Heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2025-12-15. Anything still debated is marked as such rather than presented as settled.
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.
Development work on the compound began in the 1980s and 1990s at the Institute of Molecular Genetics in Moscow, within the same research programme that produced the peptide Semax. Early investigators sought a tuftsin derivative with improved resistance to enzymatic breakdown and with activity in the central nervous system after peripheral administration. Most of the primary literature from this period was published in Russian, a factor that still shapes how easily the findings can be checked by outside groups.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
Clinical evidence comes mainly from small studies conducted in Russia, several of which were open-label or lacked robust blinding. Reported outcomes include lower anxiety scores, changes in attention measures, and effects on asthenic states following illness. Sample sizes are typically in the tens of participants, and independent replication outside the region is scarce. Reviews published in English generally note the limited methodological quality of the underlying trials. Whether the compound produces clinically meaningful effects under rigorous conditions remains unresolved.
Proposed mechanisms center on modulation of the GABA system, but no single molecular target has been confirmed. Rodent studies report changes in GABA-A receptor expression and in the turnover of serotonin, dopamine, and norepinephrine in several brain regions. Increases in brain-derived neurotrophic factor and its receptor have also been described after repeated administration. These findings come largely from animal models, and the degree to which they describe human neurochemistry remains an open question. The mechanism is best characterized as multi-system and not fully resolved.
extensive property A physical quantity whose value is proportional to the size of the system it describes or to the quantity of matter in the system. Examples include mass, volume, enthalpy, and entropy. Contrast intensive property.
=== Antibody Drug Conjugates === Antibody drug conjugates (ADCs) are composed of an antibody linked to a drug. Sortase can be used as a method to link these two molecules. Due to the site-specific ligation of sortase, it shows promise in being used as a method to create ADCs. Sortase poses a potential solution to the challenge of creating homogeneous ADCs where the drug is attached to a single specific site. A study showed that sortase derived ADCs can effectively kill tumors both in vitro and in vivo. Using sortase to manufacture ADCs may be able to simplify the production and reduce materials needed for the process. A challenge with using sortase for ADC preparation is the poor reaction kinetics of the natural enzyme. Using error prone PCR to generate mutants of SrtA, the most commonly used natural sortase variant, has been successful in generating more efficient sortase variants.
In the 1970s, a group of Chicana women brought up a federal class action lawsuit against a hospital in Los Angeles County regarding their sterilizations. Women in the class were allegedly given false information regarding sterilization. The titular plaintiff, Dolores Madrigal, a Latina woman, was allegedly told several times by a medical professional that sterilization could be reversed. Other women involved in the case signed consent forms for their sterilizations because they were allegedly sedated or manipulated by doctors and medical staff. A common reason for forcing the sterilizations of these women was apparently the burden that their future children would be to "taxpayers". Many of the women did not discover that they had been sterilized until they visited a doctor. The judge deciding Madrigal held that it was a part of a doctor's practice to provide sterilizations to these women based upon their cultural backgrounds. The judge, Judge Curtis, stated in his ruling that miscommunication between the doctors and the women, rather than malice, resulted in the sterilizations. In the words of his final comment, the judge stated, "One can sympathize with them for their inability to communicate clearly, but one can hardly blame the doctors for relying on these indicia of consent which appeared to be unequivocal on their face and which are in constant use in the medical center."
=== Pharmacodynamics === Compared to concentration dependent bactericidal antibiotics like aminoglycosides and fluoroquinolones, the antibacterial activity of β-lactam antibiotics are generally more time dependent. Unlike the former, when piperacillin-tazobactam concentrations exceed minimum inhibitory concentrations (MIC) of a pathogen by five folds, the exponential relationship between concentration and activity begins to level off. Otherwise, piperacillin-tazobactam bactericidal efficacy is shown to consist of a strong association with the duration of time the concentration exceeds minimum inhibitory concentrations (T>MIC). When the T>MIC in the serum equates to 60–70% of the frequency for drug administration (dosing interval), maximal activity is achieved against Gram-negative bacteria, while for Gram-positive bacteria it occurs at around 40–50%. Within a 24-hour period in one clinical study, a T>MIC surpassing 60% was found for piperacillin-susceptible bacteria including Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus in two dosing regimes (4.5 g every 8 hours and 3.375 g every 8 hours). The evidence for this was obtained through Monte Carlo experiments procured by a special program (OPTAMA), where for several different scenarios (e.g. hospital acquired infections, secondary peritonitis, skin or soft tissue infections), the probability of attaining those figures were in the ranges of 85–95% and 90–89% respectively for the two regimes.
Sources: en.wikipedia.org
== History == Pantoprazole was discovered by scientists at Byk Gulden, a subsidiary of Altana; the drug discovery program started in 1980, producing pantoprazole in 1985. The compound was actually created by chemists working to scale up a different chemical that had been chosen as a development candidate. Byk Gulden partnered with Smith Kline & French in 1984. The compound's development names were BY1029 and SK&F96022. By 1986 the companies had created the sodium salt, pantoprazole sodium sesquihydrate, and decided to develop it as it was more soluble and stable, and was more compatible with other ingredients used in the formulation. It was first marketed in Germany in 1994. Wyeth licensed the US patent from Altana, and obtained marketing approval from the US FDA in 2000 under the trade name Protonix. In 2004, worldwide sales of the drug were $3.65 billion, about half of which were in the US. In 2007, Altana's drug business was acquired by Nycomed. Nycomed was in turn acquired by Takeda in 2011 and Wyeth was acquired by Pfizer in 2009. The patent protecting the drug was set to expire in 2010, but Teva Pharmaceuticals filed an Abbreviated New Drug Application (ANDA) in 2007, and Wyeth and Nycomed sued Teva for patent infringement, but Teva decided to launch its generic drug "at risk" that year, before the patent had been invalidated. Wyeth launched an authorized generic in 2008. Pfizer and Takeda's patent exclusivity expired in 2010, and an administrative exclusivity they had for pediatric use expired in January 2011, and full generic competition began.
By that time, internal political life in Serbia was fully dominated by the Communist Party of Serbia, formed in May 1945 as a branch of the ruling Communist Party of Yugoslavia. In order to suppress remaining monarchist opposition, communists initiated the creation of a wider political coalition, thus establishing the People's Front of Yugoslavia (PFY), in August 1945. Other political parties were soon dissolved, and remnants of political life were constrained within the PFY, that was under full control of the ruling Communist Party.
PaTx1 is 83.3% identical to PATx2, differing only by two acidic residues(Chagot 2004)(Diochot 1999). Phrixotoxin-1 and -2 are similar to heteropodatoxin, which also has a blocking activity on Kv4.2 channels (Chagot 2004). Phrixotoxin-1, -2 and -3 contain an Inhibitor Cystine Knot (ICK) motif, and thus belong to the ICK peptide family(Chagot 2004)(Bosmans 2006).
== Chemerin-derived peptides == A particular synthetic chemerin-derived peptide, termed C15, was developed at Oxford University. It showed anti-inflammatory activities. Intraperitoneal administration of C15 (0.32 ng/kg) to mice before zymosan challenge conferred significant protection against zymosan-induced peritonitis, suppressing neutrophil (63%) and monocyte (62%) recruitment with a concomitant reduction in proinflammatory mediator expression. C15 was found to promote phagocytosis and efferocytosis in peritoneal macrophages at picomolar concentrations. C15 enhanced macrophage clearance of microbial particles and apoptotic cells by factor of 360% in vitro. Another chemerin-derived peptide, termed C-20, was developed at the Shenzhen Institute of Advanced Technology. Administration C-20 uncovered its high affinity binding to chemerin receptors CMKLR1 and GPR1, mimicking chemerin’s activity but with lower potency. C-20 triggered receptor internalization, promoted chemotaxis, and mildly suppressed hormone production (testosterone and progesterone), suggesting its potential as a tool to study chemerin-related signaling pathways.
== In popular culture == In the book Ozempic, la révolution de l'obésité ̶L’enquête, entitled A race for patents and Nobel Prizes, author Fabrice Delaye dedicates the third chapter to Mojsov. Delaye summarizes: “In 1982, the identification in animals of the slimming molecule GLP-1 triggered a fierce competition between Danish and American researchers to find it in humans.” It was in large part thanks to Mojsov’s critical contribution - she was the first to identify and synthesize the correct molecule - that the American team succeeded first. The second chapter of Off the Scales: The Inside Story of Ozempic and the Race to Cure Obesity by Aimee Donnellan focuses on Svetlana Mojsov’s fundamental contribution to the discovery of GLP-1. It also details her experience with her collaborators at Massachusetts General Hospital in Boston and the challenges she has faced to be acknowledged and included in the patents.
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, commonly written as TKPRPGP. It shares the first four residues with tuftsin and carries three prolines in the chain. The proline-rich tail is the main structural feature that separates it from the parent tetrapeptide.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
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.