This is a working overview of Selank, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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 |
| 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 |
Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.
Identity and purity of selank are established with reversed-phase high-performance liquid chromatography coupled to mass spectrometry. The peptide elutes from C18 columns with acetonitrile gradients in water containing trifluoroacetic acid or formic acid, and detection is usually performed by ultraviolet absorbance near 214 nm. Electrospray ionization in positive mode gives a doubly protonated ion near m/z 377, consistent with a mass of about 752 Da. Amino acid analysis or tandem mass spectrometry of fragment ions confirms the sequence. Because the molecule has no aromatic residues, it lacks a usable 280 nm chromophore, so low-wavelength detection or mass spectrometry is required.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
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.
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.
The lanthanides and late actinides usually have high fourth ionisation energies and hence rarely surpass the +3 oxidation state, whereas early actinides have low fourth ionisation energies and so for example neptunium and plutonium can reach +7. The very last actinides go further than the lanthanides towards low oxidation states: mendelevium is more easily reduced to the +2 state than thulium or even europium (the lanthanide with the most stable +2 state, on account of its half-filled f-shell), and nobelium outright favours +2 over +3, in contrast to ytterbium. As elements in the same group share the same valence configurations, they usually exhibit similar chemical behaviour. For example, the alkali metals in the first group all have one valence electron, and form a very homogeneous class of elements: they are all soft and reactive metals. However, there are many factors involved, and groups can often be rather heterogeneous. For instance, hydrogen also has one valence electron and is in the same group as the alkali metals, but its chemical behaviour is quite different. The stable elements of group 14 comprise a nonmetal (carbon), two semiconductors (silicon and germanium), and two metals (tin and lead); they are nonetheless united by having four valence electrons. This often leads to similarities in maximum and minimum oxidation states (e.g. sulfur and selenium in group 16 both have maximum oxidation state +6, as in SO3 and SeO3, and minimum oxidation state −2, as in sulfides and selenides); but not always (e.g.
==== Case study ==== The Kennewick Man is a notable example of human remains caught in a struggle between scientific merit and cultural traditions. Since his discovery in 1996, his fate has been the topic of great controversy. As one of the oldest well-preserved ancient skeletons found in America, scientists are eager to conduct various testing on the remains. Native American groups, however, have been adamantly calling for his repatriation and reburial, as per their traditions.
== History == The glucose clamp technique was developed by University of Texas (UT) School of Medicine Professors DeFronzo, Andres and Tobin in 1979. It has since been the gold standard for pharmacodynamic studies in diabetes drug development and diagnostics evaluation. In human clinical trials, manual glucose clamps as well as the more modern method of automated glucose clamp find common use.
The Census and Statistics Department estimated Hong Kong's population at 7,413,070 in 2021. The overwhelming majority (91.6%) is Chinese, most of whom are Taishanese, Teochew, Hakka, and other Cantonese peoples. The remaining 8.4% are non-ethnic Chinese minorities, primarily Filipinos, Indonesians, and South Asians. However, most Filipinos and Indonesians in Hong Kong are short-term workers. According to a 2021 thematic report by the Hong Kong government, after excluding foreign domestic helpers, the real number of non-Chinese ethnic minorities in the city was 301,344, or 4% of Hong Kong's population. About half the population have some form of British nationality, a legacy of colonial rule; 3.4 million residents have British National (Overseas) status, and 260,000 British citizens live in the territory. The vast majority also hold Chinese nationality, automatically granted to all ethnic Chinese residents at the handover. Headline population density exceeds 7,060 people/km2 It is the fourth-highest in the world.
, yielding the formula for absorbance of a material discussed below. Even though this absorbance function is very useful with scattering samples, the function does not have the same desirable characteristics as it does for non-scattering samples. There is, however, a property called absorbing power which may be estimated for these samples. The absorbing power of a single unit thickness of material making up a scattering sample is the same as the absorbance of the same thickness of the material in the absence of scatter.
Sources: en.wikipedia.org
Other medications including beta-blockers, diuretics, phenothiazines, phenytoin, rifampin, anti-TNF therapy Burns Influenza Surgery Consumption of raw bok choy Diabetic ketoacidosis after total thyroidectomy
Furthermore, NASA gathered and published data indicating a significant heat signature at the military base, suggesting that a sizeable fire had erupted at the site overnight. In Kandahar, Pakistani officials released aerial footage of a large explosion at an ammunition depot near Kandahar International Airport (KDH). BBC News, using satellite imagery, confirmed the location of an ammunition depot in Kandahar. In Paktika, a video shared on social media showed smoke rising from a Taliban military base in the Urgun District. BBC News confirmed the location by matching roads and a distinctive foreground building with satellite imagery. Analysts at Maiar, an intelligence firm, stated that Pakistan's strikes on buildings and other infrastructure in Afghanistan appeared to be largely confined to military sites. They said that one of the buildings struck in Kabul appeared to be a military headquarters or command-and-control centre, and that vehicles parked nearby suggested the building had been occupied. In Kandahar, the analysts reported damage to at least two buildings within a large complex, which they assessed to be a headquarters of some kind. PAF airstrikes in Kandahar province also struck the former home of Mullah Omar, the late founder of the Taliban, which was currently serving as a base for the Taliban's suicide unit. The property is located about one kilometer from the residence of the current Taliban leader, Hibatullah Akhundzada. According to local Afghan sources, about 15 Taliban members were killed in the strike.
the sclerotome, which forms cartilage, the syndetome, which forms tendons, the myotome, which forms skeletal muscle, the dermatome, which forms the dermis as well as skeletal muscle, and endothelial cells.
A sarcomere is defined as the segment between two neighbouring Z-lines (or Z-discs). In electron micrographs of cross-striated muscle, the Z-line (from the German "zwischen" meaning between) appears in between the I-bands as a dark line that anchors the actin myofilaments. Surrounding the Z-line is the region of the I-band (for isotropic). I-band is the zone of thin filaments that is not superimposed by thick filaments (myosin). Following the I-band is the A-band (for anisotropic). Named for their properties under a polarized light microscope. An A-band contains the entire length of a single thick filament. The anisotropic band contains both thick and thin filaments. Within the A-band is a paler region called the H-zone (from the German "heller", brighter). Named for their lighter appearance under a polarization microscope. H-band is the zone of the thick filaments that has no actin. Within the H-zone is a thin M-line (from the German "mittel" meaning middle), appears in the middle of the sarcomere formed of cross-connecting elements of the cytoskeleton.
Starting in the late 1980s, under the rule of Mikhail Gorbachev, the Soviet government undertook a program of political reforms (glasnost and perestroika) intended to liberalise and revitalise the Union. These measures, however, had a number of unintended political and social effects. Political liberalisation allowed the governments of the union republics to openly express sentiments related to nationalism. In addition, the loosening of political restrictions led to fractures within the Communist Party which resulted in a reduced ability to govern the Union effectively. The rise of nationalist and right-wing movements, notably led by Boris Yeltsin in Russia, in the previously homogeneous political system undermined the Union's foundations. With the central role of the Communist Party removed from the constitution, the Party lost its control over the State machinery and was banned from operating after an attempted coup d'état. Throughout this period of turmoil, the Soviet government attempted to find a new structure that would reflect the increased authority of the republics. Some autonomous republics, like Tatarstan, Checheno-Ingushetia, Abkhazia, South Ossetia, Crimea, Transnistria, Gagauzia sought the union statute in the New Union Treaty. Efforts to found a New Union Treaty, however, proved unsuccessful and the republics began to secede from the Union. By 6 September 1991, the Soviet Union's State Council recognized the independence of Estonia, Latvia and Lithuania bringing the number of union republics down to 12.
Sources: en.wikipedia.org
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to form images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from computed tomography (CT) and positron emission tomography (PET) scans. MRI is a medical application of nuclear magnetic resonance (NMR) , which can also be used for imaging in other NMR applications, such as NMR spectroscopy. MRI is widely used in hospitals and clinics for medical diagnosis, staging and follow-up of disease. In the early 1970s, it was demonstrated by R. Damadian, C.F. Hazlewood and D.C. Chang that measurement of NMR relaxation times can be used to detect cancer. Soon after that, P.C. Lauterbur proposed to use a magnetic field gradient to generate the NMR image in a 2-D plane. Compared to CT, MRI provides better contrast in images of soft tissues, e.g. in the brain or abdomen. However, it may be perceived as less comfortable by patients, due to the usually longer and louder measurements with the subject in a long, confining tube, although "open" MRI designs mostly relieve this. Additionally, implants and other non-removable metal in the body can pose a risk and may exclude some patients from undergoing an MRI examination safely. MRI was originally called NMRI (nuclear magnetic resonance imaging), but "nuclear" was dropped to avoid negative associations.
Artificially created antimatter is usable only as an energy storage medium, not as an energy source, unless future technological developments (contrary to the conservation of the baryon number, such as a CP violation in favor of antimatter) allow the conversion of ordinary matter into anti-matter. Theoretically, humans may be able to cultivate and harvest a number of naturally occurring sources of antimatter in the future. Renewable energy by converting sunlight into electricity – either directly through solar cells and concentrating solar power, or indirectly through biofuels, wind, and hydroelectric power: There is no known way for a human civilization to harness the equivalent of the Earth's total absorbed solar energy without completely covering the surface with man-made structures, which is not feasible with current technology. However, if a civilization constructed very large space-based solar power satellites, Type I power levels might become achievable—these could convert sunlight to microwave power and beam it to collectors on Earth.
Accessory nail of the fifth toe Accessory tragus (ear tag, preauricular appendage, preauricular tag) Amniotic band syndrome (ADAM complex, amniotic band sequence, congenital constriction bands, pseudoainhum) Aplasia cutis congenita (cutis aplasia, congenital absence of skin, congenital scars) Arteriovenous fistula Benign neonatal hemangiomatosis Branchial cyst (branchial cleft cyst) Bronchogenic cyst Capillary hemangioma (infantile hemangioma, nevus maternus, strawberry hemangioma, strawberry nevus) Cavernous venous malformation Congenital cartilaginous rest of the neck (cervical accessory tragus, wattle) Congenital erosive and vesicular dermatosis Congenital hypertrophy of the lateral fold of the hallux Congenital lip pit (congenital sinus of the lower lip, lip sinus, midline sinus of the upper lip) Congenital malformations of the dermatoglyphs Congenital smooth muscle hamartoma Cystic lymphatic malformation Dermoid cyst Diffuse neonatal hemangiomatosis Encephalocele Familial disseminated comedones without dyskeratosis Focal facial dermal dysplasia Hutchinson's teeth Hyperkeratotic cutaneous capillary-venous malformation Intrauterine epidermal necrosis Limb–mammary syndrome Lowry–MacLean syndrome Macrocheilia Macrocystic lymphatic malformation Malignant pilomatricoma (pilomatrical carcinoma, pilomatrix carcinoma) Maternal autoimmune bullous disease Median raphe cyst Melanotic neuroectodermal tumor of infancy Membranous aplasia cutis Microcystic lymphatic malformation Midline cervical cleft Mongolian spot (congenital dermal melanocytosis, dermal melanocytosis) Mulberry molar Nager acrofacial dysostosis Nasal glioma (brain-like heterotopia, cephalic brain-like heterotopia, glial hamartoma, heterotopic neuroglial tissue, nasal cerebral heterotopia, nasal heterotopic brain tissue) Nasolacrimal duct cyst Nevus psiloliparus Non-involuting congenital hemangioma Omphalomesenteric duct cyst (omphalomesenteric duct remnant, vitelline cyst) PELVIS syndrome Pilomatricoma (calcifying epithelioma of Malherbe, Malherbe calcifying epithelioma, pilomatrixoma) Poland anomaly Posterior fossa malformations–hemangiomas–arterial anomalies–cardiac defects–eye abnormalities–sternal cleft and supraumbilical raphe syndrome (PHACE association, PHACES syndrome) Preauricular sinus and cyst (ear pit, congenital auricular fistula, congenital preauricular fistula, preauricular cyst) Rapidly involuting congenital hemangioma (congenital nonprogressive hemangioma) Rosenthal–Kloepfer syndrome Rudimentary supernumerary digit (rudimentary polydactyly) SACRAL syndrome Sinus pericranii Skin dimple (skin fossa) Superficial lymphatic malformation (lymphangioma circumscriptum) Supernumerary nipple (accessory nipple, pseudomamma) Thyroglossal duct cyst Verrucous vascular malformation (angiokeratoma circumscriptum naeviforme)
=== Nutrition === One hundred grams of milk chocolate supplies 540 calories. It is 59% carbohydrates (52% as sugar and 3% as dietary fiber), 30% fat and 8% protein (table). Approximately 65% of the fat in milk chocolate is saturated, mainly palmitic acid and stearic acid, while the predominant unsaturated fat is oleic acid (table). One hundred grams of milk chocolate is an excellent source (over 19% of the Daily Value, DV) of riboflavin, vitamin B12 and the dietary minerals manganese, phosphorus and zinc. Chocolate is a good source (10–19% DV) of calcium, magnesium and iron.
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.
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.