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 2025-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
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 |
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.
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.
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.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
=== Andy: Get The Poison Out === First aired: 4 November 2010 Meet Andy, the self-appointed king of Fresno. He is an obnoxious bully who makes life miserable for his victims, Steven and Taylor. He also makes the biggest mistake of calling out Mayhem, so Mayhem brings out "the greatest fighter he has ever known" to take care of Andy. That fighter turns out to be Mayhem himself. After easily being tapped out 5 times in the first round and knocked out in the second round, Steven and Taylor won $10,000. After the fight, Mayhem tells a humbled Andy that he had to deal with bullies most of his life and implores him to change his ways because he eventually will come across someone that is bigger, badder and meaner than Andy himself.
== Function == Tendon cells are primarily responsible for the production and maintenance of the tendon extracellular matrix (ECM), which consists mainly of collagen fibers. These cells are involved in synthesizing collagen and other ECM components that provide tendons with tensile strength. Tendon cells also participate in remodeling the ECM in response to mechanical stress and injury.
=== Etymology === Although according to the Oxford English Dictionary, the term "beriberi" comes from a Sinhalese phrase meaning "weak, weak" or "I cannot, I cannot", the word being duplicated for emphasis, the origin of the phrase is questionable. It has also been suggested to come from Hindi, Arabic, and a few other languages, with many meanings like "weakness", "sailor", and even "sheep". Such suggested origins were listed by Heinrich Botho Scheube, among others. Edward Vedder wrote in his book Beriberi (1913) that "it is impossible to definitely trace the origin of the word beriberi". The word berbere was used in writing at least as early as 1568 by Diogo do Couto, when he described the deficiency in India. Kakke (脚気), which is a Japanese synonym for thiamine deficiency, comes from the way "jiao qi" is pronounced in Japanese. "Jiao qi" is an old word used in Chinese medicine to describe beriberi. "Kakke" is supposed to have entered into the Japanese language sometime between the sixth and eighth centuries.
(2005), philanthropist, investor, activist, son of John Kluge '37 Alana Mayo (2006), president of Orion Pictures Liesel Pritzker Simmons (2006), former child actress, A Little Princess; granddaughter of businessman Abram Nicholas Pritzker, heiress to the Hyatt hotels fortune, philanthropist Wayne Ting (2006), CEO of Lime Marco Zappacosta (2007), co-founder and CEO of Thumbtack, son of Logitech founder Pierluigi Zappacosta Adam Pritzker (2008), co-founder of General Assembly, grandson of Jay Pritzker and member of the Pritzker family Jared Hecht (2009), co-founder of GroupMe Ariana Rockefeller (2009), fashion designer and great-great-granddaughter of John D. Rockefeller Zach Sims* (2012), co-founder of Codecademy Beverly Leon (2014), former midfielder of Sunderland A.F.C. Ladies, CEO of Local Civics Nicole LaPointe Jameson (2016), CEO of Evil Geniuses Korawad Chearavanont* (2017), Thai internet entrepreneur and grandson of Dhanin Chearavanont
Sources: en.wikipedia.org
Functional or homology screening strategies have been used to identify genes that produce small bioactive molecules. Functional metagenomic studies are designed to search for specific phenotypes that are associated with molecules with specific characteristics. Homology metagenomic studies, on the other hand, are designed to examine genes to identify conserved sequences that are previously associated with the expression of biologically active molecules. Functional metagenomic studies enable the discovery of novel genes that encode biologically active molecules. These assays include top agar overlay assays where antibiotics generate zones of growth inhibition against test microbes, and pH assays that can screen for pH change due to newly synthesized molecules using pH indicator on an agar plate. Substrate-induced gene expression screening (SIGEX), a method to screen for the expression of genes that are induced by chemical compounds, has also been used to search for genes with specific functions. Homology-based metagenomic studies have led to a fast discovery of genes that have homologous sequences as the previously known genes that are responsible for the biosynthesis of biologically active molecules. As soon as the genes are sequenced, scientists can compare thousands of bacterial genomes simultaneously. The advantage over functional metagenomic assays is that homology metagenomic studies do not require a host organism system to express the metagenomes, thus this method can potentially save the time spent on analyzing nonfunctional genomes.
Another formation with Tyrannosaurus remains is the Lance Formation of Wyoming. This has been interpreted as a bayou environment similar to today's Gulf Coast. The fauna was very similar to Hell Creek, but with Struthiomimus replacing its relative Ornithomimus. The small ceratopsian Leptoceratops also lived in the area. In its southern range, specifically based on remains discovered from the North Horn Formation of Utah, Tyrannosaurus rex lived alongside the titanosaur Utetitan, the ceratopsid Torosaurus and the indeterminate troodontids and hadrosaurids. Tyrannosaurus mcraeensis from the McRae Group of New Mexico coexisted with the ceratopsid Sierraceratops and possibly the titanosaur Alamosaurus. Potential remains identified as cf. Tyrannosaurus have also been discovered from the Javelina Formation of Texas, where the remains of the titanosaur (either Alamosaurus or Utetitan), the ceratopsid Bravoceratops, the pterosaurs Quetzalcoatlus and Wellnhopterus, and possible species of troodontids and hadrosaurids are found. Its southern range is thought to have been dominated by semi-arid inland plains, following the probable retreat of the Western Interior Seaway as global sea levels fell. Tyrannosaurus may have also inhabited Mexico's Lomas Coloradas Formation in Sonora. Though skeletal evidence is lacking, six shed and broken teeth from the fossil bed have been thoroughly compared with other theropod genera and appear to be identical to those of Tyrannosaurus. If true, the evidence indicates the range of Tyrannosaurus was possibly more extensive than previously believed.
== History == Pregabalin was synthesized in 1990 as an anticonvulsant that was developed as a successor to the related gabapentin. It was first synthesized by medicinal chemist Richard Bruce Silverman at Northwestern University in Evanston, Illinois. During 1988 to 1990, Ryszard Andruszkiewicz, a visiting research fellow, synthesized a series of molecules requested by Silverman. Upon testing in mouse seizure models by collaborators at Parke-Davis Pharmaceuticals, one looked particularly promising. In vitro, it activated L-glutamic acid decarboxylase, an enzyme, but this later proved to be unimportant to prevention of seizures. Silverman had originally hoped that the enzyme would increase the production of the inhibitory neurotransmitter GABA and block convulsions. After extensive development studies and clinical trials by Parke-Davis the drug was approved in the European Union in 2004. The US received FDA approval for use in treating epilepsy, diabetic neuropathic pain, and postherpetic neuralgia in December 2004. Pregabalin then appeared on the US market under the brand name Lyrica in the fall of 2005. In 2017, the FDA approved pregabalin extended-release Lyrica CR for the management of neuropathic pain associated with diabetic peripheral neuropathy, and postherpetic neuralgia. However, unlike the immediate release formulation, Lyrica CR was not approved for the management of fibromyalgia or as add-on therapy for adults with partial onset seizures.
Two mechanisms of resistance to temozolomide effects have now been described: 1) intrinsic resistance conferred by MGMT deficiency (MGMTd) and 2) intrinsic or acquired resistance through MMR deficiency (MMRd). The MGMT enzyme is the first line of repair of mismatched bases created by temozolomide. Cells are normally MGMT proficient (MGMTp) as they have an unmethylated MGMT promoter allowing the gene to be expressed normally. In this state, temozolomide induced DNA damage is able to be efficiently repaired in tumor cells (and normal cells) by the active MGMT enzyme. Cells may grow and pass through the cell cycle normally without arrest or death. However, some tumors cells are MGMT deficient (MGMTd). This is most commonly due to abnormal methylation of the MGMT gene promoter and suppression of gene expression. MGMTd has also been described to occur by promoter rearrangement. In cells with MGMTd, DNA damage by temozolomide activates the next stage of repair in cells with a proficient mismatch repair enzyme complex (MMRp). In MMRp the MMR protein complex identifies the damage and causes cells to arrest and undergo death which inhibits tumor growth. However, if cells have combined MGMTd and MMR deficiency (MGMTd + MMRd) then cells retain the induced mutations and continue to cycle and are resistant to effects of temozolomide. In gliomas and other cancers MMRd has now been reported to occur as primary MMRd (intrinsic or germline Lynch bMMRd) or as secondary MMRd (acquired - not present in the original untreated tumor).
Food processing is the transformation of agricultural products into food, or of one form of food into other forms. Food processing takes many forms, from grinding grain into raw flour to home cooking and complex industrial methods used in the making of convenience foods. Some food processing methods play important roles in reducing food waste and improving food preservation, thus reducing the total environmental impact of agriculture and improving food security. Food Processing Levels (FPL) are defined according to physical and chemical changes occurring during food treatments. FPL are required in processed food classifications, such as the Nova classification, to categorise processed foods according to their FPL for different purposes. Primary food processing is necessary to make most foods edible while secondary food processing turns ingredients into familiar foods, such as bread. Tertiary food processing results in ultra-processed foods and has been widely criticized for promoting overnutrition and obesity, containing too much sugar and salt, too little fiber, and otherwise being unhealthful in respect to dietary needs of humans and farmed animals.
Sources: en.wikipedia.org
Furthermore, myostatin has been shown to directly prevent cell cycle G1 to S phase transition by decreasing levels of cyclin-dependent kinase complex 2 (CDK2) and by increasing p21 levels. Growth of cardiomyocytes may also be hindered by myostatin-regulated inhibition of protein kinase p38 and the serine-threonine protein kinase Akt, which typically promote cardiomyocyte hypertrophy. However, increased myostatin activity only occurs in response to specific stimuli, such as in pressure stress models, in which cardiac myostatin induces whole-body muscular atrophy. Physiologically, minimal amounts of cardiac myostatin are secreted from the myocardium into serum, having a limited effect on muscle growth. However, increases in cardiac myostatin can increase its serum concentration, which may cause skeletal muscle atrophy. Pathological states that increase cardiac stress and promote heart failure can induce a rise in both cardiac myostatin mRNA and protein levels within the heart. In ischemic or dilated cardiomyopathy, increased levels of myostatin mRNA have been detected within the left ventricle. As a member of the TGF-β family, myostatin may play a role in post-infarct recovery. It has been hypothesized that hypertrophy of the heart induces an increase in myostatin as a negative feedback mechanism in an attempt to limit further myocyte growth. This process includes mitogen-activated protein kinases and binding of the MEF2 transcription factor within the promoter region of the myostatin gene.
Muscle cells (myocytes) form the active contractile tissue of the body. Muscle tissue functions to produce force and causes locomotion, movement within internal organs, and other types of motion. Muscle is formed of contractile filaments and is separated into three main types; smooth muscle, skeletal muscle and cardiac muscle. Smooth muscle has no striations when examined microscopically. It contracts slowly but maintains contractibility over a wide range of stretch lengths. It is found in such organs as sea anemone tentacles and the body wall of sea cucumbers. Skeletal muscle contracts rapidly but has a limited range of extension. It is found in the movement of appendages and jaws. Obliquely striated muscle is intermediate between the other two. The filaments are staggered and this is the type of muscle found in earthworms that can extend slowly or make rapid contractions. In higher animals striated muscles occur in bundles attached to bone to provide movement and are often arranged in antagonistic sets. Smooth muscle is found in the walls of the uterus, bladder, intestines, stomach, oesophagus, respiratory airways, and blood vessels. Cardiac muscle is found only in the heart, allowing it to contract and pump blood through the body.
==== Public response ==== The FDA's arguments for the federal prohibition of kratom have drawn both criticism and support. FDA commissioner Gottlieb responded to criticism in 2018 by stating that "The FDA has done an exhaustive review of adverse event reports, clinical literature and other sources of information related to kratom." However, in 2021, former Acting Commissioner of Food and Drugs Brett Giroir claimed that the FDA's recommendation to schedule kratom was rejected because of "embarrassingly poor evidence [and] data". The FDA's position on kratom has also been criticized by the American Kratom Association and researchers including Walter Prozialeck. Former commissioner Gottlieb continued to defend the agency's position in 2021, stating that he was convinced that kratom was fueling the U.S. opioid epidemic, though Gottlieb's partiality has been called into question as he has since gone on to become a member of the board of directors of Pfizer Inc., a company that has been heavily criticized for its sale and marketing of opioid drugs.
=== „Kurzmitteilung“ (2014) === Kurzmitteilung [Text Message] is Kermani's first text that he classified as a novel. It is dedicated to the Cologne actress Claudia Fenner, who died of a stroke in July 2005 at the age of 40. In the novel, Maike Anfang, who worked for Ford, dies on the same date and just as unexpectedly. She was supposed to organize an event together with the first-person narrator Dariusch, a freelance event manager. The initiating event of the novel is the text message that gives the book its title, in which Dariusch learns of the sudden death of Maike Anfang, whom he met only fleetingly, while on vacation. The novel narrates the first few days after Maike Anfang’s death, with the question of how to communicate appropriately about death serving as a leitmotif. The protagonist, Dariusch, is less affected by the personal loss than by the sudden confrontation with his own mortality. Although he is able to speak to the relatives of the deceased in an educated and empathetic manner, he is presented as a caricature of a dim-witted, sex-obsessed macho who ends up going on and on about his experience of an awakening in a self-discovery center in the United States.
Quest Diagnostics Incorporated is an American clinical laboratory. A Fortune 500 company, Quest operates in the United States, Puerto Rico, Mexico, and Brazil. Quest also maintains collaborative agreements with various hospitals and clinics across the globe. As of 2020, the company had approximately 48,000 employees, and it generated more than $7.7 billion in revenue in 2019. The company offers access to diagnostic testing services for cancer, cardiovascular disease, infectious disease, neurological disorders, COVID-19, and employment and court-ordered drug testing.
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.