heptapeptide is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2025-11-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Modeled on tuftsin |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues |
| Approximate molecular mass | Around 750 Da | Depends on counter-ion and hydration |
| Common forms | Lyophilized powder | Also described as aqueous solution |
| Primary origin of research | Russian laboratories | Mid-1990s onward |
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
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.
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.
== Mobile phase == The mobile phase, or the liquid phase that runs across the column during separation, for HILIC is typically composed of a high amount of water-miscible, polar organic solvent and a low amount of water. Typically, acetonitrile ("MeCN", also designated as "ACN") is used for the organic solvent, though other aprotic water-miscible solvents, such as alcohols at higher concentration, tetrahydrofuran, or dioxane, can also be used. As with other methods of chromatography, the mobile phase can be delivered isocratically or with a gradient starting at high-organic progressing towards increasing aqueous content. If using a mobile phase gradient, the mobile phase will progressively increases in polar-aqueous content, causing increasingly polar analytes to be eluted. All ions partition into the stationary phase to some degree, so an occasional "wash" with water is required to ensure a reproducible stationary phase.
=== PDCAAS === The earlier "modern" measurement is the PDCAAS of 1989. For protein digestibility it compares the amount of protein-nitrogen that goes into a rat and out of the rat through feces, with a correction for "metabolic fecal protein": the amount of protein that occurs in feces when the rat is on a protein-free diet. For the amino acid score, it considers the quantity of each essential amino acid in the food as a proportion of the food's protein content and compares this to nutritional recommendations for preschool-age kids. The amino acid score used is that of the lowest, or 'limiting', amino acid. The amino acid score is then multiplied with the fecal digestibility score to get an overall score between zero and one. The PDCAAS has a tendency to over-estimate digestibility, because it measures feces instead of what remains at the end of the small intestine, where most protein absorption is believed to occur. Antinutrient factors like phytic acid and trypsin inhibitors may decrease absorption of protein, as does the absorption of protein by gut bacteria in the test subject's large intestine. In addition, older rats show lower PDCAAS-estimated fecal digestibility compared to young rats when the protein source contains anti-nutritional factors.
This timeline lists notable events in the history of research into senescence or biological aging, including the research and development of life extension methods, brain aging delay methods and rejuvenation. People have long been interested in making their lives longer and healthier. The most ancient Egyptian, Indian and Chinese books contain reasoning about aging. Ancient Egyptians used garlic in large quantities to extend their lifespan. Hippocrates (c. 460 – c. 370 BCE), in his Aphorisms, and Aristotle (384–322 BCE), in On youth and old age, expressed their opinions about reasons for old age and gave advice about lifestyle. Medieval Persian physician Ibn Sina (c. 980 – 1037), known in the West as Avicenna, summarized the achievements of earlier generations about this issue.
Traditionally, homeless shelters ban alcohol. In 1997, as the result of an inquest into the deaths of two people experiencing homelessness who recreationally used alcohol two years earlier, Toronto's Seaton House became the first homeless shelter in Canada to operate a "wet shelter" on a "managed alcohol" principle in which clients are served a glass of wine once an hour unless staff determine that they are too inebriated to continue. Previously, people experiencing homelessness who consumed excessive amounts of alcohol opted to stay on the streets, often seeking alcohol from unsafe sources such as mouthwash, rubbing alcohol or industrial products which, in turn, resulted in frequent use of emergency medical facilities. The programme has been duplicated in other Canadian cities, and a study of Ottawa's "wet shelter" found that emergency room visit and police encounters by clients were cut by half. The study, published in the Canadian Medical Association Journal in 2006, found that serving people experiencing long-term homelessness and who consume excessive amounts of alcohol controlled doses of alcohol also reduced their overall alcohol consumption. Researchers found that programme participants cut their alcohol use from an average of 46 drinks a day when they entered the programme to an average of 8 drinks and that their visits to emergency rooms dropped from 13.5 to an average of 8 per month, while encounters with the police fall from 18.1 to an average of 8.8.
Sources: en.wikipedia.org
ion channel A type of transmembrane protein complex which forms an aqueous pore or channel spanning the lipid bilayer of a membrane, through which specific inorganic, electrically charged ions can diffuse down their electrochemical gradients.
When allowed to react with superacids, sulfuric acid can act as a base and can be protonated, forming the [H3SO4]+ ion. Salts of [H3SO4]+ have been prepared (e.g. trihydroxyoxosulfonium hexafluoroantimonate(V) [H3SO4]+[SbF6]−) using the following reaction in liquid HF:
In September 2015, it was announced that at least part of Buc-ee's corporate operations would move into office space in Pearland Town Center. The "partial headquarters" would house the company's legal and human resources departments. The space was ready by early 2016. The second Buc-ee's in the Dallas–Fort Worth metroplex, the 32nd location in Texas, opened on May 23, 2016. The store is in northern Fort Worth, across from Texas Motor Speedway. The third DFW location opened in Denton, Texas, on October 29, 2018. Buc-ee's established another store in Melissa, Texas, on February 5, 2018. The store is located off New Davis Road and U.S. Highway 75, and it opened on April 29, 2019.
===== Rpn13 ===== Rpn13 was identified as a ubiquitin receptor using a Yeast-2-hybrid screen. Ubiquitin binding to Rpn13 is through the pleckstrin-like receptor for the Ub (PRU) domain. and mutations to the PRU block binding to ubiquitin. Rpn13 binds the proteasome through Rpn2 and sits at the top of the 19S, positioned over the OB ring of the motor. Rpn13 also binds and activates a Deubiquitinating enzyme, UCH37 (see below).
=== Creatinine clearance CCr === One method of determining GFR from creatinine is to collect urine (usually for 24 h) to determine the amount of creatinine that was removed from the blood over a given time interval. If one removes 1440 mg in 24 h, this is equivalent to removing 1 mg/min. If the blood concentration is 0.01 mg/mL (1 mg/dL), then one can say that 100 mL/min of blood is being "cleared" of creatinine, since, to get 1 mg of creatinine, 100 mL of blood containing 0.01 mg/mL would need to have been cleared. Creatinine clearance (CCr) is calculated from the creatinine concentration in the collected urine sample (UCr), urine flow rate (Vdt), and the plasma concentration (PCr). Since the product of urine concentration and urine flow rate yields creatinine excretion rate, which is the rate of removal from the blood, creatinine clearance is calculated as removal rate per min (UCr×Vdt) divided by the plasma creatinine concentration. This is commonly represented mathematically as
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BASF announced that the transaction would allow the company to focus on its chemical and refinery catalysts business. Since 2016, BASF has partnered with a subsidiary of Xinjiang Zhongtai Group, a company sanctioned under the Uyghur Forced Labor Prevention Act, to operate a plant in Korla. In October 2017, BASF announced it would buy seed and herbicide businesses from Bayer for €5.9 billion ($7 billion), as part of Bayer's acquisition of Monsanto. The company announced the start of a US$10 billion investment project in the south-western Chinese city of Zhanjiang, in November 2019. The project was approved in 2022. This ″Verbund″ site is intended for the production of engineering plastics and TPU. The site would be the third-largest BASF site worldwide, following Ludwigshafen, Germany, and Antwerp, Belgium. The first plant started up in 2022, and the entire site is expected to be completed by 2030.
== Biochemical details == Methionine (abbreviated as Met or M; encoded by the codon AUG) is an α-amino acid that is used in the biosynthesis of proteins. It contains a carboxyl group (which is in the deprotonated −COO− form under biological pH conditions), an amino group (which is in the protonated −NH+3 form under biological pH conditions) located in α-position with respect to the carboxyl group, and an S-methyl thioether side chain, classifying it as a nonpolar, aliphatic amino acid. In nuclear genes of eukaryotes and in Archaea, methionine is coded for by the start codon, meaning it indicates the start of the coding region and is the first amino acid produced in a nascent polypeptide during mRNA translation.
mab: whole monoclonal antibody Fab: fragment, antigen-binding (one arm) F(ab')2: fragment, antigen-binding, including hinge region (both arms) Fab': fragment, antigen-binding, including hinge region (one arm) Variable fragments: scFv: single-chain variable fragment di-scFv: dimeric single-chain variable fragment sdAb: single-domain antibody BsAb: bispecific monoclonal antibody: 3funct: trifunctional antibody BiTE: bi-specific T-cell engager This list of over 500 monoclonal antibodies includes approved and investigational drugs as well as drugs that have been withdrawn from market; consequently, the column Use does not necessarily indicate clinical usage. See the list of FDA-approved therapeutic monoclonal antibodies in the monoclonal antibody therapy page.
with equality only for the equilateral triangle. If an inner triangle is inscribed in a reference triangle so that the inner triangle's vertices partition the perimeter of the reference triangle into equal length segments, the ratio of their areas is bounded by
small nucleolar RNA (snoRNA) A class of small non-coding RNA molecules whose primary function is to direct the post-transcriptional modification of other RNAs, mainly transfer RNAs (tRNA), small nuclear RNAs (snRNA), and especially ribosomal RNAs (rRNA) as a part of ribosome synthesis in the nucleolus. SnoRNAs contain antisense sequences that complement sequences within these target RNAs and guide ribonucleoprotein complexes to them, which can then catalyze specific nucleoside modifications, typically methylation or pseudouridylation.
Sources: en.wikipedia.org
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.
It originates from research in Russia, associated with the Institute of Molecular Genetics of the Russian Academy of Sciences. The first descriptions date to the mid-1990s. Most published studies come from Russian laboratories.
No, Selank itself does not occur naturally. Its backbone is based on tuftsin, which is produced in the body, but the seven-residue version is a synthetic construct. It is supplied as a manufactured peptide.
Intranasal administration predominates in both animal and human research because it avoids hepatic first-pass metabolism. Injectable and intraperitoneal routes appear in animal work mainly for comparison.