The short version of Pro-Gly-Pro fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
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.
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 |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
== Metabolism == Telithromycin is metabolized mainly in the liver, the main elimination route being the bile, a small portion is also excreted into the urine. About one third is excreted unchanged in bile and urine, the biliary route being favoured. Telithromycin's half-life is approximately ten hours.
=== Ecology === Naegleria fowleri, an excavate, inhabits soil and water. It is sensitive to drying and acidic conditions, and cannot survive in seawater. The amoeba thrives at moderately elevated temperatures, making infections more likely during the summer months. N. fowleri is a facultative thermophile, capable of growing at temperatures up to 46 °C (115 °F). Warm, fresh water with an ample supply of bacteria as food provides a suitable habitat for amoebae. Locations where many amoebic infections have occurred include artificial bodies of water, disturbed natural habitats, areas with soil, and unchlorinated or unfiltered water. N. fowleri appears to flourish during periods of disturbance. The "flagellate-empty" hypothesis suggests that N. fowleri's success may stem from decreased competition when thermosensitive protozoal fauna do not survive temperature changes. In other words, N. fowleri thrives when other predators consuming its food supply are absent. This hypothesis implies that human disturbances, such as thermal pollution, increase the abundance of N. fowleri by eliminating its resource competitors. Amoeboflagellates have a motile, flagellated stage that aids in dispersal, which is advantageous in environments cleared of competing organisms.
Noroxycodone is the major metabolite of the opioid analgesic oxycodone. It is formed from oxycodone in the liver via N-demethylation predominantly by CYP3A4. Noroxycodone binds to and activates the μ-opioid receptor (MOR) similarly to oxycodone, although with one-third of the affinity of oxycodone and 5- to 10-fold lower activational potency. However, although a potent MOR agonist, noroxycodone poorly crosses the blood-brain-barrier into the central nervous system, and for this reason, is only minimally analgesic in comparison.
=== Structure-activity relationship === Hydrocortisone, or 17-hydroxycorticosterone, is under the class of glucocorticoids, which are steroids synthesized in the adrenal cortex of the kidneys. In order to illustrate its glucocorticoid activity, the A ring of hydrocortisone has a keto group in the 3rd carbon and a double bond between the 4th and 5th carbon. For the C ring of the compound, the 11th carbon has a beta hydroxyl substitution, which is also necessary for the drug to demonstrate glucocorticoid effects.
=== Cancer === Abdominal obesity has been associated with an increased risk of several cancers, particularly malignancies of the digestive system. These include colorectal, pancreatic, and esophageal cancers. These associations often remain even after adjustment for overall body mass index, which suggests that abdominal fat distribution is an independent risk factor. In women, abdominal obesity has also been linked to higher rates of breast cancer in both the pre- and post-menopausal periods, beyond the effects of general obesity.
Sources: en.wikipedia.org
The method was developed by botanist Mikhail Tsvet in 1901–1905 in the universities of Kazan and Warsaw. He developed the technique and coined the term chromatography in the first decade of the 20th century, primarily for the separation of plant pigments such as chlorophyll, carotenes, and xanthophylls. Since these components separate in bands of different colors (green, orange, and yellow, respectively) they directly inspired the name of the technique. New types of chromatography developed during the 1930s and 1940s made the technique useful for many separation processes. Chromatography technique developed substantially as a result of the work of Archer John Porter Martin and Richard Laurence Millington Synge during the 1940s and 1950s, for which they won the 1952 Nobel Prize in Chemistry. They established the principles and basic techniques of partition chromatography, and their work encouraged the rapid development of several chromatographic methods: paper chromatography, gas chromatography, and what would become known as high-performance liquid chromatography. Since then, the technology has advanced rapidly. Researchers found that the main principles of Tsvet's chromatography could be applied in many different ways, resulting in the different varieties of chromatography described below. Advances are continually improving the technical performance of chromatography, allowing the separation of increasingly similar molecules.
=== Development of synthetic AAS === The development of muscle-building properties of testosterone was pursued in the 1940s, in the Soviet Union and in Eastern Bloc countries such as East Germany, where steroid programs were used to enhance the performance of Olympic and other amateur weight lifters. In response to the success of Russian weightlifters, the U.S. Olympic Team physician John Ziegler worked with synthetic chemists to develop an AAS with reduced androgenic effects. Ziegler's work resulted in the production of metandienone, which Ciba Pharmaceuticals marketed as Dianabol. The new steroid was approved for use in the U.S. by the Food and Drug Administration (FDA) in 1958. It was most commonly administered to burn victims and the elderly. The drug's off-label users were mostly bodybuilders and weight lifters. Although Ziegler prescribed only small doses to athletes, he soon discovered that those having used metandienone developed enlarged prostates and atrophied testes. AAS were placed on the list of banned substances of the International Olympic Committee (IOC) in 1976, and a decade later, the committee introduced "out-of-competition" doping tests because many athletes used AAS in their training period rather than during competition.
=== Industrial radiography === During World War II, Van de Graaff had used the compact generator invented with Trump to detect defects in ship hulls and ordnance for the U.S. Navy. Drawing on this application, HVEC produced 2-MeV industrial X-ray generators for non-destructive testing of manufactured goods. These units, capable of detecting flaws in thick steel sections, weighed more than two tons and were designed to operate in industrial facilities. HVEC adapted these generators to output electron beams, selling a line of industrial radiography equipment and also renting sterilization services to other companies. In 1957, Ethicon, a medical subsidiary of Johnson & Johnson, purchased an HVEC linear accelerator to sterilize surgical sutures, the first commercial medial product to use radiation processing. Sales of e-beam processing machines picked up after HVEC introduced insulating core transformers. ICTs, operating in the lower-voltage 300 keV to 2.5 MeV range, were used for crosslinking polyethylene and other polymers. W. R. Grace's Cryovac division used radiation crosslinking to produce heat-shrinkable materials for food packaging. Other companies purchased ICTs for extended to wire and cable insulation, rubber vulcanization, auto paint, textile modification, and semiconductors.
== Awards == In 2009, Amana Contracting and Steel Buildings was awarded the Dubai Quality Appreciation Program certificate for the construction field. In 2014, the company was awarded the CSR Label by The Dubai Chamber of Commerce and Industry.
Sources: en.wikipedia.org
=== Thought patterns and knowledge === Thought patterns can influence well-being positively or negatively by shaping how the world is interpreted and experienced. For example, frequent negative thoughts about past events can trigger anxiety and depressive moods. Accordingly, various psychotherapeutic and religious schools of thought propose methods and practices to promote thought patterns conducive to well-being. For example, a key element of cognitive behavior therapy is to identify and reframe automatic negative thoughts, while various Eastern religious traditions, such as Buddhism, recommend meditation and mindfulness. Related mental factors of well-being include tendencies that lead people to act against their own self-interest, such as impaired self-control in the form of addictions, and cognitive biases leading to irrational decisions. Philosophers examine how knowledge affects well-being, like when knowledge helps people avoid dangers or solve problems. It is controversial whether all forms of knowledge contribute to well-being, such as the contrast between trivial knowledge of unimportant facts and practically relevant knowledge about oneself or deep insights into general truths of the world. In addition to knowledge, many related epistemic goods contribute to well-being, such as intelligence, problem-solving skills, creativity, open-mindedness, understanding, and wisdom. The value of epistemic goods is reflected in the emphasis given to education to foster the development of the minds of students.
== Range and habitat == The neon tetra is found in the western and northern Amazon basin in southeastern Colombia, eastern Peru, and western Brazil. It lives in waters with a temperature between 20 and 28 °C (68–82 °F) and pH 4–7.5. It has a preference for acidic blackwater streams, but also occurs in transparent clearwater streams. It is not found in the whitewater rivers. UN FAO considers P. innesi an introduced species in Singapore and the United States. FAO considers its introduction to Singapore to be ecologically and socioeconomically beneficial, but it is not established there.
Diabulimia (a portmanteau of diabetes and bulimia), also known as ED-DMT1 (eating disorder-diabetes mellitus type 1) in the US or T1ED (type 1 eating disorder) in the UK, is an eating disorder in which people with type 1 diabetes deliberately give themselves less insulin than they need or stop taking it altogether for the purpose of weight loss. Diabulimia is not recognized as a formal psychiatric diagnosis in the DSM-5. Because of this, some in the medical or psychiatric communities use the phrases "disturbed eating behavior" or "disordered eating behavior" (DEB in both cases) and disordered eating (DE) are quite common in medical and psychiatric literature addressing patients who have type 1 diabetes and manipulate insulin doses to control weight along with exhibiting bulimic behavior. Diabulimia is caused by a range of factors relating to body image, the regular use of insulin, and emotional well-being. Insulin can cause weight gain, and a person who restricts insulin may lose weight. Insulin restriction can lead to the common symptoms of uncontrolled hyperglycemia, which risks complications and a shorter life expectancy. Treatment involves cognitive behavioral therapy, and other support services offered by a multidisciplinary team who work both in diabetes medicine and on eating disorders. Diabulimia is most common in young people, and most of the severe cases tend to occur in women. Research into effective management strategies is ongoing, with a growing medical consensus on the importance of early intervention with specialist teams.
In biology, homeostasis (in British English also homoeostasis) is the process by which living organisms maintain relatively stable internal physical and chemical conditions despite changes in their internal or external environment. Body temperature, blood glucose, blood pressure, fluid balance, levels of oxygen and carbon dioxide in the blood, pH, and the concentrations of ions such as sodium, potassium, and calcium are all homeostatically regulated variables. These variables are generally maintained within physiological ranges rather than at absolutely constant values; set points for some regulated variables may also change, as occurs with circadian variation in body temperature or during fever. Homeostatic regulation commonly operates through negative feedback. Sensors detect changes in a regulated variable, control mechanisms coordinate an appropriate response, and effectors act to counter the deviation. Regulation can involve the nervous system, endocrine system, and organs: the kidneys, lungs, liver, and pancreas, as well as cellular mechanisms such as the regulation of gene expression. Predictive homeostasis consists of anticipatory responses to expected changes, but these require feedback mechanisms to correct deviations. Together, homeostatic processes maintain conditions in which metabolism and other physiological functions can occur. The concept of regulation of the internal environment was developed in the 19th century by the French physiologist Claude Bernard, and the term homeostasis was coined by the American physiologist Walter Bradford Cannon in 1926.
Brian Niccol, chair and CEO of Starbucks Richard Allison, former CEO of Domino's Pizza Andrew Campion, COO of Nike, Inc. Beth Ford, CEO of Land O'Lakes Jørgen Vig Knudstorp, executive chairman of LEGO Group Marissa Mayer, former president and CEO of Yahoo! Neal Mohan, CEO of YouTube Dambisa Moyo, Co-principal of Versaca Investments Daniel Servitje, CEO of Grupo Bimbo Mike Sievert, former CEO of T-Mobile US Wei Zhang, former president of Alibaba Pictures Group Howard Schultz, president and former CEO of Starbucks
Sources: en.wikipedia.org
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.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
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.