proteolysis 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.
Updated 2026-06-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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 studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
| 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 |
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.
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.
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.
Major challenges to the use of cecropins as cancer therapeutics are delivery of the peptides to tumor cells. Repeated administration of peptides is necessary to maintain systemic levels of cecropins at sufficient concentrations for anti-cancer activity. This need for repeated administration complicates potential treatment plans. One proposed alternative suggests use of gene therapy to introduce cecropin genes into cancer cells. A study in which cecropin genes were expressed in a human bladder carcinoma cell line showed that tumor cells bearing cecropin genes have reduced tumorigenicity, up to complete loss of tumorigenicity in some cell clones. More recent studies have identified new cecropins, which may be prove useful in development of cancer therapeutics. For example, genome and transcriptome analyses of the spruce budworm Choristoneura fumiferana resulted in identification of novel cecropins which differ from previously characterized cecropins in that they are negatively charged, rather than positively charged. A BH3-like motif (amino acid sequence G-[KQR]-[HKQNR]-[IV]-[KQR]) is present in both anionic and cationic cecropins, and analysis suggests that this motif may interact with Bcl-2, a protein implicated in apoptosis. Further study of cecropin structure and anticancer properties may inform design of novel cancer therapeutics.
First-level members are called aşıks عاشق (Albanian: ashik). They are those who, while not having taken initiation into the order, are nevertheless drawn to it. Following initiation (called nasip), one becomes a mühip محب (Albanian: muhib). After some time as a mühip, one can take further vows and become a dervish. The next level above dervish is that of baba. The baba (lit. father) (Albanian: atë) is considered to be the head of a tekke and qualified to give spiritual guidance (irshad إرشاد). Above the baba (Albanian: gjysh) is the rank of halife-baba (or dede, grandfather). The dedebaba (Albanian: kryegjysh) is traditionally considered to be the highest ranking authority in the Bektashi order. Traditionally the residence of the dedebaba was the Pir Evi (The Saint's Home) which was located in the shrine of Hajji Bektash Wali in the central Anatolian town of Hacıbektaş (aka Solucakarahüyük), known as the Hajibektash complex. Traditionally there were twelve of these hierarchical rankings, the most senior being the dedebaba (great-grandfather).
In the 13th and 14th centuries, some pilgrims to Canterbury journeyed via Billericay. Some of them may have spent the night in the town before crossing the river Thames at Tilbury; this may account for the large number of inns. The town's most notable historical episode was the Battle of Billericay during the Peasants' Revolt of 1381.
=== From end-of-life batteries === A few small companies are recycling spent batteries, focusing on recovering copper and cobalt. Some recover lithium carbonate alongside the compound Li2Al4(CO3)(OH)12⋅3H2O also.
== Preparation of azide == The aforementioned conversion to acyl azide has been carried out multifariously; Bergmann utilized methyl ester and hydrazide, whereas more recent attempts have designed methods such as: nitrosylation of N-formylaminoacyl hydrazide and subsequent substitution by sodium azide, reaction of a carboxylic acid with diphenyl phosphorazidate, triethylamine, and a hydroxyl component, and reaction between TMS azide and the anhydride of an amino acid.
Sources: en.wikipedia.org
== Invertebrates == In some invertebrates, such as Porifera, Cnidaria, Ctenophora, and some triploblasts (namely the acoelomates), the term "mesenchyme" refers to a more-or-less solid but loosely organized tissue that consists of a gel matrix (the mesoglea) with various cellular and fibrous inclusions, located between the epidermis and the gastrodermis (non-triploblast animals usually are considered to lack "connective" tissue). In some cases, the mesoglea is noncellular.
=== Storage === Chocolate is very sensitive to temperature and humidity. Ideal storage temperatures are between 15 and 17 °C (59 and 63 °F), with a relative humidity of less than 50%. If refrigerated or frozen without containment, chocolate can absorb enough moisture to cause a whitish discoloration, the result of fat or sugar crystals rising to the surface. Various types of "blooming" effects can occur if chocolate is stored or served improperly. Chocolate bloom is caused by storage temperature fluctuating or exceeding 24 °C (75 °F), while sugar bloom is caused by temperature below 15 °C (59 °F) or excess humidity. A fat bloom can be distinguished by touch; it disappears if the surface of affected chocolate is lightly rubbed. Although visually unappealing, chocolate suffering from bloom is safe for consumption and taste is unaffected. Bloom can be reversed by retempering the chocolate or using it for any use that requires melting the chocolate. Chocolate is generally stored away from other foods, as it can absorb aromas. To avoid this, chocolate is packed or wrapped, then stored in darkness, in ideal humidity and temperature conditions.
=== Medication === Gynecomastia can respond well to medical treatment, although it is usually effective only when done within the first two years after the start of male breast enlargement. Selective estrogen receptor modulators (SERMs) such as tamoxifen, raloxifene, and clomifene may be beneficial in the treatment of gynecomastia but are not approved by the Food and Drug Administration for use in gynecomastia. Clomifene seems to be less effective than tamoxifen or raloxifene. Tamoxifen may be used to treat gynecomastia in adults, and of the medical treatments used, tamoxifen is the most effective. Recent studies have shown that treatment with tamoxifen may represent a safe and effective mode of treatment in cases of cosmetically disturbing or painful gynecomastia. Aromatase inhibitors (AIs) such as anastrozole have been used off-label for cases of gynecomastia occurring during puberty but are less effective than SERMs. A few cases of gynecomastia caused by the rare disorders aromatase excess syndrome and Peutz–Jeghers syndrome have responded to treatment with AIs such as anastrozole. Androgens/anabolic steroids may be effective for gynecomastia. Testosterone itself may not be suitable to treat gynecomastia as it can be aromatized into estradiol, but nonaromatizable androgens like topical androstanolone (dihydrotestosterone) can be useful.
=== Nutritive === It maintains the vitality of the surrounding cells. (PDL is heavily anastomosed). There are three principal sources of blood vessels which are apical vessels, perforating vessels and gingival vessels. Apical vessels originate from vessels that supply the pulp. Perforating vessels originate from lamina dura and the vessels perforate the socket wall (cribriform plate). Gingival vessels are derived from the gingival tissue. Outer layers of blood supply in PDL may help in mechanical suspension and support of the tooth while inner layers of blood vessels supply surrounding PDL tissues.
CH3CO2H + H2O ⇌ CH3CO−2 + H3O+ a proton may hop from one molecule of acetic acid onto a water molecule and then onto an acetate anion to form another molecule of acetic acid and leaving the number of acetic acid molecules unchanged. This is an example of dynamic equilibrium. Equilibria, like the rest of thermodynamics, are statistical phenomena, averages of microscopic behavior. Le Châtelier's principle (1884) predicts the behavior of an equilibrium system when changes to its reaction conditions occur. If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to partially reverse the change. For example, adding more S (to the chemical reaction above) from the outside will cause an excess of products, and the system will try to counteract this by increasing the reverse reaction and pushing the equilibrium point backward (though the equilibrium constant will stay the same). If mineral acid is added to the acetic acid mixture, increasing the concentration of hydronium ion, the amount of dissociation must decrease as the reaction is driven to the left in accordance with this principle. This can also be deduced from the equilibrium constant expression for the reaction:
Sources: en.wikipedia.org
15 April to 1 January 1971 The 173rd Airborne Brigade, ARVN 2nd Division and 22nd Division and Regional Force and Popular Forces launched Operation Washington Green a security and pacification operation in Bình Định Province. The operation results in 1,957 PAVN/VC killed, U.S. losses are 227 killed.
To study the effect of various preparation of Testosterone on Steroid Profiling and Delta Value of 13C/12C of Testosterone Metabolite in volunteers with Normal/Abnormal Testosterone/ Epitestosterone (T/E) Ratio. Indian Herbal Drugs : Identification of stimulants, narcotics and other substances with potential of ergogenic aids in sports. Characterization of physiochemical properties and analysis of liposomes in human biological samples using hyphenated analytical technique. Detection of Stanozolol conjugated metabolites by liquid chromatography tandem-mass spectrometry. Prednisone excretion study and identification of its marker metabolites. Rapid determination of urinary phthalates using liquid chromatography tandem mass spectrometry. Identification of various banned small peptides in human urine using liquid chromatography tandem mass spectrometry.
== Medical uses == Mineralocorticoid receptor antagonists are diuretic drugs that work primarily on the kidneys. They decrease sodium reabsorption, which leads to increased water excretion by the kidneys. By regulating water excretion, mineralocorticoid receptor antagonists lower blood pressure and reduce fluid around the heart which can be very beneficial in some cardiovascular conditions. Mineralocorticoid receptor antagonists have been used for many clinical conditions in the cardiovascular system. It has proven beneficial for diseases like primary aldosteronism, primary and resistant hypertension, heart failure and chronic kidney disease. They are often used with other medications, such as ACE inhibitors or beta blockers.
Esimone, Charles, MI Okeke, CU Iroegbu, EN Eze, AS Okoli, "Evaluation of extracts of the root of Landolphia owerrience for antibacterial activity", Journal of ethnopharmacology 78 (2-3), 119-127 Esimone, Charles, KF Chah, CA Eze, CE Emuelosi, "Antibacterial and wound healing properties of methanolic extracts of some Nigerian medicinal plants", Journal of ethnopharmacology 104 (1-2), 164-167 Esimone, Charles, CS Nworu, CL Jackson, "Cutaneous wound healing activity of a herbal ointment containing the leaf extract of Jatropha curcas L.(Euphorbiaceae)", International Journal of Applied Research in Natural Products 1 (4), 1-4 Esimone, Charles, IR Iroha, EC Ibezim, CO Okeh, EM Okpana, "In vitro evaluation of the interaction between tea extracts and penicillin G against Staphylococcus aureus", African Journal of Biotechnology 5 (11) Esimone, Charles, PA Ekwealor, MC Ugwu, I Ezeobi, G Amalukwe, BC Ugwu, U Okezie et al., "Antimicrobial evaluation of bacterial isolates from urine specimen of patients with complaints of urinary tract infections in Awka, Nigeria", International journal of microbiology 2016 (1), 9740273
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.
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.