This is a working overview of Pro-Gly-Pro, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-06-22 and is reviewed periodically as new material appears.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
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.
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.
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.
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.
NASA spin-off technologies are commercial products and services which have been developed with the help of NASA, through research and development contracts, such as Small Business Innovation Research (SBIR) or STTR awards, licensing of NASA patents, use of NASA facilities, technical assistance from NASA personnel, or data from NASA research. Information on new NASA technology that may be useful to industry is available in periodical and website form in "NASA Tech Briefs", while successful examples of commercialization are reported annually in the NASA publication Spinoffs. The publication has documented more than 2,000 technologies over time. In 1979, notable science fiction author Robert A. Heinlein helped bring awareness to the spin-offs when he was asked to appear before Congress after recovering from one of the earliest known vascular bypass operations to correct a blocked artery. In his testimony, reprinted in his 1980 book Expanded Universe, Heinlein claimed that four NASA spin-off technologies made the surgery possible, and that they were only a few from a long list of NASA spin-off technologies from space development. Since 1976, the NASA Technology Transfer Program has connected NASA resources to private industry, referring to the commercial products as spin-offs. Well-known products that NASA claims as spin-offs include memory foam (originally named temper foam), freeze-dried food, firefighting equipment, emergency "space blankets", DustBusters, cochlear implants, LZR Racer swimsuits, and CMOS image sensors.
Ultraviolet lamps are used to sterilize workspaces and tools used in biology laboratories and medical facilities. Commercially available low-pressure mercury-vapor lamps emit about 86% of their radiation at 254 nanometers (nm), with 265 nm being the peak germicidal effectiveness curve. UV at these germicidal wavelengths damage a microorganism's DNA/RNA so that it cannot reproduce, making it harmless, (even though the organism may not be killed). Since microorganisms can be shielded from ultraviolet rays in small cracks and other shaded areas, these lamps are used only as a supplement to other sterilization techniques. UVC LEDs are relatively new to the commercial market and are gaining in popularity. Due to their monochromatic nature (±5 nm) these LEDs can target a specific wavelength needed for disinfection. This is especially important knowing that pathogens vary in their sensitivity to specific UV wavelengths. LEDs are mercury free, instant on/off, and have unlimited cycling throughout the day. Disinfection using UV radiation is commonly used in wastewater treatment applications and is finding an increased usage in municipal drinking water treatment. Many bottlers of spring water use UV disinfection equipment to sterilize their water. Solar water disinfection has been researched for cheaply treating contaminated water using natural sunlight. The UVA irradiation and increased water temperature kill organisms in the water. Ultraviolet radiation is used in several food processes to kill unwanted microorganisms.
The king cobra is not considered aggressive. It usually avoids humans and slinks off when disturbed, but is known to aggressively defend incubating eggs and attack intruders rapidly. When alarmed, it raises the front part of its body, extends the hood, shows the fangs and hisses loudly. Wild king cobras encountered in Singapore appeared to be placid, but reared up and struck in self defense when cornered. The king cobra can be easily irritated by closely approaching objects or sudden movements. When raising its body, the king cobra can still move forward to strike with a long distance, and people may misjudge the safe zone. It can deliver multiple bites in a single attack. The hiss of the king cobra is a much lower pitch than many other snakes and many people thus liken its call to a "growl" rather than a hiss. While the hisses of most snakes are of a broad-frequency span ranging from roughly 3,000 to 13,000 Hz with a dominant frequency near 7,500 Hz, king cobra growls consist solely of frequencies below 2,500 Hz, with a dominant frequency near 600 Hz, a much lower-pitched frequency closer to that of a human voice. Comparative anatomical morphometric analysis has led to a discovery of tracheal diverticula that function as low-frequency resonating chambers in king cobra and its prey, the rat snake, both of which can make similar growls.
As of April 2024, the flow of cash from Novo's weight-loss drugs was continuing to solidify its status as the most valuable company in Europe, to the point that economists were worried that Denmark might come down with Dutch disease (that is, a country that does only one thing well and nothing else). The company's market capitalization of $570 billion remained larger than the entire economy of Denmark, its $2.3 billion income tax bill for 2023 made it the largest taxpayer in the country, and its rapid growth was driving nearly all of the expansion of Denmark's economy. The company had started to move away from its traditional focus on diabetes care towards a more ambitious mission to "defeat serious chronic diseases", and towards that end, hired over 10,000 people in 2023 alone. To effectively manage the rapid expansion of its workforce while maintaining its traditional corporate culture, the Novo Nordisk Way, the company put over 400 senior executives through a leadership development program called NNX, which stands for Novo Nordisk Next. In May 2024, the company announced it would acquire Austrian fluid management service business, Single Use Support. In June 2024, the company announced plans to build a new production plant in Clayton, North Carolina, at a cost of $4.1 billion. It will be the company's fourth in the state of North Carolina and used for production of semaglutide products Ozempic and Wegovy. The company also announced plans to acquire three US-based Catalent sites in to increase production supply.
== C == C-T scan (computed tomography scan) – cachexia – Canadian Foundation for AIDS Research – candida – candidiasis – carcinogen – CAT scan – CCR5 – CD4 (T4) or CD4 + cells – CDC National Prevention Information Network (CDC-NPIN) – cell lines – cell-mediated immunity (CMI) – cellular immunity – Centers for Disease Control and Prevention (CDC) – Centers for Medicare and Medicaid Services (CMS) – central nervous system – cerebrum – cerebrospinal fluid (CSF) – cervical cancer – cervical dysplasia – cervical intraepithelial neoplasia (CIN1, CIN2, CIN3) – cervix – chancroid – chemokines – chemoprophylaxis – chemotherapy – Chlamydia – chronic idiopathic demyelinating polyneuropathy (CIPD) – circumoral paresthesia – clade – clinical endpoint – clinical latency – clinical practice guidelines – clinical trial – clinicaltrials.gov – cloning – CMS – CMV – CNS – co-receptors – coccidioidomycosis – codon – cofactors – cognitive impairment – cohort – colitis – combination therapy – community planning – Community Programs for Clinical Research on AIDS (CPCRA) – community-based clinical trial (CBCT) – community-based organization (CBO) – compassionate use – complement – complement cascade – complementary and alternative therapy – complete blood count (CBC) – computed tomography scan (C-T scan) – concomitant drugs – condyloma – condyloma acuminatum – contagious – contraindication – controlled trials – core – core protein – correlates of immunity/correlates of protection – creatinine – cross-resistance – cryotherapy – cryptococcal meningitis – cryptococcosis – Cryptococcus neoformans – cryptosporidiosis – Cryptosporidium – CSF – CTL – cutaneous – CXCR4 – cytokines – cytomegalovirus (CMV) – Cytomegalovirus retinitis – cytopenia – cytotoxic – cytotoxic T lymphocyte (CTL)
Sources: en.wikipedia.org
=== Origin of antiviral resistance === The genetic makeup of viruses is constantly changing, which can cause a virus to become resistant to currently available treatments. Viruses can become resistant through spontaneous or intermittent mechanisms throughout the course of an antiviral treatment. Immunocompromised patients, more often than immunocompetent patients, hospitalized with pneumonia are at the highest risk of developing oseltamivir resistance during treatment. Subsequent to exposure to someone else with the flu, those who received oseltamivir for "post-exposure prophylaxis" are also at higher risk of resistance. The mechanisms for antiviral resistance development depend on the type of virus in question. RNA viruses have high error rates during genome replication because RNA polymerases lack proofreading activity. RNA viruses also have small genome sizes that are typically less than 30 kb, which allow them to sustain a high frequency of mutations. The likelihood of mutations is exacerbated by the speed with which viruses reproduce, which provides more opportunities for mutations to occur in successive replications. Billions of viruses are produced every day during the course of an infection, with each replication giving another chance for mutations that encode for resistance to occur. Multiple strains of one virus can be present in the body at one time, and some of these strains may contain mutations that cause antiviral resistance.
=== Nuclear magnetic resonance spectroscopy === Metal carbonyls are often characterized by 13C NMR spectroscopy. To improve the sensitivity of this technique, complexes are often enriched with 13CO. Typical chemical shift range for terminally bound ligands is 150 to 220 ppm. Bridging ligands resonate between 230 and 280 ppm. The 13C signals shift toward higher fields with an increasing atomic number of the central metal. NMR spectroscopy can be used for experimental determination of the fluxionality. The activation energy of ligand exchange processes can be determined by the temperature dependence of the line broadening.
Modified atmosphere/modified humidity (MA/MH) packaging is a technology used to preserve the quality of fresh produce so that it can be sold to markets far away from where it is grown, extend the marketing period, and to help suppliers reduce food waste within the cold chain. Commercial examples of MA/MH include sea freight of Galia and cantaloupe melons from Central and South America to Europe (a 21-day journey) and North America (a 7-day journey); transport of white asparagus from fields in Peru to markets in Western Europe (a 20-day journey by land and sea); and trucking of cherries from orchards in Turkey to supermarkets in the UK (a 7-day journey).
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Sources: en.wikipedia.org
== Applications == The IM-MS technique can be used for analyzing complex mixtures based on differing mobilities in an electric field. The gas phase ion structure can be studied using IM-MS through measurement of the CCS and comparison with CCS of standard samples or CCS calculated from molecular modelling. The signal-to-noise ratio is obviously improved because the noise can be physically separated with signal in IM-MS. In addition, isomers can be separated if their shapes are different. The peak capacity of IM-MS is much larger than MS so more compounds can be found and analyzed. This character is very critical for -omics study which requires analyzing as many compounds as possible in a single run. It has been used in the detection of chemical warfare agents, detection of explosives, in proteomics for the analysis of proteins, peptides, drug-like molecules and nano particles. Moreover, IM-MS can be used to monitor isomeric reaction intermediates and probe their kinetics. Recently, microscale FAIMS has been integrated with electrospray ionization MS and liquid chromatography MS to rapidly separate ions in milliseconds prior to mass analysis. The use of microscale FAIMS in electrospray ionization MS and liquid chromatography MS can significantly improve peak capacity and signal-to-noise for a range of applications including proteomics, and pharmaceutical analysis. Recently, gas phase ion activation methods have been used to gain new insights into complex structures.
The first refrigerator to see widespread use was the General Electric "Monitor-Top" refrigerator introduced in 1927, so-called, by the public, because of its resemblance to the gun turret on the ironclad warship USS Monitor of the 1860s. The compressor assembly, which emitted a great deal of heat, was placed above the cabinet, and enclosed by a decorative ring. Over a million units were produced. As the refrigerating medium, these refrigerators used either sulfur dioxide, which is corrosive to the eyes and may cause loss of vision, painful skin burns and lesions, or methyl formate, which is highly flammable, harmful to the eyes, and toxic if inhaled or ingested. The introduction of Freon in the 1920s expanded the refrigerator market during the 1930s and provided a safer, low-toxicity alternative to previously used refrigerants. Separate freezers became common during the 1940s; the term for the unit, popular at the time, was deep freeze. These devices, or appliances, did not go into mass production for use in the home until after World War II. The 1950s and 1960s saw technical advances like automatic defrosting and automatic ice making. More efficient refrigerators were developed in the 1970s and 1980s, even though environmental issues led to the banning of very effective (Freon) refrigerants. Early refrigerator models (from 1916) had a cold compartment for ice cube trays.
=== Limited cooking time === Due to the difficulty of carrying large amounts of cooking fuel, campers often require their meals to be cooked in a short amount of time (5–20 minutes). Many campers prefer a ‘just add boiling water’ method of cooking, while others enjoy a more involved, and therefore often higher quality meal. The amount of cooking time can be disregarded if campers can cook over a campfire, however, due to the possibility of a burn ban being in place, campers do not often rely on this option.
Tulips are called lale in Turkish (from the Persian: لاله, romanized: laleh from لال lal 'red'). When written in Arabic letters, lale has the same letters as Allah, which is why the flower became a holy symbol. It was also associated with the House of Osman, resulting in tulips being widely used in decorative motifs on tiles, mosques, fabrics, crockery, etc. in the Ottoman Empire. The tulip was seen as a symbol of abundance and indulgence. The era during which the Ottoman Empire was wealthiest is often called the Tulip era or Lale Devri in Turkish. Tulips became popular garden plants in the east and west, but, whereas the tulip in Turkish culture was a symbol of paradise on earth and had almost a divine status, in the Netherlands it represented the briefness of life. By contrast to other flowers such as the coneflower or lotus flower, tulips have historically been capable of genetically reinventing themselves to suit changes in aesthetic values. In his 1597 herbal, John Gerard says of the tulip that "nature seems to play more with this flower than with any other that I do know". When in the Netherlands, beauty was defined by marbled swirls of vivid contrasting colours, the petals of tulips were able to become "feathered" and "flamed". However, in the 19th century, when the English desired tulips for carpet bedding and massing, the tulips were able to once again accommodate this by evolving into "paint-filled boxes with the brightest, fattest dabs of pure pigment".
Most modern cultures mark the location of the body with a headstone. This serves two purposes. First, the grave will not accidentally be exhumed. Second, headstones often contain information or tributes to deceased. This is a form of remembrance for loved ones; it can also be viewed as a form of immortality, especially in cases of famous people's graves. Such monumental inscriptions may subsequently be useful to genealogists and family historians. In many cultures graves will be grouped, so the monuments make up a necropolis, a "city of the dead" paralleling the community of the living.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.