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 2026-01-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
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.
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 |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
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.
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.
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.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
A radium industry developed, using radium in creams, beverages, chocolates, toothpastes, and soaps. It took a relatively long time for radium and its decay product radon to be recognized as the cause of the observed effects. Radithor, a radioactive agent consisting of triple-distilled water in which the radium isotopes 226Ra and 228Ra were dissolved so that it had an activity of at least one microcurie, was marketed in the United States. It was not until 1932, when the prominent American athlete Eben Byers, who by his own account had taken about 1,400 vials of Radithor as medicine on the recommendation of his physician, fell seriously ill with cancer, lost many of his teeth, and died shortly thereafter in great agony, that strong doubts were raised about the healing powers of Radithor and radium water.
Two hundred and eighty-six scholars, artists, and scientists received Guggenheim Fellowships in 1970. $2,605,000 was disbursed between the recipients, who were chosen from an applicant pool of 2,313. Of the 81 universities represented, University of California, Berkeley had the most winners on its faculty (23), with Harvard University (17) claiming second and University of California, Los Angeles (10) claiming third.
Fibronectin is a high molecular weight (approximately 500–600 kDa) glycoprotein of the extracellular matrix that binds to membrane-spanning receptor proteins called integrins. Fibronectin also binds to other extracellular matrix proteins such as collagen, fibrin, and heparan sulfate proteoglycans (e.g. syndecans). Fibronectin exists as a protein dimer, consisting of two nearly identical monomers linked by a pair of disulfide bonds. The fibronectin protein is produced from a single gene, but alternative splicing of its pre-mRNA leads to the creation of several isoforms. Two types of fibronectin are present in vertebrates:
=== Liver injury === A rare but serious side effect of venlafaxine is liver injury. It appears to affect both male and female patients with a median age of 44. Cessation of venlafaxine is one of the appropriate measures of management. While the mechanism of venlafaxine-related liver injury remains unclear, findings suggest that it may be related to a CYP2D6 polymorphism.
8969, which declared the third Friday of August a special holiday in Davao City. He expressed disinterest with his new post, describing it as less engaging compared to his time as mayor. He attempted to resign in 1999 after his son Paolo was accused of mauling a hotel guard, but House Speaker Manny Villar and President Joseph Estrada declined his resignation. After embarking on a diplomatic trip to Brazil between 2000 and 2001, Duterte made a brief stopover in the United States, but as he was about to step out of the Los Angeles International Airport, he was held up by law enforcement officers and interrogated about his travel documents. After the stopover, Duterte never again returned to the United States. In 2001, he was elected mayor of Davao for a fourth unconsecutive term, defeating his former ally, incumbent Mayor Benjamin de Guzman; his estranged sister Jocelyn attempted to run against him as well, but was disqualified by the Commission on Elections. He was re-elected in 2004, defeating de Guzman for the second time, and in 2007 with virtually no opposition. In 2003, Duterte formally laid out the scope of Davao City's Chinatown, the first Chinatown in Mindanao, along the newly renamed Magsaysay Street, while establishing the Davao City Chinatown Development Council to oversee the area's development.
Sources: en.wikipedia.org
=== New Granada (Colombia) === Sailing southeast, the sloop entered the Gulf of Batabano, passing Isla de Pinos and navigating the challenging Jardines y Jardinillos archipelago, a region earlier named by Columbus. Humboldt measured latitudes and studied water characteristics, noting the solitude of the area, which was once frequented by fishermen. The journey was slow, with stops for geological and botanical observations. The crew’s cruelty toward wildlife disturbed Humboldt. After several days, the ship entered open water and was driven off course by winds toward the Cayman Islands before resuming its route to the Colombian coast. On March 24, the ship arrived in the Gulf of Santa Marta, enduring rough weather before seeking shelter near the Rio Sint. The travelers landed in a remote area, where locals regarded them with suspicion. Humboldt met a fellow German among palm wine workers, who offered insights about the climate but little else. After collecting botanical specimens, the travelers faced further storms at sea, nearly capsizing before finally finding shelter. Humboldt attempted to make astronomical observations to determine longitude but was prevented by the captain due to difficult terrain. An encounter with escaped enslaved people left Humboldt reflecting on the region’s hardships and the blunted sympathy caused by slavery. Arriving in Cartagena, Humboldt and Bonpland spent six days confirming geographical data and exploring the area. Cartagena, a key Spanish colonial port, faced challenges in defending its harbor.
The fiber angle (the angle the fiber makes with the long axis of the body) plays a critical role in torsion, if the angle is greater than 54°44', during muscle contraction, torsion and elongation will occur. If the fiber angle is less than 54°44', torsion and shortening will occur.
=== Degrowth === Effective accelerationism stands in stark contrast with the degrowth movement, sometimes described by it as "decelerationism" or "decels". The degrowth movement advocates for reducing economic activity and consumption to address ecological and social issues. Effective accelerationism on the contrary embraces technological progress, energy consumption and the dynamics of capitalism, rather than advocating for a reduction in economic activity.
=== Distribution === Strychnine is transported by plasma and red blood cells. Due to slight protein binding, strychnine leaves the bloodstream quickly and distributes to bodily tissues. Approximately 50% of the ingested dose can enter the tissues in 5 minutes. Also within a few minutes of ingestion, strychnine can be detected in the urine. Little difference was noted between oral and intramuscular administration of strychnine in a 4 mg dose. In persons killed by strychnine, the highest concentrations are found in the blood, liver, kidney and stomach wall. The usual fatal dose is 60–100 mg strychnine and is fatal after a period of 1–2 hours, though lethal doses vary depending on the individual.
== Genetics == The number of chondrocyte cells created and their maturation process can be influenced by multiple different genes and proteins. Two proteins, bone morphogenetic protein 4 (BMP-4) and fibroblast growth factor 2 (FGF2) have been seen to influence the amount of differentiation into chondrocytes. Both proteins are known to play a role in embryonic stem cell differentiation into mesodermal cells, through signaling with BMP-4 and as FGF2 acting as a stimulator. From the mesodermal germ layer, cells will continue to differentiate down into many different types of cells. On top of BMP-4 and FGF2 stimulating the mesodermal germ layer, treatment of these proteins has also been shown to amplify the number of cells that differentiate down into chondrogenic and osteogenic cells when cultured in chondrogenic and osteogenic mediums respectively. For chondrogenic cells, the treatment showed increased expression of the transcription factor Sox9, which plays a key role in chondrogenesis, the process of cartilage formation from condensed mesenchyme tissues, which then differentiate into chondrocytes. Endochondral ossification is the process by which most vertebrate axial skeletons form into hardened bones from cartilage. This process begins with a cartilage anlage where chondrocyte cells will congregate and start their maturation process. Once the chondrocytes have fully matured at the desired rate, the cartilage tissue will harden into bone. This process is similar across most vertebrates and is closely regulated due to the large importance of the skeleton in survival.
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Bhattacharjee, S., Mukherjee, S., and Roy, S.* (2021) J Phys Chem B, 125, 5832-5837.https://doi.org/10.1021/acs.jpcb.1c03794 A peptide-based synthetic transcription factor selectively activates transcription in a mammalian cell. Roy, K., Mazumder, A., Ghosh, P., Naiya, G., Ghosh, B., & Roy, S.* (2018) Chem Commun. 54, 1611-1614.https://doi.org/10.1039/C7CC09279B A Peptide-based Synthetic Transcription Factor Selectively Down-regulates the Proto-oncogene CFOS in Tumour Cells and Inhibits Proliferation. Chakraborty, M. and Roy, S.* (2016) Chem Commun, 53, 376-379.https://doi.org/10.1039/C6CC08086C Specific Sequence of a Beta-turn in Human La Protein May Contribute to Species Specificity of Hepatitis C Virus. Kumar, A., Manna, AK., Ray, U., Mullick, R., Basu, G., Das, S., & Roy, S.* (2014) J Virol, 88, 4319-27. https://doi.org/10.1128/jvi.00049-14 A Synthetic Peptide Mimic of l-Cro shows Sequence-Specific Binding in vitro and in vivo. Mazumder, A., Maiti, A., Roy, K., & Roy, S.* (2012) ACS Chem Biol, 7, 1084-94. https://doi.org/10.1021/cb200523n Peptide-protein interactions suggest that acetylation of lysines 381 and 382 of p53 is important for positive coactivator 4/p53 interaction. Debnath, S., Chatterjee, S., Arif, M., Kundu, TK., & Roy, S.* (2011) J Biol Chem, 286, 25076-87.https://doi.org/10.1074/jbc.M110.205328 Differential recognition of phosphorylated transactivation domains of p53 by different p300 domains. Polley, S., Guha, S., Roy, NS., Kar, S., Sakaguch,i K., Chuman, Y., Swaminathan, V., Kundu, T., & Roy, S.* (2008) J Mol Biol, 376, 8-12.
Papers of Gene Adams (museum educator) Papers of Marina Foster (ILEA teacher and activist) Papers of Brenda Francis (ILEA teacher) Papers of Trevor Jaggar (educator and ILEA schools inspector) Papers of Martin Lightfoot (director of Penguin Education and education textbook reformer) Papers of David Medd and Mary Medd (educational architects) Papers of Professor Kate Myers (education academic who undertook research for ILEA) Papers of Cynthia Reynolds (ILEA teacher) Photographic Archive of the Architects and Building Branch, Ministry of Education Records of the ALPAG (All London Parents Action Group) and Parents Initiative (campaigning organisations) Records of the Records of the ILEA Bridging Course (officially known as the ILEA/EEC Transition from School to Work Project) Records of the London Parents' Ballot Campaign (which campaigned to stop the closure of ILEA) The Institute of Education also holds a library of books and publications which was transferred from the ILEA Learning Resources Branch following its closure in 1990.
Studies on gender and health remain limited. In the early 21st century, life expectancy in France was higher for women than men—85.3 years compared to 79.4 in 2018. However, healthy life expectancy was similar, with women at 64.5 years and men at 63.4 in 2018. Since 2004, healthy life expectancy has increased for men but remained stable for women. Historically, in Western societies, male and female health have been conceptualized differently. From Antiquity onward, the male body was viewed as the standard, while the female body was seen as a variation and more prone to illness. Diagnoses and treatment have differed depending on the patient's sex. In 17th- and 18th-century Europe, women were more often diagnosed with nervous disorders. During this period, medical and state interests in reproduction led to increased study of the female body, particularly as a reproductive body, with a focus on the uterus. New professions, such as midwifery and obstetrics, developed in this context. From the late 18th century onward, sexuality began to be medicalized. Behavioral norms were reframed in medical rather than religious terms, with differences in how male and female behavior were judged. For a prolonged period, women's bodies and intellects were considered inferior in medical discourse, contributing to gendered hierarchies. Women's health was often regarded as pathological or dysfunctional by default. Scientific research has also been shaped by gender bias.
=== Organ meats/offal === Lamb's liver, known as lamb's fry in New Zealand and Australia, is eaten in many countries. It is the most common form of offal eaten in the UK, traditionally used in the family favourite and pub grub staple of liver with onions, potentially also with bacon and mashed potatoes. It is a major ingredient, along with the lungs and heart (the pluck), in the traditional Scottish dish of haggis. Lamb testicles or lamb fries are a delicacy in many parts of the world. Lamb kidneys are found in many cuisines across Europe and the Middle East, often split into two halves and grilled (on kebabs in the Middle East), or sautéed in a sauce. They are generally the most highly regarded of all kidneys. Lamb sweetbreads are a delicacy in many cuisines.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
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.