Selank comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-06-03. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
| 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 |
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
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.
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 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.
Like HMB, creatine is an ergogenic aid that appears to improve anaerobic capacity and muscle mass in individuals who perform high-intensity exercise. When supplemented together, studies have suggested that creatine produces a synergistic effect that can augment HMB-induced improvements on aerobic and anaerobic performance, endurance, and lean body mass in exercise programs of sufficient intensity, relative to HMB alone. In 2006, only about 2% of college student athletes in the United States used HMB as a dietary supplement. As of 2017, HMB has found widespread use as an ergogenic supplement among athletes. As of 2018, HMB has not been banned by the National Collegiate Athletic Association, World Anti-Doping Agency, or any other prominent national or international athletic organization.
The Italian government, presided over by Emilio Colombo after the resignation of Mariano Rumor, appealed to the people of Reggio Emilia to end the violence. Otherwise, it promised the use of force. For the first time in the history of the Italian Republic, the government sent in the army and carabinieri. Even far-left parties, including the Communists and the PSIUP, condemned the uprising, decrying it as parochial and non-proletarian, often clashing with their own voter base. On 23 February 1971, after 10 months of rioting, the revolt ceased given a compromise with the regional government. The Prime Minister, meeting with the president of the Calabria Region, Antonio Guarasci (CD), and regional politicians of various parties, assembled the Colombo Package, which sought to involve all parties: Catanzaro would be the regional capital, while Reggio would host the regional council; Cosenza would be the site of Calabria's first university (University of Calabria), while Gioia Tauro would become the fifth national steel hub and a chemical factory would be established in Saline Joniche. The agreement was accepted by the populace, but the steel plant was never built, while the chemical plant, although built, ceased production almost immediately due to Ministry of Health provisions that declared the feedstocks it produced to be carcinogenic. In the 1972 general elections the scales shifted in favor of the right, which won 27% of the vote and became the leading party in Reggio and Ciccio Franco was elected to the Senate.
=== Peru === The travelers gradually descended into the cinchona forests and former Inca territories. In Riobamba, they stayed with Montufar’s brother, where Humboldt accessed rare sixteenth-century manuscripts written in an extinct dialect and later translated into Spanish. These documents described pre-conquest events and the major eruption of Nevado de Altar volcano, which affected nearby towns with ash for seven years. Traveling from Riobamba to Cuenca across the Paramo of Azuay, Humboldt studied the remains of the Inca road, notable for its precise porphyry paving and straightness, comparable to Roman roads, leading to Cuzco. He also visited the ruins of Inca Tapayupangi’s palace and its summer house carved from rock, which offered impressive views and prompted Humboldt to admire Inca public works. Southward, the group had to ford the Rio Guancabamba, a tributary of the Amazon, twenty-seven times. Although not wide, the river’s strong current endangered their mules, which carried important collections. Humboldt described the anxiety of watching their passage. Further along, he observed the local postal system known as “el correo que nada,” where a messenger swam downstream with mail secured in a cotton handkerchief, sometimes using a balsa log to rest and stopping at huts for food and shelter. Humboldt confirmed the reliability of this system, having received mail sent this way in Paris, and noted that groups of people also traveled the river in this manner.
Sources: en.wikipedia.org
The cytoskeleton is found underlying the cell membrane in the cytoplasm and provides a scaffolding for membrane proteins to anchor to, as well as forming organelles that extend from the cell. Indeed, cytoskeletal elements interact extensively and intimately with the cell membrane. Anchoring proteins restricts them to a particular cell surface—for example, the apical surface of epithelial cells that line the vertebrate gut—and limits how far they may diffuse within the bilayer. The cytoskeleton is able to form appendage-like organelles, such as cilia, which are microtubule-based extensions covered by the cell membrane, and filopodia, which are actin-based extensions. These extensions are ensheathed in membrane and project from the surface of the cell in order to sense the external environment and/or make contact with the substrate or other cells. The apical surfaces of epithelial cells are dense with actin-based finger-like projections known as microvilli, which increase cell surface area and thereby increase the absorption rate of nutrients. Localized decoupling of the cytoskeleton and cell membrane results in formation of a bleb.
Technetium-99m (Tc-99m) can be readily detected in the body by medical equipment because it emits 140.5 keV gamma rays (these are about the same wavelength as emitted by conventional X-ray diagnostic equipment), and its half-life for gamma emission is six hours (meaning 94% of it decays to 99Tc in 24 hours). Besides, it emits virtually no beta radiation, thus keeping radiation dosage low. Its decay product, 99Tc, has a relatively long half-life (211,000 years) and emits little radiation. The short physical half-life of 99mTc and its biological half-life of 1 day with its other favourable properties allows scanning procedures to collect data rapidly and keep total patient radiation exposure low. Chemically, technetium-99m is selectively concentrated in the stomach, thyroid, and salivary glands, and excluded from cerebrospinal fluid; combining it with perchlorate abolishes its selectiveness.
The central problem for those requiring external insulin is picking the right dose of insulin and the right timing. Physiological regulation of blood glucose, as in the non-diabetic, would be best. Increased blood glucose levels after a meal is a stimulus for prompt release of insulin from the pancreas. The increased insulin level causes glucose absorption and storage in cells, reduces glycogen to glucose conversion, reducing blood glucose levels, and so reducing insulin release. The result is that the blood glucose level rises somewhat after eating, and within an hour or so, returns to the normal 'fasting' level. Even the best diabetic treatment with synthetic human insulin or even insulin analogs, however administered, falls far short of normal glucose control in the non-diabetic. Complicating matters is that the composition of the food eaten (see glycemic index) affects intestinal absorption rates. Glucose from some foods is absorbed more (or less) rapidly than the same amount of glucose in other foods. In addition, fats and proteins cause delays in absorption of glucose from carbohydrates eaten at the same time. As well, exercise reduces the need for insulin even when all other factors remain the same, since working muscle has some ability to take up glucose without the help of insulin. Because of the complex and interacting factors, it is, in principle, impossible to know for certain how much insulin (and which type) is needed to 'cover' a particular meal to achieve a reasonable blood glucose level within an hour or two after eating.
Metabolic intermediates are compounds produced during the conversion of substrates (starting molecules) into final products in biochemical reactions within cells. Although these intermediates are of relatively minor direct importance to cellular function, they can play important roles in the allosteric regulation of enzymes, glycolysis, the citric acid cycle, and amino acid synthesis. Metabolic pathways consist of a series of enzymatically catalyzed reactions where each step transforms a substrate into a product that serves as the substrate for the next reaction. Metabolic intermediates are compounds that form during these steps, and they are neither the starting substrate nor the final product of the pathway. These intermediates are crucial because they allow for regulation, energy storage, and extraction of chemical energy in a controlled manner.
Sources: en.wikipedia.org
Ultrafiltration is the most hardware demanding option for protein recovery although it serves more as a protein concentration step rather than complete recovery. Chromatographic methods may be used in tandem with ultrafiltration to help increase solute mass and subsequent recovery. Solvent precipitation is not often reported although it produces the highest protein recovery among other methods and preserves the nutritional integrity of the LPC. The extraction and purification methods are largely inter-compatible and may be employed depending on local facilities. Interestingly, the purity of the final LPC was influenced by the protein content in the initial leaf mass rather than the purification method employed. Furthermore, the amino acid composition of the LPC was dependent on the extraction method employed. In laboratory conditions, protein fractions of 96% purity could be produced with a recovery of 56% w/w and an overall yield of 5.5%. Telek on the other hand experimented with numerous tropical plants at a large scale using a combination of pulping and heat coagulation. Yields were around 3% with protein recoveries <50%. Depending on the purity of the recovered protein, they are either called leaf protein extract (<60% w/w), leaf protein concentrate (>60% w/w), or leaf protein isolate (>90% w/w), although publications use these terms interchangeably.
Following the Molotov–Ribbentrop Pact of 1939, in June 1940 Romania accepted the loss of Bessarabia, Northern Bukovina and the Hertsa region in favour of the USSR (as stipulated in the Soviet ultimatum of 28 June 1940). Unaware of the details of the Soviet–German pact, Carol attempted to secure an alliance with Nazi Germany, and appointed Ion Gigurtu as President of the Council of Ministers, who declared that he would pursue a Nazi pro-Axis (Berlin–Rome) policy that was anti-Semitic and fascist-totalitarian in nature. Between 4 July and 4 September 1940, by accepting Hitler's arbitration over Transylvania (after Gigurtu declared on radio that Romania must make territorial sacrifices to justify its Nazi orientation and full adherence to the Berlin–Rome Axis), Romania ceded Northern Transylvania—including the city of Cluj—to Hungary. The vast territories in Transylvania ceded by Ion Gigurtu to Hungary contained important natural resources, including gold mines. Ion Gigurtu also initiated negotiations to cede 8,000 km2 of Southern Dobruja to Bulgaria, these negotiations were interrupted by Antonescu's unconditional acceptance of the territorial cession. In response to the chaotic withdrawal from Bessarabia, the territorial cessions, public discontent, and protests from political leaders, King Carol II suspended the 1938 Constitution of Romania and appointed General Ion Antonescu as Prime Minister. This measure, supported by the Iron Guard, demanded that the king abdicate in favour of his son, Mihai.
Australia has 43 universities, with 37 being public universities. The Group of Eight includes some of the oldest public universities in Australia, including the University of Queensland, University of Sydney, University of Melbourne, University of New South Wales, University of Adelaide, University of Western Australia, Australian National University, and Monash University. The Australian Technology Network of public universities grew from the former Institutes of Technology and include RMIT University, Queensland University of Technology, Curtin University, the University of Technology Sydney, and the University of South Australia. These former technology institutes gained university status in the late 1980s through the early 1990s due to the reforms made by John Dawkins, then Minister for Employment, Education, and Training. Innovative Research Universities represents several public research-intensive institutions, with most members being established in the 1960s and 1970s. The group includes Charles Darwin University, James Cook University, Griffith University, La Trobe University, Flinders University, Murdoch University, and Western Sydney University. The Regional Universities Network includes seven regional Australian public universities, including Central Queensland University, Southern Cross University, Federation University, the University of Southern Queensland, the University of the Sunshine Coast, University of New England (Australia), and Charles Sturt University.
The genes were compared to those of thousands of other species and while blocks of three or more genes co-occurred between squid and octopus, the blocks of genes were not found together in any other animals'. Many of the groupings were in the nervous tissue, suggesting the course they adapted their intelligence.
Theodosius II (r. 408–450) formalised Roman law by appointing five jurists as principal authorities and compiling legislation issued since Constantine's reign into the Codex Theodosianus. This process culminated in the Corpus Juris Civilis under Justinian I (r. 527–565), who commissioned a complete standardisation of imperial decrees since Hadrian's time and resolved conflicting legal opinions of the jurists. The result became the definitive legal authority. This body of law covered civil matters and also public law, including imperial power and administrative organisation. After 534, Justinian issued the Novellae (New Laws) in Greek, which marked a transition from Roman to Byzantine law. Legal historian Bernard Stolte distinguishes Roman law as this because Western Europe inherited law through the Latin texts of the Corpus Juris Civilis only. Zachary Chitwood argues that the Corpus Juris Civilis was largely inaccessible in Latin, particularly in the provinces. Following the 7th-century Arab conquests, people began questioning the development and application of law, leading to stronger ties between law and Christianity. This context influenced Leo III (r. 717–741) to develop the Ekloge ton nomon, which placed an emphasis on humanity. The Ekloge inspired practical legal texts like the Farmers' Law, Seamen's Law, and Soldiers' Law, which Chitwood suggests were used daily in the provinces as companions to the Corpus Juris Civilis.
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.
Reports describe modulation of GABA signalling, changes in monoamine turnover and effects on neurotrophic factor expression. These observations come mainly from animal and cell studies. A single unifying mechanism has not been demonstrated.