolution. There are 8 c subunits in humans, thus 8 protons are required. Protons are released as a result of the rotation of the c-ring, being directed into the mitochondrial matrix along the a subunit channels. This proton reflux drives the mechanical rotation of the c-ring and the γ-axle. The rotation of the γ-rotor causes the sequential alternation of conformational states in the catalytic β-subunits in F1. There are three different conformational states, which are:
Sources: en.wikipedia.org
== Research directions == Research into the mechanism of HD is focused on identifying the functioning of Htt, how mHtt differs or interferes with it, and the brain pathology that the disease produces. Research is conducted using in vitro methods, genetically modified animals, (also called transgenic animal models), and human volunteers. Animal models are critical for understanding the fundamental mechanisms causing the disease, and for supporting the early stages of drug development. The identification of the causative gene has enabled the development of many genetically modified organisms including nematodes (roundworms), Drosophila fruit flies, and genetically modified mammals including mice, rats, sheep, pigs and monkeys that express mutant huntingtin and develop progressive neurodegeneration and HD-like symptoms. Research is being conducted using many approaches to either prevent HD or slow its progression. Disease-modifying strategies can be broadly grouped into three categories: reducing the level of the mutant huntingtin protein (including gene splicing and gene silencing); approaches aimed at improving neuronal survival by reducing the harm caused by the protein to specific cellular pathways and mechanisms (including protein homeostasis and histone deacetylase inhibition); and strategies to replace lost neurons. In addition, novel therapies to improve brain functioning are under development; these seek to produce symptomatic rather than disease-modifying therapies, and include phosphodiesterase inhibitors.
== Epidemiology == A 1994 community-based study indicated that two out of every 100,000 people with a sCSF, while a 2004 emergency room-based study indicated five per 100,000. sCSF leaks generally affect the young and middle aged; the average age for onset is 42.3 years, but onset can range from ages 22 to 61. In an 11-year study, women were found to be twice as likely to be affected as men. Studies have shown that sCSF leaks runs in families. It is suspected that genetic similarity in families includes weakness in the dura mater which leads to a sCSFL. Large scale population-based studies have not yet been conducted. While a majority of sCSF leaks continue to be undiagnosed or misdiagnosed, an actual increase in occurrence is unlikely.
== Chemistry == Tramadol is marketed as a racemic mixture of both R- and S-stereoisomers, because the two isomers complement each other's analgesic activities. The (+)-isomer is predominantly active as an opiate with a higher affinity for the μ-opiate receptor (20 times higher affinity than the (-)-isomer).
18 January The parties to the Paris Peace Talks came to an agreement on the shape of the conference tables and the placement of the representatives who were negotiating an end to the war. After being delayed for nearly six weeks over procedural disagreements raised by South Vietnamese Vice President Nguyễn Cao Kỳ, the parties came to an accord that "The two sides would be 'clearly separated' by two rectangular tables with a round one in the middle" and that the tables would have "no nameplates, no flags and no written minutes of the understanding" on the setup.
Sources: en.wikipedia.org
==== Females ==== CPA is used as an antiandrogen to treat androgen-dependent skin and hair conditions such as acne, seborrhea, hirsutism (excessive hair growth), scalp hair loss, and hidradenitis suppurativa in women. These conditions are worsened by the presence of androgens, and by suppressing androgen levels and blocking their actions, CPA improves the symptoms of these conditions. CPA is used to treat such conditions both at low doses as a birth control pill and on its own at higher doses. A birth control pill containing low-dose CPA in combination with ethinylestradiol to treat acne has been found to result in overall improvement in 75 to 90% of women, with responses approaching 100% improvement. High-dose CPA alone likewise has been found to improve symptoms of acne by 75 to 90% in women. Discontinuation of CPA has been found to result in marked recurrence of symptoms in up to 70% of women. CPA is one of the most commonly used medications in the treatment of hirsutism, hyperandrogenism, and polycystic ovary syndrome in women throughout the world. Higher dosages of CPA are used in combination with an estrogen specifically at doses of 25 to 100 mg/day cyclically in the treatment of hirsutism in women. The efficacy of such dosages of CPA in the treatment of hirsutism in women appear to be similar to that of spironolactone, flutamide, and finasteride.
== Legality == In the United States, a letter from Terrence L. Boos, Ph.D., Chief Drug & Chemical Evaluation Section Diversion Control Division at the DEA shows they consider nor-BNI a Schedule II substance as a derivative of noroxymorphone due to its broad definition in the CSA covering "derivatives". However, no court cases are known to exist for its prosecution and it is possible this could be challenged in court.
22 February – American company Intuitive Machines' Nova-C lander, named Odysseus, becomes the first commercial vehicle to land on the Moon in the IM-1 mission. The lander includes a Lunar Library that contains a version of the English Wikipedia, artworks, selections from the Internet Archive, portions of the Project Gutenberg, and more. It is projected to reside on the Moon in a readable state for billions of years. 23 February Researchers report studies that, for the first time, measured gravity at microscopic levels. Three new moons of the Solar System are discovered, one around Uranus and two around Neptune, bringing their total known satellites to 28 and 16, respectively. 26 February – A small trial suggests prebiotic resistant starch, contained in many foods, can help in weight loss (~2.8 kg in 8 weeks). 28 February A study links ultra-processed foods to 32 negative health impacts, including a higher risk of heart disease, cancer, type 2 diabetes, adverse mental health, and early death. A study reconstructs the genetic event of tail-loss in human ancestors around 25 million years ago.
==== Beverage ==== In 1966, the company bought a 53% controlling stake in Miller Brewing for $36 million from Lorraine Mulberger, the granddaughter of Frederick Miller, who sold the stake for religious reasons. The company sold the Miller stake in 1969 to Philip Morris for $130 million, after first cancelling an agreed-upon sale to PepsiCo for $120 million. This resulted in a lawsuit.
=== February === 1 February A ban on owning an American XL Bully dog comes into force in England and Wales. It is now a criminal offence to own one of the dogs unless the owner has successfully applied for the dog to be exempt. The Bank of England holds interest rates at 5.25%. Climate activist Greta Thunberg appears at Westminster Magistrates' Court, charged with breaching section 14 of the Public Order Act 1986. Her case, and that of four co-defendants, is thrown out the following day. COVID-19 vaccination in the United Kingdom: The first private service for COVID-19 vaccination begins rolling out to pharmacies around the UK, allowing those who are under 65 to receive the latest booster. 2 February Senior Labour MP Darren Jones confirms that the party has ditched its commitment to spend £28bn a year on green investment schemes if it wins the next general election. The killers of 16-year-old transgender girl Brianna Ghey are named as Scarlett Jenkinson and Eddie Ratcliffe, both aged 15 at the time of the murder in February 2023. They are sentenced at Manchester Crown Court to minimum terms of 22 and 20 years, respectively. Water UK, the umbrella trade organisation for the UK's water companies, says that the average annual water bill is expected to increase by 6% in England and Wales from April, an average rise of £27 to £473. 3 February 2024 Northern Ireland Executive formation: The Northern Ireland Assembly meets to elect a new Speaker. Edwin Poots, a former leader of the DUP, is chosen to be the Assembly's 7th Speaker.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.