If you have been reading about proteolysis 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 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
Naming for this compound is not fully standardised in English sources. The spelling Selanc appears in some transliterations, and catalogue entries may instead list the peptide sequence itself as the identifier. Reference material sometimes groups it with other short synthetic peptides studied for behavioural effects, which can create confusion when citations are compared. Distinguishing the exact sequence from related tuftsin analogues is therefore a practical first step when reviewing any dataset or specification sheet.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
== In the heart == In the heart, A1 receptors play roles in electrical pacing (chronotropy and dromotropy), fluid balance, local sympathetic regulation, and metabolism. When bound by adenosine, A1 receptors inhibit impulses generated in supraventricular tissue (SA node, AV node) and the Bundle of His/Purkinje system, leading to negative chronotropy (slowing of the heart rate). Specifically, A1 receptor activation leads to inactivation of the inwardly rectifying K+ current and inhibition of the inward Ca2+ current (ICa) and the 'funny' hyperpolarization-activated current (If). Adenosine agonism of A1ARs also inhibits release of norepinephrine from cardiac nerves. Norepinephrine is a positive chronotrope, inotrope, and dromotrope, through its agonism of β adrenergic receptors on pacemaker cells and ventricular myocytes. Collectively, these mechanisms lead to an myocardial depressant effect by decreasing the conduction of electrical impulses and suppressing pacemaker cells function, resulting in a decrease in heart rate. This makes adenosine a useful medication for treating and diagnosing tachyarrhythmias, or excessively fast heart rates. This effect on the A1 receptor also explains why there is a brief moment of cardiac standstill when adenosine is administered as a rapid IV push during cardiac resuscitation. The rapid infusion causes a momentary myocardial stunning effect. In normal physiological states, this serves as protective mechanisms.
=== Filesystems === Filesystem dump: A copy of the whole filesystem in block-level can be made. This is also known as a "raw partition backup" and is related to disk imaging. The process usually involves unmounting the filesystem and running a program like dd (Unix). Because the disk is read sequentially and with large buffers, this type of backup can be faster than reading every file normally, especially when the filesystem contains many small files, is highly fragmented, or is nearly full. But because this method also reads the free disk blocks that contain no useful data, this method can also be slower than conventional reading, especially when the filesystem is nearly empty. Some filesystems, such as XFS, provide a "dump" utility that reads the disk sequentially for high performance while skipping unused sections. The corresponding restore utility can selectively restore individual files or the entire volume at the operator's choice. Identification of changes: Some filesystems have an archive bit for each file that says it was recently changed. Some backup software looks at the date of the file and compares it with the last backup to determine whether the file was changed. Versioning file system: A versioning filesystem tracks all changes to a file. The NILFS versioning filesystem for Linux is an example.
=== Leukemia === James has also researched children diagnosed with leukemia in Fallon, Nevada. She originally received a grant from the United States Environmental Protection Agency to conduct this research in 2004 and presented preliminary results the following year. James speculated that the Fallon children had a metabolic predisposition to develop leukemia when exposed to environmental contaminants. She never published her final results, because she only had 20 blood samples--"not enough to reach a conclusive result."
On October 2, 2025, FIFA announced the video game FIFA Heroes, scheduled for release in 2026 on Android, iOS, Nintendo Switch, PlayStation, and Xbox platforms. In May 2026, the Football Manager 26 video game also announced the addition of licensed 2026 FIFA World Cup content. In December 2025, Netflix announced a new simulation-type game featuring the World Cup, produced by Delphi Interactive and Refactor Games. In May 2026, it was announced the Netflix-published game would be titled FIFA World Cup: Launch Edition; it was released in June 2026. In the same May 2026 announcement, FIFA also confirmed that they would adopt a non-exclusive "Digital Football" ecosystem, with games of various genres adopting the FIFA license. Alongside the new World Cup game were FIFA Heroes, FIFA Rivals, FIFA Super Soccer, Football Manager, eFootball and Rocket League, with more games joining the ecosystem in the following months.
== Childhood and education == Joseph Fruchtgarten was born in Częstochowa, Poland; his father Shama Nuta (Charles) Fruchtgarten was a grain merchant, and his mother Ella (Aisenstadt) Fruchtgarten was a French teacher. Like many other Polish Jews, the Fruchtgartens immigrated to the United States shortly before the outbreak of World War I. They lived in New York City from 1913 to 1917, and in April 1917 they moved to Minsk (then occupied by the Red Army in the midst of the Russian Civil War). Between 1917 and 1923, Fruchtgarten attended school intermittently, moving from Minsk to Siedlce to Warsaw to Berlin, and learning French, German and Latin (in addition to Polish and English). In 1923, the Fruchtgartens returned to New York and changed their name to Fruton to avoid being targets of anti-Semitism. Joseph Fruton followed his father in rejecting religion, but learned early on "not to advertise either [his] Jewishness or [his] atheism." After a few months at De Witt Clinton High School, Fruton joined the first class of students at James Madison High School. He graduated in 1927, excelling particularly in chemistry. He applied to Columbia University, and after an initial rejection—possibly because he was only 15 at the time, possibly because the school had already admitted the quota of New York Jews—his mother convinced an admissions official to reverse the decision. Inspired by the character Max Gottlieb from the Sinclair Lewis novel Arrowsmith, Fruton planned his Columbia education around becoming a scientist. The lectures and lab-work of organic chemist John M.
Sources: en.wikipedia.org
Products containing caffeine include coffee, tea, soft drinks ("colas"), energy drinks, other beverages, chocolate, caffeine tablets, other oral products, and inhalation products. According to a 2020 study in the United States, coffee is the major source of caffeine intake in middle-aged adults, while soft drinks and tea are the major sources in adolescents. Energy drinks are more commonly consumed as a source of caffeine in adolescents as compared to adults.
== Side effects == Bromazepam is similar in side effects to other benzodiazepines. The most common side effects reported are drowsiness, sedation, ataxia, memory impairment, and dizziness. Impairments to memory functions are common with bromazepam and include a reduced working memory and reduced ability to process environmental information. A 1975 experiment on healthy, male college students exploring the effects of four different drugs on learning capacity observed that taking bromazepam alone at 6 mg 3 times daily for 2 weeks impaired learning capacities significantly. In combination with alcohol, impairments in learning capacity became even more pronounced. Various studies report impaired memory, visual information processing and sensory data and impaired psychomotor performance; deterioration of cognition including attention capacity and impaired co-ordinative skills; impaired reactive and attention performance, which can impair driving skills; drowsiness and decrease in libido. Unsteadiness after taking bromazepam is, however, less pronounced than other benzodiazepines such as lorazepam. On occasion, benzodiazepines can induce extreme alterations in memory such as anterograde amnesia and amnesic automatism, which may have medico-legal consequences. Such reactions occur usually only at the higher dose end of the prescribing spectrum. Very rarely, dystonia can develop. Up to 30% treated on a long-term basis develop a form of dependence, i.e. these patients cannot stop the medication without experiencing physical or psychological benzodiazepine withdrawal symptoms.
== Medical uses == It is used to treat pulmonary arterial hypertension (PAH), pulmonary fibrosis, as well as atherosclerosis. In pediatric practice, prostacyclin is commonly used to mantain patency of the ductus arteriosus. Prostacyclins are given to people with class III or class IV PAH.
Genotypic AMR characterisation methods are, however, being increasingly used in combination with machine learning algorithms in research to help better predict phenotypic AMR from organism genotype. Optical techniques such as phase contrast microscopy in combination with single-cell analysis are another powerful method to monitor bacterial growth. In 2017, scientists from Uppsala University in Sweden published a method that applies principles of microfluidics and cell tracking, to monitor bacterial response to antibiotics in less than 30 minutes overall manipulation time. This invention was awarded the 8M£ Longitude Prize on AMR in 2024. Recently, this platform has been advanced by coupling microfluidic chip with optical tweezing to isolate bacteria with altered phenotype directly from the analytical matrix. Rapid diagnostic methods have also been trialled as antimicrobial stewardship interventions to influence the healthcare drivers of AMR. Serum procalcitonin measurement has been shown to reduce mortality rate, antimicrobial consumption and antimicrobial-related side-effects in patients with respiratory infections, but impact on AMR has not yet been demonstrated. Similarly, point of care serum testing of the inflammatory biomarker C-reactive protein has been shown to influence antimicrobial prescribing rates in this patient cohort, but further research is required to demonstrate an effect on rates of AMR. Clinical investigation to rule out bacterial infections are often done for patients with pediatric acute respiratory infections.
Sources: en.wikipedia.org
==== Affinity-based peptide biosensors ==== This kind of peptide biosensor rely on peptides that can selectively bind a target like proteins, Small molecules, or ions. These peptides often mimic natural binding motifs, receptor fragments, antibody epitopes or ligand domains. They are engineered via methods such as phage display or computational design to achieve high affinity and specificity for their targets. These biosensors are widely used for detecting proteins, toxins and biomarkers due to affinity. Because affinity interactions offer great selectivity without requiring enzymatic reactions, these biosensors are frequently utilized for detecting proteins, toxins, and biomarkers.
==== United States ==== In the United States, codeine is regulated by the Controlled Substances Act. Federal law dictates that codeine be a Schedule II controlled substance when used in products for pain relief that contain codeine alone or more than 80 mg per dosage unit. Codeine without aspirin or acetaminophen (Tylenol) is very rarely available or prescribed to discourage abuse. Tablets of codeine in combination with aspirin or acetaminophen (paracetamol) and intended for pain relief are listed as Schedule III. Cough syrups are classed as Schedule III, IV, or V, depending on formulation. For example, the acetaminophen/codeine antitussive liquid is a Schedule IV controlled substance. Some states have chosen to reclassify codeine preparations at a more restrictive schedule to lower the instances of its abuse. Minnesota, for instance, has chosen to reclassify Schedule V some codeine preparations (e.g. Cheratussin) as a Schedule III controlled substance.
The acetylation at position 3 and the conversion into a dihydromorphinone class semisynthetic (at position 14 on the morphine carbon skeleton) allows for the drug to more rapidly enter the central nervous system in greater quantity where it is de-acetylated into hydromorphone, and also converted by other processes into hydromorphinol, morphine and various other active and inactive substances; it therefore simultaneously takes advantage of two methods of increasing the effectiveness of morphine and its derivatives, those being catalytic hydrogenation (codeine into hydrocodone) and esterification (morphine into diamorphine, nicomorphine &c) in a manner not unlike to that of dihydrodiacetylmorphine.
The Somali community has been a source of many significant poets, writers, and Islamic figures over the years, a considerable proportion of whom have played a pivotal role in influencing and moulding the trajectory of Muslim scholarship and traditions, not just in the Horn of Africa but also reaching far into the Arabian Peninsula and other regions around the world. Somalia has also been called by, among others, the Canadian novelist and scholar Margaret Laurence, a "Nation of Poets" and a "Nation of Bards". Famed British explorer and writer Richard Burton wrote that many Somalis are exceptionally familiar with literature and poetry. With the adoption of the Latin alphabet in 1972 as the nation's standard orthography, numerous contemporary Somali authors have also released novels, some of which have received worldwide acclaim. Among these modern authors, Nuruddin Farah is the most renowned, receiving, among other honours, the 1998 Neustadt international prize for Literature. Faarax M.J. Cawl is another notable Somali author who is famous for his novel set in the Dervish era, Ignorance is the enemy of love. Somali poetry also thrived during this era with Hadraawi gaining national renown for his prose and poetry.
If the bottle of tequila does not state on the label that it is manufactured from 100% blue agave (no sugars added), then, by default, that tequila is a mixto (manufactured from at least 51% blue agave). Some tequila distilleries label their tequila as "made with blue agave" or "made from blue agave". The Tequila Regulatory Council has stated only tequilas distilled with 100% agave can be designated as "100% agave". Many of the higher-quality, 100% agave tequilas do not impart significant alcohol burn, and drinking them with salt and lime is likely to remove much of the flavor. These tequilas are usually sipped from a snifter glass rather than a shot glass, and savoured instead of quickly gulped. Doing so allows the taster to detect subtler fragrances and flavors that would otherwise be missed.
Sources: en.wikipedia.org
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.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.