tuftsin 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.
Last reviewed on 2025-11-06. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 |
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.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
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.
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.
=== Structure-activity experiments === When the 12-amino acid sequence of 'peptide 3'/CCL2 is aligned with the sequences of the other chemokines CCL3, CXCL8 and CXCL12 5 amino acids are conserved, Cys3, Asp5, Pro6, Trp10 and Gln12. In addition Val11 is also present in CCL3 and CXCL8. The corresponding 11th amino acid in CXCL12 is Ile. Ala4 in CCL2 is also present in CCL3 but the corresponding residue is Leu in CXCL8 and Ile in CXCL12. Inclusion of Leu at position 4 and Ile at position 11 (NH2-EICLDPKQKWIQ-OH) increased the inhibition potency of the peptide to 2-4μM. Removal of the first two residues from 'Peptide 3' (NH2-CADPKQKWVQ-OH) does not lower its BSCI potency. Peptide 3-Leu4, Ile11, the most potent BSCI peptide was chosen for further development. The first two amino acids were removed, and then according to the method of Jameson et al., the amino acid sequence was reversed and the amino acids replaced with D-amino acids. This combined transformation changes the orientation of the amides in the backbone but does not change the position of the amino acid sidechains. The peptide was then cyclised by adding a cysteine to the other end (HO-CLDPKQKWIQC-NH2), and oxidisation to form a disulfide bond to give NR58,3-14-3.
Le Cerveau by Gérard Oury (1968) La Beuze (2003) Disco (2008) La Fée, also presented at the Directors' Fortnight in 2011. The film by Sophie Marceau, La Disparue de Deauville, made in 2007, contains many scenes around the port of Le Havre, in the Coty shopping centre of Coty and in the streets of the central city. The film Le Havre by Aki Kaurismäki received two prizes at the 2011 Cannes Film Festival and also the Louis Delluc Prize. It was nominated three times for the 37th César Awards.
=== Therapeutic reactivation and gene therapy === While increasing p53 levels might appear beneficial for treating cancer, sustained p53 activation can cause premature aging. A more promising approach involves restoring normal, endogenous p53 function. In some tumor types, this leads to regression via apoptosis or normalization of cell growth. The first commercial gene therapy, Gendicine, was approved in China in 2003 for head and neck squamous cell carcinoma. It delivers a functional copy of the TP53 gene using a modified adenovirus. The small-molecule inhibitor MI-63 can bind to MDM2, blocking its interaction with p53 and reactivating p53 in cancers where its function is suppressed. A p53 reactivator rezatapopt is in clinical trials in patients whose tumors show the common Y220C mutation of p53, and restores anti-cancer effectiveness to the mutated protein.
Sources: en.wikipedia.org
Reef-building corals are well-studied holobionts that include the coral itself together with its symbiont zooxanthellae (photosynthetic dinoflagellates), as well as its associated bacteria and viruses. Co-evolutionary patterns exist for coral microbial communities and coral phylogeny. It is known that the coral's microbiome and symbiont influence host health, however, the historic influence of each member on others is not well understood. Scleractinian corals have been diversifying for longer than many other symbiotic systems, and their microbiomes are known to be partially species-specific. It has been suggested that Endozoicomonas, a commonly highly abundant bacterium in corals, has exhibited codiversification with its host. This hints at an intricate set of relationships between the members of the coral holobiont that have been developing as evolution of these members occurs. A study published in 2018 revealed evidence of phylosymbiosis between corals and their tissue and skeleton microbiomes. The coral skeleton, which represents the most diverse of the three coral microbiomes, showed the strongest evidence of phylosymbiosis. Coral microbiome composition and richness were found to reflect coral phylogeny. For example, interactions between bacterial and eukaryotic coral phylogeny influence the abundance of Endozoicomonas, a highly abundant bacterium in the coral holobiont. However, host-microbial cophylogeny appears to influence only a subset of coral-associated bacteria.
First, 2-chloro-6-methoxy-3-nitropyridine and 2-aminopropane-1,3-diol undergo nucleophilic aromatic substitution (SNAr) to form a diol, which is then protected by 2,2-dimethoxypropane to form a ketal intermediate. The intermediate is reduced with hydrogen catalyzed by Pd/C to afford an amine, which then immediately goes through substitution with ethyl bromoacetate. The resulting compound is treated with NaH, and is then oxidized with MnO2 to form the pyrazinone ring. The ketal is deprotected with aqueous HCl to regenerate the diol, and is then treated with methanesulfonic anhydride and triethylamine to form the final ring of the tricyclic core. The resulting compound goes through substitution with tert-butyl piperidin-4-ylcarbamate, acidic deprotection of the amino group, and chiral preparative HPLC to give the enantio-pure penultimate amine intermediate. Finally, a reductive amination is performed, and the product is treated with HCl in diethyl ether to form gepotidacin as a hydrochloride. This route consists of 11 steps, with 8 steps aimed at the formation of the tricyclic core.
=== Linear copolymers === Due to the wide variety of copolymers possible, there is no single accepted naming convention, but IUPAC has a general suggested naming scheme that indicates the organization of repeat units within a copolymers. In this convention, source based nomenclature is used to indicate the monomers from which the copolymer was synthesized. Following the IUPAC naming conventions, a generally copolymer is named poly(A-co-B), where A and B are the monomers and -co- represents the type of copolymer. This linkers changes with the type of copolymers, examples of which are shown below. If the exact structure of the polymer is unknown, the linker -co- should be used.
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.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.