If you have been reading about Pro-Gly-Pro and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-07-14. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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 |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid form |
| Solubility class | Freely soluble in water | Hydrophilic heptapeptide |
| Dry storage temperature | -20 degrees Celsius or lower | Sealed, desiccated, protected from light |
| Solution storage | 2 to 8 degrees Celsius short term | Avoid repeated freeze-thaw cycles |
| Common identification method | Reversed-phase HPLC with mass spectrometry | Confirms purity and molecular mass |
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
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.
"It is so true that Bolívar has tried to persecute every able-bodied Peruvian without cause, and that when Brigadier General La Fuente was responsible for the last transformation of Trujillo [the Riva-Agüero prison] and that it was titled That Pacifier of the North, [Bolívar] instantly tried to overthrow him. La Fuente made the Peruvian cuirassiers hold on and punish the hussars of Bolívar's guard, who wanted to run over them" He was also accused of being very cruel against the troops of the Royal Army of Peru, where the repression was fierce, with executions of those who did not pay tithes, harassment of women, execution of prisoners without trial, slaughter of cattle, desecration of churches, imprisonment of women and children in Huanta and the burning of the towns of Iquicha, Caruahuran and Huayllas (absent violence on the royalist side). The guerrillas had to take refuge in the hills in the Republic of Iquicha. After independence, the royalist Indians of Huanta had to bear the punishment for supporting the monarchists: it was the payment of a tax of 50,000 pesos that the entire homonymous party had to collect (except the towns of Quinua, Guaychán and Acosvinchos), which demanded Marshal Antonio José de Sucre "for having rebelled against the system of Independence and freedom." In said imposition, coca prices were altered and caused an economic crisis. If the Iquicha Indians rose up against Bolívar's republic, it was neither because they were "deceived" nor because they wanted to perpetuate the most oppressive features of the colonial system. Quite the opposite.
Users must be able to conduct experiments on-demand at any time from any location, all through a computer interface. The cloud laboratory must enable a user to digitally replicate the experience of standing in a traditional laboratory and manually operating instruments. It must allow users to specify all aspects of their experiments remotely without lead time, additional software, or outside experts Users must have on-demand access to all the instruments needed to perform their experiment, rendering a physical laboratory unnecessary. Users must be able to perform sample preparation, as well as storage and handling, from a remote setting. Users must be able to script and connect multiple experiments, and conduct data analysis, using a single standardized computer interface.
The localisation of the vestibular binding site, as the primary SSRI binding site in SERT is, is however controversial since some research has shown that the SSRIs work in competitive manner by binding to the drugs binding site, not to the second binding site.
As of 12 August 2024, 13.53 billion COVID-19 vaccine doses have been administered worldwide, with 70.6 percent of the global population having received at least one dose. While 4.19 million vaccines were then being administered daily, only 22.3 percent of people in low-income countries had received at least a first vaccine by September 2022, according to official reports from national health agencies, which are collated by Our World in Data. During a pandemic on the rapid timeline and scale of COVID-19 cases in 2020, international organizations like the World Health Organization (WHO) and Coalition for Epidemic Preparedness Innovations (CEPI), vaccine developers, governments, and industry evaluated the distribution of the eventual vaccine(s). Individual countries producing a vaccine may be persuaded to favor the highest bidder for manufacturing or provide first-class service to their own country. Experts emphasize that licensed vaccines should be available and affordable for people at the frontlines of healthcare and in most need. In April 2020, it was reported that the UK agreed to work with 20 other countries and global organizations, including France, Germany, and Italy, to find a vaccine and share the results, and that UK citizens would not get preferential access to any new COVID‑19 vaccines developed by taxpayer-funded UK universities. Several companies planned to initially manufacture a vaccine at artificially low prices, then increase prices for profitability later if annual vaccinations are needed and as countries build stock for future needs.
==== Uses ==== As mentioned in the section Pathway systems, there were several uses for the Inca roads. The most obvious way in which the Inca people used the road/trail systems was to transport goods. They did this on foot and sometimes with the help of animals (llamas and alpacas). Not only were goods transported throughout the vast empire, but so were ideas and messages. The Inca needed a system of communication, so they relied on Chasquis, otherwise known as messengers. The Chasquis were chosen among the strongest and fittest young males. They ran several miles per day, only to deliver messages. These messengers resided in cabins called "tambos." These structures were positioned along the roads and built by the Inca people. These buildings provided the Chasquis with a place to rest. These places of rest could also be used to house the Inca army in a situation of rebellion or war.
Sources: en.wikipedia.org
Karin Markides, born 1951, is a Swedish professor in analytical chemistry and president and CEO of Okinawa Institute of Science and Technology from 1 June 2023. She was the president of American University of Armenia from 1 July 2019 to 2 December 2022. She was also the president and CEO of Chalmers University of Technology from 2006 to 2015. From 2004 to 2006 she was vice director general for Vinnova. She is also board member of the Royal Swedish Academy of Engineering Sciences since 1992 and a board member of the Royal Swedish Academy of Sciences since 1999. Markides completed her doctorate degree at Stockholm University 1984 with the thesis Organosiloxanes containing cyano groups for capillary chromatography. Following this she started her research career at Brigham Young University in Utah, USA, first as a postdoc, and later as research assistant and associate director. In May 1990 she returned to Sweden as a professor at Uppsala University. Fourteen years later, in May 2004, she was employed as vice director general of Vinnova, the Swedish innovation agency. Markides has been chairman of the Scientific Council for Sustainable Development under the Swedish government (vetenskapliga rådet för hållbar utveckling) since 2015. The council's mission is to give evidence-based, concrete suggestions for development of financial, ecological, cultural and social sustainability for the government's longterm sustainability vision.
== Applications == Lateral flow assays have a wide array of applications and can test a variety of samples including urine, blood, saliva, sweat, serum, and other fluids. They are currently used by clinical laboratories, hospitals, physicians and veterinary clinics, food analysis labs and environmental testing facilities. Immediacy in obtaining results is normally the key factor in choosing this technique, although simplicity and lack of a need for formal equipment are also important factors. These features allow ICTs to be used a at-home test or in pharmacies. Because of their exceptional quality, rapid test are also used routinely in well-equipped laboratories when the demand for test is low. The broad applications of rapid test can be realized because of their simplicity accompanied by high quality analytical production. The sensitivity and specificity of these techniques tend to be comparable to those of other more complex methods, and on occasion significantly better. Other uses for lateral flow assays are food and environmental safety and veterinary medicine for chemicals such as diseases and toxins. LFTs are also commonly used for disease identification such as ebola, but the most common LFT are the home pregnancy and SARS-CoV-2 tests.
=== Gene inactivation/deletion === Deletion of the IGF-1 receptor gene in mice results in lethality during early embryonic development, and for this reason, IGF-1 insensitivity, unlike the case of growth hormone (GH) insensitivity (Laron syndrome), is not observed in the human population.
The same enzyme then catalyses "coupling" of one modified tyrosine with another, via a free-radical-mediated reaction, and when these iodinated bicyclic molecules are released by hydrolysis of the protein, T3 and T4 are the result. Therefore, each thyroglobulin protein molecule ultimately yields very small amounts of thyroid hormone (experimentally observed to be on the order of 5–6 molecules of either T4 or T3 per original molecule of thyroglobulin). Hydrolysis (cleavage to individual amino acids) of the modified protein by proteases then liberates T3 and T4, as well as the non-coupled tyrosine derivatives MIT and DIT. The hormones T4 and T3 are the biologically active agents central to metabolic regulation.
Sources: en.wikipedia.org
In 1953, a reader letter to the Philadelphia Bulletin reported that Italian-Americans working at the World War I–era shipyard known as Hog Island, where emergency shipping was produced for the war effort, introduced the sandwich by putting various meats, cheeses, and lettuce between two slices of bread. This became known as the "Hog Island" sandwich; shortened to "Hoggies", then the "hoagie". Dictionary.com offers the following origin of the term hoagie - n. American English (originally Philadelphia) word for "hero, large sandwich made from a long, split roll"; originally hoggie (c. 1936), traditionally said to be named for the jazz musician Hoagy Carmichael (1899–1981), but the use of the word predates his celebrity and the original spelling seems to suggest another source (perhaps "hog"). The modern spelling dates from about 1945; it may have been altered by influence of Carmichael's nickname. The Philadelphia Almanac and Citizen's Manual offers a different explanation saying the sandwich was created by early-twentieth-century street vendors called "hokey-pokey men", who sold antipasto salad, meats, cookies, and buns with a cut in them. When Gilbert and Sullivan's operetta H.M.S. Pinafore opened in Philadelphia in 1879, bakeries produced a long loaf called the pinafore. Entrepreneurial "hokey-pokey men" sliced the loaf in half, stuffed it with antipasto salad, and sold the world's first "hoagie". This hypothesis seems unlikely, as "hokey pokey" men were known street vendors of an ice cream product.
While the 1967 riots are seen as a turning point in the city's fortunes, Detroit's decline began in the 1950s, during which the city lost almost a tenth of its population. Powerful historical forces buffeted Detroit's single-industry economy, and Detroit's federally supported comeback strategies did little to help. State and local governments responded to the riot with a dramatic increase in minority hiring, including the State Police hiring blacks for the first time, and Detroit more than doubling the number of black police. The Michigan government used its reviews of contracts issued by the state to secure an increase in nonwhite employment. Between August 1967 and the end of the 1969–1970 fiscal year, minority group employment by the contracted companies increased by 21.1 percent. In the aftermath of the riot, the Greater Detroit Board of Commerce launched a campaign to find jobs for ten thousand "previously unemployable" persons, a preponderant number of whom were black. By October 12, 1967, Detroit firms had reportedly hired about five thousand African-Americans since the beginning of the jobs campaign. According to Sidney Fine, "that figure may be an underestimate." The Michigan Historical Review writes that "Just as the riots following the assassination of Martin Luther King Jr.
=== Macular degeneration === Overexpression of VEGF causes increased permeability in blood vessels in addition to stimulating angiogenesis. In wet macular degeneration, VEGF causes proliferation of capillaries into the retina. Since the increase in angiogenesis also causes edema, blood and other retinal fluids leak into the retina, causing loss of vision. Anti-angiogenic drugs targeting the VEGF pathways are now used successfully to treat this type of macular degeneration
=== Sale to Sidney Feltenstein; Grotech subsidiary === In December 1994, Taubman sold A&W to Sidney Feltenstein, with the aim of pushing the chain's international expansion further, while still maintaining its headquarters in Livonia. At the time, there were 790 restaurants (688 in the United States and 102 abroad), with the bulk of the international locations located in Malaysia, Thailand and Japan, as well as in Mexico and the United Arab Emirates. Earlier in 1994, its hundredth international location opened at a tourist attraction in Bangkok: a crocodile farm. In January 1995, operations were taken over by Grotech Capital Partners, for a sum of $20 million, with Feltenstein as the chain's new CEO. An agreement was signed in 1996 with Walmart to provide restaurants in seven locations. The menu would add items depending on the region, with the rest being its standard fare. That year, its restaurants were renovated to feature an aesthetic referred to by Feltenstein as "contemporary nostalgia". The move mirrored that of Dairy Queen, which had also opened a test location with a similar feel. A&W also operated restaurants in Monterrey, a key city in northern Mexico. In 1997, A&W acquired Carousel Snack Bars, including its 175 units in malls. The agreement made the chain the owner of these units, while continuing to franchise restaurants.
== Literature == Kitagaki H (2021). "Medical Application of Substances Derived from Non-Pathogenic Fungi and -Containing". Journal of Fungi. 7 (4): 4. doi:10.3390/jof7040243. PMC 8063943. PMID 33804991. J. E. Smith (6 December 2012). Aspergillus. Springer US. pp. 46ff. ISBN 978-1-4615-2411-3.
Sources: en.wikipedia.org
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.
Reversed-phase HPLC establishes purity, while mass spectrometry confirms the expected molecular mass. Sequence confirmation may use tandem mass spectrometry or peptide mapping. A certificate of analysis typically reports these results alongside the analytical method applied.
In Russia it is a registered medicine available by prescription. In many other countries it is not approved for human use and is supplied only as a research chemical. Import and possession rules differ by jurisdiction, and buyers are responsible for checking local requirements.
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.