This is a working overview of Regulatory peptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-03-07 and is reviewed periodically as new material appears.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C33H57N11O9 | Free peptide form |
| Molecular mass | About 751.9 Da | Calculated average mass |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form TKPRPGP |
| Structural basis | Tuftsin analogue | Extended version of a natural tetrapeptide |
| Development origin | Russian Academy of Sciences | Work carried out from the 1980s onward |
Pharmacokinetic data are limited. Like most short peptides, Selank is vulnerable to plasma and tissue peptidases, and its measured half-life in circulation is short, on a minutes scale. The Pro-Gly-Pro tail slows this degradation but does not eliminate it. Intranasal administration is the route described in most reports, with absorption through the nasal mucosa and a hypothesized path into the central nervous system that avoids the blood-brain barrier. Direct measurements of human brain exposure are unavailable, so distribution claims rest on inference from animal work.
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.
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.
Acantharea, a relatively large group of marine radiolarian protozoa, produce intricate mineral skeletons composed of strontium sulfate. In biological systems, calcium is substituted to a small extent by strontium. In the human body, most of the absorbed strontium is deposited in the bones. The ratio of strontium to calcium in human bones is between 1:1000 and 1:2000, roughly in the same range as in the blood serum.
In 1955, Harry Winokur worked with brother-in-law William Rosenberg, the founder of Dunkin' Donuts. After Winokur broke his partnership with Rosenberg, he went on to create Mister Donut with his son-in-law, David Slater that same year, with stores in most of North America. The Mister Donut business became so popular that Winokur and Slater decided to go into franchising. As a result, Mister Donut began a rapid expansion that resulted in the opening of 275 stores in the U.S. and Canada. In 1970, Minneapolis-based International Multifoods Corporation, one of the world's largest and most successful food companies, acquired Mister Donut and its franchising concept from Winokur. The first Mister Donut outlet in Japan opened in Minoh, Osaka in 1971. Also in the same year, a Mister Donut training center was constructed in Japan. In 1973, the French cruller became available in Japanese stores. In 1978, brothers Sutthichai and Sutthikiat Chirathiwat, on behalf of Thai Franchise Co., Ltd, opened the first Mister Donut store in Siam Square, Bangkok. The two would come to pioneer the donut market within Thailand. In 2003, Mister Donut in Thailand came under the management of CRG. Donut Thailand (Central Restaurants Group) which continues to manage the company in Thailand. In 1983, Duskin Co., Ltd. of Osaka, Japan, acquired the rights to franchise Mister Donut throughout Japan and Asia.
== External links == UniProt: Bisphosphoglycerate mutase - Homo sapiens (Human) UniProt-Information about bisphosphoglycerate mutase A live model of the effect of changing 2,3-bisphosphoglycerate on the oxyhaemoglobin saturation curve
In molecular biology, the cyanobacterial clock proteins are the main circadian regulator in cyanobacteria. The cyanobacterial clock proteins comprise three proteins: KaiA, KaiB and KaiC. The kaiABC complex may act as a promoter-nonspecific transcription regulator that represses transcription, possibly by acting on the state of chromosome compaction. This complex is expressed from a KaiABC operon. In the complex, KaiA enhances the phosphorylation status of kaiC. In contrast, the presence of kaiB in the complex decreases the phosphorylation status of kaiC, suggesting that kaiB acts by antagonising the interaction between kaiA and kaiC. The activity of KaiA activates kaiBC expression, while KaiC represses it. Also in the KaiC family is RadA/Sms, a highly conserved eubacterial protein that shares sequence similarity with both RecA strand transferase and lon protease. The RadA/Sms family are probable ATP-dependent proteases involved in both DNA repair and degradation of proteins, peptides, glycopeptides. They are classified in as non-peptidase homologues and unassigned peptidases in MEROPS peptidase family S16 (lon protease family, clan SJ). RadA/Sms is involved in recombination and recombinational repair, most likely involving the stabilisation or processing of branched DNA molecules or blocked replication forks because of its genetic redundancy with RecG and RuvABC.
206Pb is the final step in the decay chain of 238U, the "radium series" or "uranium series". In a closed system, over time, a given mass of 238U will decay in a sequence of steps culminating in 206Pb. The production of intermediate products eventually reaches an equilibrium (though this takes a long time, as the half-life of 234U is 245,500 years). Once this stabilized system is reached, the ratio of 238U to 206Pb will steadily decrease, while the ratios of the other intermediate products to each other remain constant. Like most radioisotopes found in the radium series, 206Pb was initially named as a variation of radium, specifically radium G. It is the decay product of both 210Po (historically called radium F) by alpha decay, and the much rarer 206Tl (radium EII) by beta decay. Lead-206 has been proposed for use in fast breeder nuclear fission reactor coolant over the use of natural lead mixture (which also includes other stable lead isotopes) as a mechanism to improve neutron economy and greatly suppress unwanted production of highly radioactive byproducts.
Sources: en.wikipedia.org
== Further reading == Manna, Utpal; Sritharan, S. S. (2007). "Lyapunov Functionals and Local Dissipativity for the Vorticity Equation in Lp and Besov spaces". Differential and Integral Equations. 20 (5): 581–598. arXiv:0802.2898. doi:10.57262/die/1356039440. S2CID 50701138. Barbu, V.; Sritharan, S. S. (2000). "M-Accretive Quantization of the Vorticity Equation" (PDF). In Balakrishnan, A. V. (ed.). Semi-Groups of Operators: Theory and Applications. Boston: Birkhauser. pp. 296–303. Krigel, A. M. (1983). "Vortex evolution". Geophysical & Astrophysical Fluid Dynamics. 24 (3): 213–223. Bibcode:1983GApFD..24..213K. doi:10.1080/03091928308209066.
==== Unstructured ==== An unstructured repository may simply be a stack of tapes, DVD-Rs or external HDDs with minimal information about what was backed up and when. This method is the easiest to implement, but unlikely to achieve a high level of recoverability as it lacks automation.
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar hexagonal ring with one hydrogen atom attached to each. As it contains only carbon and hydrogen atoms, benzene is a hydrocarbon. Benzene is a natural constituent of petroleum and is one of the elementary petrochemicals. Because of the cyclic continuous pi bonds between the carbon atoms and satisfying the rules of aromaticity and Hückel's rule, benzene is classed as an aromatic hydrocarbon. Benzene is a colorless and highly flammable liquid with a sweet smell, and is partially responsible for the aroma of gasoline. It is used primarily as a precursor to the manufacture of chemicals with more complex structures, such as ethylbenzene and cumene, of which billions of kilograms are produced annually. Although benzene is a major industrial chemical, it finds limited use in consumer items because of its toxicity. Benzene is a volatile organic compound. Benzene is classified as a carcinogen. Its particular effects on human health, such as the long-term results of accidental exposure, have been reported on by news organizations such as The New York Times. For instance, a 2022 article stated that benzene contamination in the Boston metropolitan area created hazards in multiple places and may eventually cause some cases of leukemia.
Thermal degradation: Decomposition occurs rapidly at temperatures above 130°C, producing nicotinamide (NAM) and ribose. Degradation kinetics: NRCl degradation follows pseudo-first-order kinetics, with the degradation rate doubling for every 10°C increase in temperature. At pH 7.4, degradation is significantly faster than in acidic conditions, highlighting the importance of pH control for formulation stability. These properties emphasize the need for careful formulation strategies to ensure NRCl's stability during storage, processing, and delivery.
Sources: en.wikipedia.org
It is a seven-amino-acid peptide, Thr-Lys-Pro-Arg-Pro-Gly-Pro, produced by chemical synthesis rather than extracted from biological tissue. Its design is based on tuftsin, a natural immunomodulatory tetrapeptide. The C-terminal Pro-Gly-Pro segment is a common stabilising motif in short regulatory peptides.
The core four residues correspond to tuftsin, which occurs naturally as part of immunoglobulin G. The full seven-residue sequence, however, is not a known endogenous peptide. It is a laboratory-designed analogue intended to combine tuftsin-like activity with greater resistance to breakdown.
No single receptor has been confirmed as the primary target. Reports describe involvement of the GABAergic system, interference with enkephalin degradation, and shifts in neurotrophic factor expression. Because these observations come from different models and assays, they have not yet been integrated into one accepted mechanism.
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.