If you have been reading about Enkephalinase 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 2026-02-27. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Lyophilised material kept dry at minus 20 degrees Celsius or colder is the most stable form, and suppliers commonly state a shelf life of two years or more under those conditions. Once dissolved, degradation accelerates through hydrolysis and deamidation, particularly at alkaline pH or elevated temperature. Working solutions are usually divided into single-use aliquots to avoid repeated freeze-thaw cycles. The choice of reconstitution solvent affects both stability and the ionic strength of the final preparation.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
| 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 |
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.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
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.
== Plot == Agents of the terrorist organization HYDRA invade an S.H.I.E.L.D. facility, killing Clay Quartermain and reviving a cryogenically preserved Baron Wolfgang Von Strucker. Nick Fury, retired and living in an abandoned mine shaft in the Yukon, is approached by S.H.I.E.L.D. agents Alexander Pierce and Contessa Valentina Allegra De Fontaine to return to duty to take down Hydra, now led by the children of Von Strucker, an old enemy of his. Fury refuses to return until he learns of Quartermain's death. He then accompanies Pierce and De Fontaine to a S.H.I.E.L.D. Helicarrier, where he reunites with old friends Dum Dum Dugan and Gabriel Jones, is introduced to telepath Kate Neville, clashes with new S.H.I.E.L.D. Director General Jack Pincer is shown advanced technologies that S.H.I.E.L.D. is developing, including a Life Model Decoy of Fury. Shown a recording of Quartermain's death, with the killer taunting Fury by name, and informed that the killer was Von Strucker's daughter, codenamed Viper, Fury deduces that Von Strucker's body was taken to harvest a pathogen known as the Death's Head Virus, developed by Arnim Zola to be Hitler's doomsday weapon. Viper calls a meeting of the remaining four Hydra lieutenants from Cairo, Osaka, Prague, and London. She executes the London lieutenant for questioning her authority. Fury learns that Zola is still alive and being kept in a S.H.I.E.L.D. safehouse in Berlin, and Fury and De Fontaine travel there.
== Release of GST-A1 as an indication of cellular necrosis == Increases in serum and urinary GST-A1 have been found in association with hepatocyte and renal proximal tubular necrosis respectively, and have potential for monitoring injury to these tissues.
Lebrikizumab, sold under the brand name Ebglyss, is a humanized monoclonal antibody used for the treatment of atopic dermatitis (atopic eczema). It is an interleukin 13 antagonist. It is given by subcutaneous injection. The most common side effects include injection site reactions, dry eye and conjunctivitis, including allergic conjunctivitis. Lebrikizumab was approved for medical use in the European Union in November 2023, in Canada in June 2024, and in the US in September 2024.
=== Upgrades === Chain Home was the primary radar system of the UK for only a short time. By 1942, many of its duties had been taken over by the far more advanced AMES Type 7 ground-controlled interception (GCI) radar systems. Whereas CH scanned an area perhaps 100 degrees wide and required considerable effort to take measurements, the Type 7 scanned the entire 360-degree area around the station, and presented it on a plan position indicator, essentially a real-time two-dimensional map of the airspace around the station. Both fighters and bombers appeared on the display, and could be distinguished using Identification friend or foe (IFF) signals. The data from this display could be read directly to the intercepting pilots, without the need for additional operators or control centres. With the deployment of GCI, CH became the early warning portion of the radar network. To further simplify operations and reduce manpower requirements, the job of plotting the targets became semi-automated. An analogue computer of some complexity, known as "The Fruit Machine", was fed information directly from the operator console, reading the goniometer setting for bearing, and the range from the setting of a dial that moved a mechanical pointer along the screen until it lay over a selected target. When a button was pushed, the Fruit Machine read the inputs and calculated the X and Y location of the target, which a single operator could then plot on a map, or relay directly over the telephone.
German painters have influenced Western art. Albrecht Dürer, Hans Holbein the Younger, Matthias Grünewald and Lucas Cranach the Elder were important German artists of the Renaissance, Johann Baptist Zimmermann of the Baroque, Caspar David Friedrich and Carl Spitzweg of Romanticism, Max Liebermann of Impressionism and Max Ernst of Surrealism. Several German art groups formed in the 20th century; Die Brücke (The Bridge) and Der Blaue Reiter (The Blue Rider) influenced the development of expressionism in Munich and Berlin. The New Objectivity arose in response to expressionism during the Weimar Republic. After World War II, broad trends in German art include neo-expressionism and the New Leipzig School. German designers became early leaders of modern product design. The Berlin Fashion Week and the fashion trade fair Bread & Butter are held twice a year. Architectural contributions from Germany include the Carolingian and Ottonian styles, which were precursors of Romanesque. Brick Gothic is a distinctive medieval style that evolved in Germany. Also in Renaissance and Baroque art, regional and typically German elements evolved (e.g. Weser Renaissance). Vernacular architecture in Germany is often identified by its timber framing (Fachwerk) traditions and varies across regions, and among carpentry styles. When industrialisation spread across Europe, classicism and a distinctive style of historicism developed in Germany, sometimes referred to as Gründerzeit style. Expressionist architecture developed in the 1910s in Germany and influenced Art Deco and other modern styles.
Sources: en.wikipedia.org
Surgical technique – the septal mucosal flap The surgeon cuts the anteriorly based septal mucosal tissue-flap as widely as possible, and then releases it with a low, posterior back-cut; but only as required to allow the rotation of the tissue-flap into the nasal wound.
== Background == An estimated 50% of oxidoreductases catalyze the transfer of a hydride using the nicotinamide adenine dinucleotide cofactor NAD(P). Nicotinamide adenine dinucleotide phosphate (NADPH) is used in anabolic reactions while nicotinamide adenine dinucleotide (NAD) is used in catabolic reactions. In the field of biocatalysis, NAD(P)-dependent oxidoreductases are widely used for the production of chiral alcohols, amines, and other valuable compounds. Yet the reduced forms of the cofactor, NADH and NADPH, needed for the catalysis, is too expensive to be used in stoichiometric amounts. Therefore a cofactor recycling system is usually employed.
===== Excavata ===== Leishmania tarentolae (cannot infect mammals) expression systems allow stable and lasting production of proteins at high yield, in chemically defined media. Produced proteins exhibit fully eukaryotic post-translational modifications, including glycosylation and disulfide bond formation.
The press over the litigation and public concern over the claims of A2 Corporation led the New Zealand Food Safety Authority and the Ministry of Health and the Food Standards Australia New Zealand to issue statements confirming the safety of conventional milk. A2 Corporation was able to obtain agreements with enough dairy farmers to launch A1 protein-free milk under its a2 and a2 MILK brands in New Zealand at the end of April 2003. In the middle of 2003, both founders of the company died. In July, Paterson was found dead in his hotel room during a business trip at the age of 50, and a month later Dr Corran McLachlan died of cancer at the age of 59. In New Zealand it is illegal to make health claims about a food product without providing scientific evidence and registering the food as a medicine, and in November 2003 the New Zealand Commerce Commission advised that A2 Corporation Ltd and its licensed producers of A1 protein-free milk had agreed to amend the health claims in their promotional material following a warning from the commission. By end of 2003 the weakened A2 Corporation had withdrawn the litigation against Fonterra and negotiations had resumed. The company, which had been in a tenuous financial situation since beginning trading in May, went into administration in October and was liquidated in November, owing farmers and processors tens of thousands of dollars. A NZ$1.27 million federal government grant awarded to the company in August as part of the Regional Partnerships Program was also cancelled.
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.
Dry powder is best kept sealed, protected from light, and held at minus 20 degrees Celsius or below. Desiccant packaging helps limit moisture uptake because the material is hygroscopic. A sealed vial should be allowed to equilibrate to room temperature before opening to reduce condensation.