Pro-Gly-Pro comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-04-02. Numbers and descriptions here follow the published literature rather than marketing material.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
| Property | Value | Notes |
|---|---|---|
| Solubility | Freely soluble in water | Also in aqueous buffers |
| Typical purity (HPLC) | 95 percent or higher | Lot-dependent |
| Dry powder storage | Minus 20 degrees Celsius | Sealed, dry, protected from light |
| Solution storage | 2 to 8 degrees Celsius | Short-term use |
| Identity confirmation | Mass spectrometry | ESI or MALDI-TOF |
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.
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.
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.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
=== History === Emus were first reported as having been seen by Europeans when explorers visited the western coast of Australia in 1696. This was during an expedition led by Dutch captain Willem de Vlamingh who was searching for survivors of a ship that had gone missing two years earlier. The birds were known on the eastern coast before 1788, when the first Europeans settled there. The birds were first mentioned under the name of the "New Holland cassowary" in Arthur Phillip's Voyage to Botany Bay, published in 1789 with the following description:
Methylene blue is used in endoscopic polypectomy as an adjunct to saline or epinephrine, and is used for injection into the submucosa around the polyp to be removed. This allows the submucosal tissue plane to be identified after the polyp is removed, which is useful in determining if more tissue needs to be removed or if there is a high risk for perforation. Methylene blue is also used as a dye in chromoendoscopy, and is sprayed onto the mucosa of the gastrointestinal tract to identify dysplasia, or pre-cancerous lesions. Intravenously injected methylene blue is readily released into the urine. In surgeries such as sentinel lymph node dissections, methylene blue can be used to visually trace the lymphatic drainage of tested tissues. Similarly, methylene blue is added to bone cement in orthopedic operations to provide easy discrimination between native bone and cement. Additionally, methylene blue accelerates the hardening of bone cement, increasing the speed at which bone cement can be effectively applied. Methylene blue is used as an aid to visualisation/orientation in several medical devices, including a surgical sealant film. It can also be used during gastrointestinal surgeries (such as bowel resection or gastric bypass) to test for leaks. It is sometimes used in cytopathology, in mixtures including Wright-Giemsa and Diff-Quik. It confers a blue color to both nuclei and cytoplasm, and makes the nuclei more visible. When methylene blue is "polychromed" (oxidized in solution or "ripened" by fungal metabolism, as originally noted in the thesis of Dr. D. L.
Reptiles endemic to Somalia include the Hughes' saw-scaled viper, the Southern Somali garter snake, a racer (Platyceps messanai), a diadem snake (Spalerosophis josephscorteccii), the Somali sand boa, the angled worm lizard, a spiny-tailed lizard (Uromastyx macfadyeni), Lanza's agama, a gecko (Hemidactylus granchii), the Somali semaphore gecko, and a sand lizard (Mesalina or Eremias). A colubrid snake (Aprosdoketophis andreonei) and Haacke-Greer's skink (Haackgreerius miopus) are endemic species.
==== South American plate ==== Trindade/Martin Vaz hotspot (41) 20°30′S 28°48′W, w= 1 az= 264° ±5° Fernando hotspot (9) 3°48′S 32°24′W, w= 1 az= 266° ±7° Possibly related to the Central Atlantic Magmatic Province (c. 200 Ma) Ascension hotspot (55) 7°54′S 14°18′W
Immunotherapy developed in the 1970s following the discovery of the structure of antibodies and the development of hybridoma technology, which provided the first reliable source of monoclonal antibodies. These advances allowed for the specific targeting of tumors both in vitro and in vivo. Initial research on malignant neoplasms found mAb therapy of limited and generally short-lived success with blood malignancies. Treatment also had to be tailored to each individual patient, which was impracticable in routine clinical settings. Four major antibody types that have been developed are murine, chimeric, humanised and human. Antibodies of each type are distinguished by suffixes on their name.
Sources: en.wikipedia.org
=== Tooth eruption === PTHrP is critical in intraosseous phase of tooth eruption where it acts as a signalling molecule to stimulate local bone resorption. Without PTHrP, the bony crypt surrounding the tooth follicle will not resorb, and therefore the tooth will not erupt. In the context of tooth eruption, PTHrP is secreted by the cells of the reduced enamel epithelium.
"They consist largely of Rajpoots (Rajput), who are a distinguished race among the Khiteree (Kshatriya), or Brhamins (Brahmin) We may judge of the size of these men when we are told that the height below which no recruit is taken is five feet six inches. The great proportion of the Grenadiers are six feet and upwards." The meaning of the term Indian Army changed over time, initially as an informal collective term for the armies of the three presidencies–the Bengal Army, Madras Army and Bombay Army–between 1858 and 1894. In 1895, the Indian Army began its formal existence and was the "army of the government of India", including British and Indian (sepoy) units; this arrangement lasted until 1902. Many of these troops took part in the Indian Mutiny, with the aim of reinstating the Mughal Emperor Bahadur Shah II at Delhi, partly as a result of insensitive treatment by their British officers. During this period, the Company Raj relied heavily upon the armies of Princely states to quell the rebellion.
=== Other antibiotics === Alternatives to fosfomycin include nitrofurantoin, pivmecillinam, and co-amoxiclav in oral treatment of urinary-tract infections associated with extended-spectrum beta-lactamase. In a separate study, CRE were treated with colistin, amikacin, and tigecycline, and emphasizes the importance of using gentamicin in patients undergoing chemotherapy or stem-cell therapy procedures. While colistin had shown promising activity against carbapenemase-producing isolates, more recent data suggest a resistance to it is already emerging and it will soon become ineffective. Using another antibiotic concomitantly with carbapenem can help prevent the development of carbapenem resistance. One specific study showed a higher rate of carbapenem resistance when using meropenem alone compared with combination therapy with moxifloxacin. In addition, several drugs were tested to gauge their effectiveness against CRE infections. In vitro studies have shown that rifampin has synergistic activity against carbapenem-resistant E. coli and K. pneumoniae. However, more data are needed to determine if rifampin is effective in a clinical setting. Several new agents are in development. The main areas where scientists are focusing is new β-lactamase inhibitors with activity against carbapenemases. Some of these include MK-7655, NXL104, and 6-alkylidenepenam sulfones. The exact way they affect the carbapenemases is unknown. Another experimental agent with activity against CRE is eravacycline.
== German Empire (1871–1918) == The German Empire was born out of the North German Confederation as result of the Franco-Prussian War (1870/71). The Präsidium (the Prussian king), which now had also the title Emperor, named the chancellor. Political parties: None Centre
== S == Sac6 Sla1p Srv2 (CAP) S-adenosyl-L-homocysteine hydrolase, (SAHH) Sla2p Synaptopodin Scinderin (adseverin) Synapsins Scruin Spectrin Severin Spectraplakins SVSII Shot (Short stop) Spire Shroom Smitin (Smooth Musc.Titin) Supervillin SipA Smoothelin Sucrose synthetase SipC Sra-1 Spinophilin Ssk2p Swinholide
Sources: en.wikipedia.org
=== Numbers of new drugs === Under the ODA and EU legislation, many orphan drugs have been developed, including drugs to treat glioma, multiple myeloma, cystic fibrosis, phenylketonuria, snake venom poisoning, and idiopathic thrombocytopenic purpura. The Pharmaceutical Executive opines that the "ODA is nearly universally acknowledged to be a success". Before the US Congress enacted the ODA in 1983, only 38 drugs were approved in the US specifically to treat orphan diseases. In the US, from January 1983 to June 2004, 249 orphan drugs received marketing authorization and 1,129 received different orphan drug designations, compared to fewer than ten such products in the decade prior to 1983. From 1983 until May 2010, the FDA approved 353 orphan drugs and granted orphan designations to 2,116 compounds. As of 2010, 200 of the roughly 7,000 officially designated orphan diseases have become treatable. Critics have questioned whether orphan drug legislation was the real cause of this increase, claiming that many of the new drugs were for disorders which were already being researched anyway, and would have had drugs developed regardless of the legislation, and whether the ODA has truly stimulated the production of non-profitable drugs; the act also has been criticised for allowing some pharmaceutical companies to make a large profit off drugs which have a small market but sell for a high price.
===== Nuclear Magnetic Resonance ===== To analyze the full structure of a nascent polypeptide, nuclear magnetic resonance (NMR) is used. NMR allows a dynamic view of molecules in solution and so can be used on ribosome-nascent chain complexes (RNC). Labelling of ribosomes allows the NMR data to be filtered for suspected ribosome signal and identify the signal of the nascent polypeptide.
=== Disease progression === The natural time course of a disease is often dynamic, with the tendency to become worse without treatment. Disease progression models are mainly used to understand the relationship between treatment, biomarker changes and clinical outcomes. These models describe the disease trajectory, by observing the change in the biomarker level, or the other clinically relevant endpoint that reflects the disease status, over time.
Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these. Both strontium and strontianite are named after Strontian, a village in Scotland near which the mineral was discovered in 1790 by Adair Crawford and William Cruickshank. It was identified as a new element the next year from its crimson-red flame test color. Strontium was first isolated as a metal in 1808 by Humphry Davy using the then newly discovered process of electrolysis. During the 19th century, strontium was mostly used in the production of sugar from sugar beets (see strontian process). At the peak of production of television cathode-ray tubes, as much as 75% of strontium consumption in the United States was used for the faceplate glass. With the replacement of cathode-ray tubes with other display methods, consumption of strontium has dramatically declined. While natural strontium (which is mostly the isotope strontium-88) is stable, the synthetic strontium-90 is radioactive and is one of the most dangerous components of nuclear fallout, as strontium is absorbed by the body in a similar manner to calcium. Natural stable strontium is not hazardous to health at low levels.
Commonly, a faggot consists of minced pork liver and heart, with onion and breadcrumbs. The mixture is shaped by hand into small balls, wrapped with caul fat (the omentum membrane from the pig's kidney) and baked. Faggots may also be made with beef. Another variation of the faggot is pig's fry (testicles) wrapped in pig's caul: the pig's fry and boiled onions are minced (ground) together, then mixed with breadcrumbs or cold boiled potatoes, seasoned with sage, mixed herbs and pepper, all beaten together and then wrapped in small pieces of caul to form a ball. They are baked in the oven, and usually served cold.
Sources: en.wikipedia.org
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.
Freeze-dried material is kept frozen, often at minus 20 degrees Celsius, and protected from light and moisture. Dissolved peptide is refrigerated for short-term use. Repeated freeze-thaw cycles are avoided.
A certificate of analysis typically lists purity by HPLC, the confirmed mass, appearance, and sometimes water or counter-ion content. It documents results for a specific batch. Details vary by supplier.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.