If you have been reading about reverse-phase HPLC 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 2026-07-11. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
| 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 |
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.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
== Screening and diagnosis == Screening for VRE can be done in several ways. For inoculating peri-rectal/anal swabs or stool specimens directly, one method uses bile esculin azide agar plates containing 6 μg/ml of vancomycin. Black colonies should be identified as an enterococcus to species level and further confirmed as vancomycin resistant by an MIC method before reporting as VRE. Vancomycin resistance can be determined for enterococcal colonies available in pure culture by inoculating a suspension of the organism onto a commercially available brain heart infusion agar (BHIA) plate containing 6 μg/ml vancomycin. The Clinical and Laboratory Standards Institute (CLSI) recommends performing a vancomycin MIC test and also motility and pigment production tests to distinguish species with acquired resistance (vanA and vanB) from those with vanC intrinsic resistance. Detection of vancomycin resistance by the use of PCR targeting vanA and vanB can also be performed. Once the individual has VRE, it is important to ascertain which strain.
=== mzPeak === Due to the increasing size of mass spectrometry raw-data files, the XML-backed mzML specification does not perform well enough with compressed data. The mzPeak format solves that by saving multiple files in an uncompressed zip file, with the raw data stored in parquet files for fast random access. The structure of the format is heavily inspired by mzML. Its specification is under development, as of September 2026, by HUPO-PSI and interested parties.
=== Pharmacokinetics === Due to the presence of its C17α methyl group, methylestradiol cannot be deactivated by oxidation of the C17β hydroxyl group, resulting in improved metabolic stability and potency relative to estradiol. This is analogous to the case of ethinylestradiol and its C17α ethynyl group.
Lori stated that he would be taking a sabbatical from the program until he recovers. She blamed the stroke on Bakker's hard work on his show and wrote that he had described the criticism against him as "the most vicious attack that he has ever experienced". Bakker returned to his program for the first time following his stroke on July 8, 2020. On June 23, 2021, Missouri Attorney General Eric Schmitt announced the settlement of the state's lawsuit against Bakker. Bakker and Morningside Church would be prohibited from saying silver solution could "diagnose, prevent, mitigate, treat, or cure any disease or illness". Restitution of about $157,000 would also be paid to those who bought silver solution between February 12, 2020, and March 10, 2020.
If it is important to have a uniform distribution of incubation times for the droplets, the delay line channel may contain regularly spaced constrictions. Droplets flowing through a channel of uniform diameter travel at different speeds based on their radial position; droplets closer to the center of the channel move faster than those near the edges. By narrowing the channel width to a fraction of its original size, droplets with higher velocities are forced to equilibrate with slower-moving droplets because the constriction allows fewer droplets to pass through at a time. Another manipulation to the geometry of the delay line channel involves introducing turns to the droplets' trajectory. This increases the extent to which any reagents contained within the droplets are mixed via chaotic advection. For systems requiring the incubation of 100 to 1000 droplets, traps can be fabricated in the delay line channel that store droplets separately from one another. This provides for finer control and monitoring of individual droplets.
Sources: en.wikipedia.org
The mechanism of action of pantoprazole is to inhibit the final step in gastric acid production. In the gastric parietal cell of the stomach, pantoprazole covalently binds to the H+/K+ ATP pump to inhibit gastric acid and basal acid secretion. The covalent binding prevents acid secretion for up to 24 hours and longer. Pantoprazole is metabolized in the liver by the cytochrome P450 system. Metabolism mainly consists of demethylation by CYP2C19 followed by sulfation. Another metabolic pathway is oxidation by CYP3A4. Pantoprazole metabolites are not thought to have any pharmacological significance. It is usually given with a prokinetic drug because of inactivity in the acidic environment of the stomach. Pantoprazole binds irreversibly to H+K+ATPase (proton pumps) to suppress the secretion of acid. Due to irreversible binding of the pumps, new pumps have to be made before acid production can be resumed. The drug's plasma half-life is about two hours. After administration, the time for the drug to reach peak plasma concentrations is 2 to 3 hours. The percentage of the drug that is protein bound is 98%.
Nor are rights of pre-emption to buy shares, nor rights of any party regarding claims by tort, contract or piercing the corporate veil to hold directors and shareholders accountable. However, Directives do require minimum rights on company formation, capital maintenance, accounting and audit, market regulation, board neutrality in a takeover bid, rules on mergers, and management of cross-border insolvency. The omission of minimum standards is important since the Court of Justice held in Centros that freedom of establishment requires companies operate in any member state they choose. This has been argued to risk a "race to the bottom" in standards, although the Court of Justice soon affirmed in Inspire Art that companies must still comply with proportionate requirements that are in the "public interest".
== Biosynthesis == (Z)-9-Tricosene is biosynthesized in house flies from nervonic acid. The acid is converted into the acyl-CoA derivative and then reduced to the aldehyde (Z)-15-tetracosenal. Through a decarboxylation reaction, the aldehyde is converted to (Z)-9-tricosene. The process is mediated by a cytochrome P450 enzyme and requires oxygen (O2) and nicotinamide adenine dinucleotide phosphate (NADPH).
For services to Paediatrics and to the Royal College of Paediatrics and Child Health. Graeme David William Odgers, Chairman, Monopolies and Mergers Commission. For services to Industry. Herman George Ouseley, Chairman, Commission for Racial Equality. For services to Community Relations and Local Government. John Michael Pickard, Chairman, London Docklands Development Corporation. For services to Urban Regeneration. Brian Mansel Richards, , Executive Chairman, Peptide Therapeutics Ltd. For services to the Biotechnology Industry. John David Rowland, Chairman, Lloyd's of London. For services to the Insurance Industry. Cyril David Townsend, , Member of Parliament for Bexleyheath. For political service. Professor Guenter Heinz Treitel, , lately Vinerian Professor of English Law, University of Oxford. For services to Law. The Honourable Miles Rawstron Walker, , lately Chief Minister, Isle of Man Government. For services to the Government of the Isle of Man. Ronald Matthew Watson, , Leader, Conservative Group, Association of Metropolitan Authorities. For services to Local Government. William Henry Weston Wells, Regional Chairman, South Thames NHS Executive. For services to Health Care. Raymond William Whitney, , Member of Parliament for Wycombe. For political service. John Basil Zochonis, . For political and public service.
== Medical significance == High levels of glucagon secretion has been implicated in both Type I and Type II diabetes. In fact, high levels of plasma glucagon is considered an early sign of the development of both Type I and Type II diabetes.
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 with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, designed as a metabolically stabilized analogue of the endogenous tetrapeptide tuftsin. It has been studied mainly against anxiety-related and cognitive endpoints rather than as an approved medicine in most jurisdictions.