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.
Last reviewed on 2026-03-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
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.
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.
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.
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.
== External links == International Chemical Safety Card 0104 National Pollutant Inventory – Polycyclic Aromatic Hydrocarbon Fact Sheet "Lung cancer as consequence by Benzopyrene in smokers". Lung Cancer. Archived from the original on April 14, 2005. Retrieved March 5, 2005. "Levels of Benzopyrene in Burnt toasts". Guardian Unlimited, Special reports: Close encounters. Retrieved March 5, 2005. Karle, I. L. (2004). "Crystal and molecular structure of a benzo[a]pyrene-7,8-diol-9,10-epoxide N2-deoxyguanosine adduct: Absolute configuration and conformation". Proceedings of the National Academy of Sciences. 101 (6): 1433–1438. Bibcode:2004PNAS..101.1433K. doi:10.1073/pnas.0307305101. PMC 341736. PMID 14757823.
expression vector Also expression construct. A type of vector, usually a plasmid or viral vector, designed specifically for the expression of a transgene insert in a target cell, rather than for some other purpose such as cloning.
Usually, the p38 within the dendritic cell expresses TLR 4 (toll-like receptor 4), which is activated through the ligand LPS (lipopolysaccharide). This causes the p38 MAPK to be phosphorylated. This phosphorylation activates the p38 MAPK to begin producing IL-10 and IL-12. When the dendritic cells are chronically exposed to morphine during their differentiation process and then treated with LPS, the production of cytokines is different. Once treated with morphine, the p38 MAPK does not produce IL-10, instead favoring the production of IL-12. The exact mechanism through which the production of one cytokine is increased in favor over another is not known. Most likely, the morphine causes increased phosphorylation of the p38 MAPK. Transcriptional level interactions between IL-10 and IL-12 may further increase the production of IL-12 once IL-10 is not being produced. This increased production of IL-12 causes increased T-cell immune response. Further studies on the effects of morphine on the immune system have shown that morphine influences the production of neutrophils and other cytokines. Since cytokines are produced as part of the immediate immunological response (inflammation), it has been suggested that they may also influence pain. In this way, cytokines may be a logical target for analgesic development. Recently, one study has used an animal model (hind-paw incision) to observe the effects of morphine administration on the acute immunological response. Following the hind-paw incision, pain thresholds and cytokine production were measured.
Veterinary medicine was, for the first time, truly separated from human medicine in 1761, when the French veterinarian Claude Bourgelat founded the world's first veterinary school in Lyon, France. Before this, medical doctors treated both humans and other animals. Modern scientific biomedical research (where results are testable and reproducible) began to replace early Western traditions based on herbalism, the Greek "four humours" and other such pre-modern notions. The modern era really began with Edward Jenner's discovery of the smallpox vaccine at the end of the 18th century (inspired by the method of variolation originated in ancient China), Robert Koch's discoveries around 1880 of the transmission of disease by bacteria, and then the discovery of antibiotics around 1900. The post-18th century modernity period brought more groundbreaking researchers from Europe. From Germany and Austria, doctors Rudolf Virchow, Wilhelm Conrad Röntgen, Karl Landsteiner and Otto Loewi made notable contributions. In the United Kingdom, Alexander Fleming, Joseph Lister, Francis Crick and Florence Nightingale are considered important. Spanish doctor Santiago Ramón y Cajal is considered the father of modern neuroscience. From New Zealand and Australia came Maurice Wilkins, Howard Florey, and Frank Macfarlane Burnet. Others that did significant work include William Williams Keen, William Coley, James D.
The NHS questioned the benefits of the medication for depression and claimed that it was too expensive. People already using esketamine were allowed to complete treatment if their doctors considered this necessary. Esketamine is approved in the United States for and shows promise as a rapid-acting monotherapy for treatment-resistant depression, but evidence is currently limited to a single trial. It is an effective and generally safe long-term treatment for adults with treatment-resistant depression, feasible in outpatient settings; optimal oral antidepressant combinations and predictive biomarkers need further research. Spravato debuted at a cost of treatment of US$32,400 per year when it launched in the United States in March 2019. The Institute for Clinical and Economic Review (ICER), which evaluates cost effectiveness of drugs analogously to the National Institute for Health and Care Excellence (NICE) in the United Kingdom, declined to recommend esketamine for depression due to its steep cost and modest efficacy, deeming it not sufficiently cost-effective. Esketamine is the second drug to be approved for treatment-resistant depression by the FDA, following olanzapine/fluoxetine (Symbyax) in 2009. Other agents, like the atypical antipsychotics aripiprazole (Abilify) and quetiapine (Seroquel), have been approved for use in the adjunctive therapy of major depressive disorder in people with a partial response to treatment.
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== Use and effects == In his book PiHKAL (Phenethylamines I Have Known and Loved) and other publications, Alexander Shulgin and colleagues stated that doses of 1 to 3 mg orally produced clear threshold effects and that it was active at a dose of slightly more than twice that of DOM. It was stated that 10 mg DOBU was required to produce hallucinogenic effects. The drug's duration was listed as "very long". There was limited investigation of its qualitative effects. However, in PiHKAL, at the assessed doses of 2.2 mg and 2.8 mg, it was described as producing paresthesia and difficulty sleeping with few other effects. The effects of higher doses of DOBU have not been described beyond them producing hallucinogenic effects.
=== November === November 1 The U.S. Supreme Court begins its arguments about the Texas Heartbeat Act. Kenosha unrest shooting: The trial of Kyle Rittenhouse begins in Kenosha. November 2 New Jersey and Virginia gubernatorial elections are held. Republican Glenn Youngkin wins the Virginia race, while Democrat Phil Murphy wins re-election in the New Jersey race. Republican Winsome Sears wins the Virginia lieutenant governor's race and will become the first black and first female lieutenant governor of the state of Virginia. A special election is held in Ohio to fill a vacancy in its 11th congressional district left by Marcia Fudge when she resigned to become President Biden's Secretary of Housing and Urban Development. Democrat Shontel Brown wins with 81,636 of the 103,565 votes cast (78.8%). Another special election is held in Ohio to fill a vacancy in its 15th congressional district due to the resignation of Steve Stivers effective May 15 to become president and CEO of the Ohio Chamber of Commerce. Republican Mike Carey wins with 93,255 of the 160,012 votes cast (58.3%). The Atlanta Braves win the 2021 World Series, defeating the Houston Astros. Las Vegas Raiders wide receiver Henry Ruggs III is involved in an automobile accident where a 23-year-old woman is killed. At the time of the crash, Ruggs was driving 120 mph (190 km/h). He was also over double the legal intoxication level as well. The Raiders immediately cut him later that day.
=== Legal === This technique is also used for detection of illicit drugs in various samples. The most common method of drug detection has been an immunoassay. This method is much more convenient. However, convenience comes at the cost of specificity and coverage of a wide range of drugs, therefore, HPLC has been used as well as an alternative method. As HPLC is a method of determining (and possibly increasing) purity, using HPLC alone in evaluating concentrations of drugs was somewhat insufficient. Therefore, HPLC in this context is often performed in conjunction with mass spectrometry. Using liquid chromatography-mass spectrometry (LC-MS) instead of gas chromatography-mass spectrometry (GC-MS) circumvents the necessity for derivitizing with acetylating or alkylation agents, which can be a burdensome extra step. LC-MS has been used to detect a variety of agents like doping agents, drug metabolites, glucuronide conjugates, amphetamines, opioids, cocaine, BZDs, ketamine, LSD, cannabis, and pesticides. Performing HPLC in conjunction with mass spectrometry reduces the absolute need for standardizing HPLC experimental runs.
5S rRNA is transcribed by RNA polymerase III. The 18S rRNA in most eukaryotes is in the small ribosomal subunit, and the large subunit contains three rRNA species (the 5S, 5.8S and 28S in mammals, 25S in plants, rRNAs). In flies, the large subunit contains four rRNA species instead of three with a split in the 5.8S rRNA that presents a shorter 5.8S subunit (123 nt) and a 30 nucleotide subunit named the 2S rRNA. Both fragments are separated by an internally transcribed spacer of 28 nucleotides. Since the 2S rRNA is small and highly abundant, its presence can interfere with construction of sRNA libraries and compromise the quantification of other sRNAs. The 2S subunit is retrieved in fruit fly and dark-winged fungus gnat species but absent from mosquitoes. The tertiary structure of the small subunit ribosomal RNA (SSU rRNA) has been resolved by X-ray crystallography. The secondary structure of SSU rRNA contains 4 distinct domains—the 5', central, 3' major and 3' minor domains. A model of the secondary structure for the 5' domain (500-800 nucleotides) is shown.
Sources: en.wikipedia.org
== History == The band was launched by vocalist Thomas Anselmi and guitarist Christian Thorvaldson, former members of the short-lived and controversial band Slow, with new bassist Eric Marxsen and drummer Pete Bourne. The band was formed in 1987, when Anselmi and Thorvaldson settled on that name after having collaborated under the short-lived band names Mo and Christian Thorvaldson's Freeze-Dried Dog since the demise of Slow. Initially, the band spelled its name as the symbol ©, pronounced as "Circle C". Under that name, they released a self-titled debut album via Geffen Records in 1991. That album sold poorly, and the band was dropped from Geffen. After a few years of struggling to continue in the music industry, they were signed to BMG Music, releasing their second album Love Story in 1996 under the name Copyright. The singles "Transfiguration" and "Radio" were released from that album. Love Story was a shortlisted Juno Award nominee for Best Alternative Album at the Juno Awards of 1998. The album The Hidden World followed in 2001, with the song "Rock Machine" being released as a single. The band disbanded not long after.
The insulin transduction pathway is a biochemical pathway by which insulin increases the uptake of glucose into fat and muscle cells and reduces the synthesis of glucose in the liver and hence is involved in maintaining glucose homeostasis. This pathway is also influenced by fed versus fasting states, stress levels, and a variety of other hormones. When carbohydrates are consumed, digested, and absorbed the pancreas detects the subsequent rise in blood glucose concentration and releases insulin to promote uptake of glucose from the bloodstream. When insulin binds to the insulin receptor, it leads to a cascade of cellular processes that promote the usage or, in some cases, the storage of glucose in the cell. The effects of insulin vary depending on the tissue involved, e.g., insulin is the most important in the uptake of glucose by Skeletal muscle and adipose tissue. This insulin signal transduction pathway is composed of trigger mechanisms (e.g., autophosphorylation mechanisms) that serve as signals throughout the cell. There is also a counter mechanism in the body to stop the secretion of insulin beyond a certain limit. Namely, those counter-regulatory mechanisms are glucagon and epinephrine. The process of the regulation of blood glucose (also known as glucose homeostasis) also exhibits oscillatory behavior. On a pathological basis, this topic is crucial to understanding certain disorders in the body such as diabetes, hyperglycemia and hypoglycemia.
== AFL career == Fletcher was recruited by the Essendon Football Club in the 1992 National Draft. He played his first senior game against Carlton in his senior year of high school at Penleigh and Essendon Grammar School. Right from the get-go, Fletcher proved to be a highly impactful player. At 18 years old, he won a Longest Kick competition, a highly desirable trait that would serve him well for the next 22 years. He was a key member of the 1993 premiership team in his first AFL season, a team which is often referred to as the "Baby Bombers". Fletcher also played in the 2000 premiership team, a year in which he also won the Crichton Medal as Essendon's best and fairest and was selected in the All-Australian team.
== Methodology == Category 1: Stability (weighted 25% of total) Prevalence of summary offense Prevalence of violent crime Threat of terrorism Threat of war Threat of civil disorder Category 2: Healthcare (20%) Availability of private health care Quality of private healthcare Availability of publicly funded health care Quality of publicly funded health care Availability of over-the-counter drug World Bank's general health care indicators Category 3: Culture & Environment (25%) Humidity, temperature rating Discomfort of climate to travelers Transparency International's level of corruption Social or religious restrictions Level of censorship Sporting availability from 3 sport indicators Cultural availability from 4 cultural indicators Food and drink from 4 cultural indicators Consumer goods and services from product availability Category 4: Education (10%) Availability of private education Quality of private education World Bank's state school indicators Category 5: Infrastructure (20%) Street network quality Public transport quality International transportation service quality Availability of good quality housing Energy provision quality Water provision quality Telecommunications quality
=== Space science and planetary research === Space science and planetary research at the University of Arizona are largely conducted through the Lunar and Planetary Laboratory (LPL), which has led or contributed to numerous NASA missions. The university received more than $325 million for the LPL to lead NASA's 2007–08 Phoenix Mars Mission, which explored the Martian Arctic. It later received another $800 million for the OSIRIS-REx mission, the first mission in U.S. history to collect a sample from an asteroid. The LPL's contributions to the Cassini mission orbiting Saturn were larger than those of any other university in the world. University researchers designed and operated the spacecraft's atmospheric radiation and imaging investigations. The university also operates the HiRISE camera aboard the Mars Reconnaissance Orbiter. The spacecraft reached Mars in March 2006 after traveling 300 million miles. The University of Arizona-designed camera was led by planetary scientist Alfred McEwen, the project's principal investigator. HiRISE captured high-resolution images of the planet. In 2011, University of Arizona alumnus and planetary scientist Lujendra Ojha and his research team used HiRISE imagery to identify evidence of liquid water on the surface of Mars. NASA confirmed the discovery in 2015. The university receives more NASA grants annually than the next nine top NASA-Jet Propulsion Laboratory-funded universities combined. In August 2007, the University of Arizona, under the direction of planetary scientist Peter Smith, led the Phoenix Mars Mission.
Sources: en.wikipedia.org
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
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.