If you have been reading about Tuftsin analogue 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.
Updated 2026-04-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | -20 °C or below | For lyophilized powder, long term |
| Common analytical method | Reverse-phase HPLC | Usually paired with mass spectrometry |
| Typical reported purity | At or above 95 percent by area | Research-grade material |
| Aqueous solubility | High | Solutions used in laboratory assays |
| Moisture sensitivity | Hydrolyzes in solution | Aseptic handling reduces degradation |
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 primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Reversed-phase high-performance liquid chromatography is the standard technique for estimating peptide purity. The result is a peak-area percentage, which describes how much of the detected material elutes as the main peak in one run. Mass spectrometry confirms the molecular mass and can reveal truncated, adducted, or otherwise modified species. Amino acid analysis or tandem mass spectrometry can address sequence fidelity when identity is in doubt. None of these measurements, taken alone, establishes that a sample is fit for any specific purpose.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
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.
=== Ligase concentration === As is usual for an enzyme, the higher the ligase concentration, the faster is the rate of ligation. Blunt-end ligation is much less efficient than sticky end ligation, so a higher concentration of ligase is used in blunt-end ligations. High DNA ligase concentration may be used in conjunction with PEG for a faster ligation, and they are the components often found in commercial kits designed for rapid ligation.
=== Light scattering === Static light scattering measures the product of weight-averaged molar mass and concentration of macromolecules in solution. Given a fixed total concentration of one or more species over the measurement time, the scattering signal is a direct measure of the weight-averaged molar mass of the solution, which will vary as complexes form or dissociate. Hence the measurement quantifies the stoichiometry of the complexes as well as kinetics. Light scattering assays of protein kinetics is a very general technique that does not require an enzyme.
=== Elderly === An increasing trend of anorexia among the elderly, termed "Anorexia of Aging", is observed, characterized by behaviors similar to those seen in typical anorexia nervosa but often accompanied by excessive laxative use. Most geriatric anorexia patients limit their food intake to dairy or grains, whereas an adolescent anorexic has a more general limitation. This eating disorder that affects older adults has two types – early onset and late onset. Early onset refers to a recurrence of anorexia in late life in an individual who experienced the disease during their youth. Late onset describes instances where the eating disorder begins for the first time late in life. The stimulus for anorexia in elderly patients is typically a loss of control over their lives, which can be brought on by many events, including moving into an assisted living facility. This is also a time when most older individuals experience a rise in conflict with family members, such as limitations on driving or limitations on personal freedom, which increases the likelihood of an issue with anorexia. There can be physical issues in the elderly that leads to anorexia of aging, including a decline in chewing ability, a decline in taste and smell, and a decrease in appetite. Psychological reasons for the elderly to develop anorexia can include depression and bereavement, and even an indirect attempt at suicide.
==== Social issues ==== Larson has consistently voted both to legalize same-sex marriage and to expand options for legal abortion. He voted to repeal the military's "don't ask, don't tell" policy, and in favor of the Sexual Orientation Employment Nondiscrimination Act (ENDA). The Human Rights Campaign gave Larson a rating of 94%. Larson voted against ending federal funding to Planned Parenthood; consequently, both Planned Parenthood and NARAL Pro-Choice American gave him a rating of 100%.
==== 3.A. P-P-bond hydrolysis-driven transporters ==== 3.A.1 ABC transporters including BtuCD, molybdate uptake transporter, Cystic fibrosis transmembrane conductance regulator and others 3.A.2 The H+- or Na+-translocating F-type ATPase, V-type ATPase and A-type ATPase superfamily 3.A.3 The P-type ATPase Superfamily 3.A.4 The Arsenite-Antimonite efflux family 3.A.5 General secretory pathway (Sec) translocon (preprotein translocase SecY) 3.A.6 The Type III (Virulence-related) Secretory Pathway (IIISP) Family 3.A.7 The Type IV (Conjugal DNA-Protein Transfer or VirB) Secretory Pathway (IVSP) Family 3.A.8 The Mitochondrial Protein Translocase (MPT) Family 3.A.9 The Chloroplast Envelope Protein Translocase (CEPT or Tic-Toc) Family 3.A.10 H+, Na+-translocating Pyrophosphatase family 3.A.11 The Bacterial Competence-related DNA Transformation Transporter (DNA-T) Family 3.A.12 The Septal DNA Translocator (S-DNA-T) Family 3.A.13 The Filamentous Phage Exporter (FPhE) Family 3.A.14 The Fimbrilin/Protein Exporter (FPE) Family 3.A.15 The Outer Membrane Protein Secreting Main Terminal Branch (MTB) Family 3.A.16 The Endoplasmic Reticular Retrotranslocon (ER-RT) Family 3.A.17 The Phage T7 Injectisome (T7 Injectisome) Family 3.A.18 The Nuclear mRNA Exporter (mRNA-E) Family 3.A.19 The TMS Recognition/Insertion Complex (TRC) Family 3.A.20 The Peroxisomal Protein Importer (PPI) Family 3.A.21 The C-terminal Tail-Anchored Membrane Protein Biogenesis/ Insertion Complex (TAMP-B) Family 3.A.22 The Transcription-coupled TREX/TAP Nuclear mRNA Export Complex (TREX) Family 3.A.23 The Type VI Symbiosis/Virulence Secretory Pathway (VISP) Family 3.A.24 Type VII or ESX Protein Secretion System (T7SS) Family 3.A.25 The Symbiont-specific ERAD-like Machinery (SELMA) Family 3.A.26 The Plasmodium Translocon of Exported proteins (PTEX) Family
Sources: en.wikipedia.org
The next few years saw the seeming recovery of Austria's position on the international scene following the near disasters of 1848–1849. Under Schwarzenberg's guidance, Austria was able to stymie Prussian scheming to create a new German Federation under Prussian leadership, excluding Austria. After Schwarzenberg's premature death in 1852, he could not be replaced by statesmen of equal stature, and the emperor himself effectively took over as prime minister. He established absolutist rule by issuing the March Constitution (Austria) in 1849. This was in turn revoked by the Silvesterpatent. Seeking to borrow money on foreign markets, he relented and issued the February Patent in 1861 which established the Empire's constitution. He was one of the most prominent Roman Catholic rulers in Europe, and a fierce enemy of Freemasonry.
=== Mantle minerals === Ferropericlase (Mg,Fe)O, a solid solution of periclase (MgO) and wüstite (FeO), makes up about 20% of the volume of the lower mantle of the Earth, which makes it the second most abundant mineral phase in that region after silicate perovskite (Mg,Fe)SiO3; it also is the major host for iron in the lower mantle. At the bottom of the transition zone of the mantle, the reaction γ-(Mg,Fe)2SiO4 ⇌ (Mg,Fe)SiO3 + (Mg,Fe)O transforms γ-olivine into a mixture of silicate perovskite and ferropericlase and vice versa. In the literature, this mineral phase of the lower mantle is also often called magnesiowüstite. Silicate perovskite may form up to 93% of the lower mantle, and the magnesium iron form, (Mg,Fe)SiO3, is considered to be the most abundant mineral in the Earth, making up 38% of its volume.
== Further reading == All the Birds of the World, Lynx Edicions, 2020. Del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.). Handbook of the Birds of the World (17-volume encyclopaedia), Lynx Edicions, Barcelona, 1992–2010. (Vol. 1: Ostrich to Ducks: ISBN 978-84-87334-10-8, etc.). Lederer, Roger; Carol Burr (2014). Latein für Vogelbeobachter: über 3000 ornithologische Begriffe erklärt und erforscht, aus dem Englischen übersetzt von Susanne Kuhlmannn-Krieg, Verlag DuMont, Köln, ISBN 978-3-8321-9491-8. National Geographic Field Guide to Birds of North America, National Geographic, 7th edition, 2017. ISBN 9781426218354 National Audubon Society Field Guide to North American Birds: Eastern Region, National Audubon Society, Knopf. National Audubon Society Field Guide to North American Birds: Western Region, National Audubon Society, Knopf. Svensson, Lars (2010). Birds of Europe, Princeton University Press, second edition. ISBN 9780691143927 Svensson, Lars (2010). Collins Bird Guide: The Most Complete Guide to the Birds of Britain and Europe, Collins, 2nd edition. ISBN 978-0007268146
The native tribes of East Malaysia have their own languages which are related to, but easily distinguishable from, Malay. Iban is the main tribal language in Sarawak while Dusunic and Kadazan languages are spoken by the natives in Sabah. Chinese Malaysians predominantly speak Chinese dialects from the southern part of China. The more common Chinese varieties in the country are Mandarin, Cantonese, Hokkien, and so on. The Tamil language is used predominantly by the majority of Malaysian Indians. A small number of Malaysians have European ancestry and speak creole languages, such as the Portuguese-based Malaccan Creoles, and the Spanish-based Chavacano language.
Hydrazones are a class of organic compounds with the structure R1R2C=N−NH2. They are related to ketones and aldehydes by the replacement of the oxygen =O with the =N−NH2 functional group. They are formed usually by the action of hydrazine on ketones or aldehydes.
Sources: en.wikipedia.org
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.
Lyophilized powder is usually kept frozen and protected from moisture. Solutions are less stable and are often used promptly or divided into aliquots to avoid repeated freeze-thaw cycles. Exact shelf-life values depend on purity and handling.
No. A purity figure derived from chromatographic area does not prove the amino acid sequence. Identity requires an orthogonal method such as mass spectrometry or sequencing. Truncated or isomerized peptides can co-elute with the target compound.
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.