The short version of Enkephalinase fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-12-17. Anything still debated is marked as such rather than presented as settled.
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.
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.
| 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 |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
== Company history == BIA Separations was formed in 1998 by a group of scientists in Ljubljana, Slovenia to commercialize a new chromatographic resin based on monolith technology. Monolithic resin was developed independently by three different laboratories in late 1980s led by Hjertén, Švec and Tennikova. The company was one of the few Slovenian companies to receive venture capital funding at that time-Horizonte Venture Management realizing the potential of monoliths made the initial investment in the company. During that year, BIA Separations released its first commercial product marketed under the trade name of CIM (Convective Interaction Media). The new technique was named HPMC (High Performance Monolith Chromatography). During the 1999 and 2000s, the company promoted this new platform technology to the scientific and business community and registered several patents. In 2007 the company headquarters moved to Villach, Austria. In 2011 BIA Separations entered a strategic partnership with Japan Synthetic Rubber Corporation, a Japanese company producing synthetic materials. A strategic partnership agreement with Showa Denko K.K. (SDK) was signed in 2012.
Janis, made by Video Arts Television 4 November A Brush with the Greens, about environmental consumer products; the consumer products company Creightons of Billingshurst was looking at developing new products and had an environmental audit by John Elkington; deep ecology; the PA Consulting Group; the Predicasts database; the CEGB wind energy demonstration site in west Wales at Carmarthen Bay Power Station; a million tonnes of plastic packaging waste was caused in the UK each year; separating plastic waste would allow much more recycling of household plastics; the Greater Manchester Waste Disposal Authority; the Purfleet Board plant in Essex, which itself was powered by landfill gas through a Ruston Gas Turbines TB5000 CHP plant, which closed in 2004; a focus group (four women) takes place, where the product designers sit behind a two-way mirror, with new toothpaste designs placed on a mood board. Narrated by wine critic Jancis Robinson, produced by Mike Cockburn, directed by David Sharp, made by London Scientific Films 11 November Patently Obvious?, about acquiring patents in the UK; scenes from the 1951 The Man in the White Suit and The Dam Busters; Barry Fox of New Scientist, and the invention of FM by Edwin Howard Armstrong; Jeremy Phillips of Queen Mary and Westfield College; computer software cannot be patented; Peter Chilvers, who disputed an American patent; the British Technology Group; Richard Taylor and Paul Kellar of Quantel; in the European Patent Organisation, the UK had 6% of patents but the US and Germany had 25% each; Robert Donat in 1951 The Magic Box.
In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which all the carbon–carbon bonds are single. Alkanes have the general chemical formula CnH2n+2 and therefore range in complexity from the simplest case of methane (CH4), where n = 1, to arbitrarily large and complex molecules, like hexacontane (C60H122) or 4-methyl-5-(1-methylethyl) octane, an isomer of dodecane (C12H26). The International Union of Pure and Applied Chemistry (IUPAC) defines alkanes as "acyclic branched or unbranched hydrocarbons having the general formula CnH2n+2, and therefore consisting entirely of hydrogen atoms and saturated carbon atoms". However, some sources use the term to denote any saturated hydrocarbon, including those that are either monocyclic (i.e. the cycloalkanes) or polycyclic, despite them having a distinct general formula (e.g. cycloalkanes are CnH2n). In an alkane, each carbon atom is sp3-hybridized with 4 sigma bonds (either C–C or C–H), and each hydrogen atom is joined to one of the carbon atoms (in a C–H bond). The longest series of linked carbon atoms in a molecule is known as its carbon skeleton or carbon backbone. The number of carbon atoms may be considered as the size of the alkane. One group of the higher alkanes are waxes, solids at standard ambient temperature and pressure (SATP), for which the number of carbon atoms in the carbon backbone is greater than about 17.
Eteplirsen (brand name Exondys 51) is a medication to treat, but not cure, some types of Duchenne muscular dystrophy (DMD), caused by a specific mutation. Eteplirsen only targets specific mutations and can be used to treat about 14% of DMD cases. Eteplirsen is a form of antisense therapy. Eteplirsen was developed by Steve Wilton, Sue Fletcher and colleagues at the University of Western Australia and commercialized by Sarepta Therapeutics. After a controversial debate surrounding the drug's efficacy, during which two FDA review panel members resigned in protest, eteplirsen received accelerated approval from the US Food and Drug administration in late 2016. The Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) refused to authorize the use of eteplirsen.
Sources: en.wikipedia.org
== History and operations == The company is owned, with a majority share, by Hero Brands, based in Glasgow, Scotland, which also owns Hawaiian food brand Island Poké and salad restaurant Choppaluna. As of January 2024, the chain operates in six countries; the United Kingdom, United Arab Emirates, Sweden, Canada, United States, and Saudi Arabia. The company claims to trace its heritage to a restaurant in Berlin, Germany in 1989. It developed its offering over the following decade, until Farshad Abbaszadeh launched the first "Doner Kebab" franchise in Dubai in 2013. It then opened its first UK restaurant in 2015, expanding to seven by the end of 2017. In 2014, the franchise won the award "Best UAE Franchise Brand" at the 2014 MENAFA Excellence awards in Dubai. In 2016, while on holiday in Dubai, Athif Sarwar, came across the franchise and was later granted development rights to the franchise in the UK. Sarwar later purchased the international rights to the brand from Farshad Abbaszadeh, CEO and Founder of German Doner Kebab. The chain was then bought by the Sarwar Family in 2017, which moved its headquarters to Glasgow, Scotland, in the United Kingdom. In July 2022, Imran Sayeed, chief executive, expressed his desire for the company to be made public and listed on the New York Stock Exchange in the following three to five years, as the chain sees North America as its "next growth engine". In March 2023, Simon Wallis was appointed chief executive replacing Imran Sayeed, with Robin Caley as chief development officer.
A less common pathway for transmetalation is through a dissociative or solvent assisted mechanism. Here, a ligand from the tetravalent palladium species dissociates, and a coordinating solvent can add onto the palladium. When the solvent detaches, to form a 14-electron trivalent intermediate, the organostannane can add to the palladium, undergoing an open or cyclic type process as above.
HA (aq) + H2O (l) ⇌ H3O+ (aq) + A− (aq) Ka Common examples of monoprotic acids in mineral acids include hydrochloric acid (HCl) and nitric acid (HNO3). On the other hand, for organic acids the term mainly indicates the presence of one carboxylic acid group and sometimes these acids are known as monocarboxylic acid. Examples in organic acids include formic acid (HCOOH), acetic acid (CH3COOH) and benzoic acid (C6H5COOH). Polyprotic acids, also known as polybasic acids, are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic (or dibasic) acid (two potential protons to donate), and triprotic (or tribasic) acid (three potential protons to donate). Some macromolecules such as proteins and nucleic acids can have a very large number of acidic protons. A diprotic acid (here symbolized by H2A) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, Ka1 and Ka2.
Nickel-56, also doubly magic, is produced in large quantities in supernovae. In the last phases of stellar evolution of very large stars, fusion of lighter elements like hydrogen and helium comes to an end. Later in the star's life cycle, elements including magnesium, silicon, and sulfur are fused to form heavier elements. Once the last nuclear fusion reactions cease, the star collapses to produce a supernova. During the supernova, silicon burning produces 56Ni. This isotope of nickel is favored because it has an equal number of neutrons and protons, making it readily produced by fusing two 28Si atoms. 56Ni is the last element that can be formed in the alpha process. Past 56Ni, nuclear reactions are endoergic and energetically unfavorable. 56Ni decays to 56Co and then 56Fe by β+ decay. The radioactive decay of 56Ni and 56Co supplies much of the energy for the light curves observed for stellar supernovae. The shape of the light curve of these supernovae display characteristic timescales corresponding to the decay of 56Ni to 56Co and then to 56Fe.
=== Transdermal === There are several methods for transdermal delivery of insulin. Pulsatile insulin uses microjets to pulse insulin into the person, mimicking the physiological secretions of insulin by the pancreas. Jet injection had different insulin delivery peaks and durations as compared to needle injection. Some diabetics may prefer jet injectors to hypodermic injection. Both electricity using iontophoresis and ultrasound have been found to make the skin temporarily porous. The insulin administration aspect remains experimental, but the blood glucose test aspect of "wrist appliances" is commercially available Researchers have produced a watch-like device that tests for blood glucose levels through the skin and administers corrective doses of insulin through pores in the skin. A similar device, but relying on skin-penetrating "microneedles", was in the animal testing stage in 2015. In the last couple of years, the use of chemical enhancers, electrical devices, and microneedle devices has shown tremendous promise for improving the penetration of insulin compared to passive transport via the skin. Transdermal insulin delivery shows a more patient-friendly and minimally invasive approach to daily diabetes care than the conventional hypodermic injection however, additional research is necessary to address issues such as long-term use, delivery efficiency, and reliability, as well as side effects involving inflammation and irritation.
Sources: en.wikipedia.org
The genetic code translates mRNA nucleotide sequences to amino acid sequences. Genetic information is coded using this process with groups of three nucleotides along the mRNA which are commonly known as codons. The set of three nucleotides almost always produce the same amino acid with a few exceptions like UGA which typically serves as the stop codon but can also encode tryptophan in mammalian mitochondria. Most amino acids are specified by multiple codons demonstrating that the genetic code is degenerate–different codons result in the same amino acid. Codons that code for the same amino acid are termed synonyms. Silent mutations are base substitutions that result in no change of the amino acid or amino acid functionality when the altered messenger RNA (mRNA) is translated. For example, if the codon AAA is altered to become AAG, the same amino acid – lysine – will be incorporated into the peptide chain. Mutations are often linked to diseases or negative impacts but silent mutations can be extremely beneficial in creating genetic diversity among species in a population. Germ-line mutations are passed from the parent to the offspring. Scientists have predicted that people have approximately 5 to 10 deadly mutations in their genomes but this is essentially harmless because there is usually only one copy of a particular bad gene so diseases are unlikely. Silent mutations can also be produced by insertions or deletions, which cause a shift in the reading frame.
== History == Marc Wilkins coined the term proteome in 1994 in a symposium on "2D Electrophoresis: from protein maps to genomes" held in Siena in Italy. It appeared in print in 1995, with the publication of part of his PhD thesis. Wilkins used the term to describe the entire complement of proteins expressed by a genome, cell, tissue or organism.
Paul Joseph Kaesberg (September 26, 1923 – December 24, 2010) was a German-born American biochemist and virologist who was known worldwide for his extensive research regarding small viruses. His research significantly contributed to the our overall understanding of viruses today. Kaesberg is also known for discovering icosahedral-shaped viruses and for using X-rays to study viruses.
Beverly Gail Allitt (born 4 October 1968) is an English serial killer who was convicted of murdering three infants and an 11-year-old boy, attempting to murder three others, and causing grievous bodily harm to six more at Grantham and Kesteven Hospital, Lincolnshire, between February and April 1991. She committed the murders as a state enrolled nurse on the hospital's children's ward. Allitt administered large doses of insulin to at least two of her victims and a large air bubble was found in the body of another, but police were initially unable to establish how all of the attacks were carried out. In May 1993, Allitt received 13 life sentences at Nottingham Crown Court. The sentencing judge, Mr Justice David Latham, told Allitt that she was "a serious danger" to others and was unlikely ever to be considered safe enough to be released. Allitt is currently detained at Rampton Secure Hospital in Nottinghamshire. She became eligible for release on parole after her minimum tariff of 30 years' imprisonment expired in November 2021.
==== Increasing endogenous production ==== Regular exercise is known to increase DHEA production in the body. Calorie restriction has also been shown to increase DHEA in primates. Some theorize that the increase in endogenous DHEA brought about by calorie restriction is partially responsible for the longer life expectancy known to be associated with calorie restriction.
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.
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.