The short version of reverse-phase HPLC fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
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.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
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.
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.
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.
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.
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
=== Labour === Tea production in Kenya, Malawi, Rwanda, Tanzania, and Uganda uses child labour, according to the U.S. Department of Labor's List of Goods Produced by Child Labor or Forced Labor. Workers who pick and pack tea on plantations in developing countries can face harsh working conditions and may earn below the living wage. In countries such as Bangladesh, trade unions such as the Bangladesh Tea Workers Women's Forum, led by Gita Rani Kanu, have emerged to campaign for better working conditions for tea workers.
== External links == Edward Calvin Kendall Biography Edward Calvin Kendall on Nobelprize.org "The Lasker Foundation – Clinical Medical Research Award". Retrieved June 6, 2008. "The Passano Foundation, Inc". Retrieved June 6, 2008. [1]
== Regulation of mRNA stability == Pin1, a parvulin, regulates mRNA stability and expression in certain eukaryotics mRNAs. These mRNAs are GM-CSF, Pth, and TGFβ and each of them have AREs, or AU-rich cis-elements. The ARE binding protein KSRP has a Pin1 binding site. Pin1 binds to this site and dephosphorylates the serine and isomerizes the peptide bond between Ser181 and Pro182. This isomerization causes the decay of Pth mRNA. KSRP, and other ARE binding proteins like AUF1, are thought to affect the other mRNAs through mechanisms similar to Pth, with the requirement of a phosphorylated serine bonded to a proline in a specific conformation. Pin1 also triggers proline isomerization of Stem-Loop Binding Protein (SLBP), allowing it to control the dissociation of SLBP from histone mRNA. This leads to Pin1 being able to affect histone mRNA decay. Pin1 affects many other genes in the form of gene silencing through the disruption of cell pathways, making it important in mRNA turnover by modulating RNA binding protein activity.
The Newcomb Cleveland Prize of the American Association for the Advancement of Science (AAAS) is annually awarded to author(s) of outstanding scientific paper published in the Research Articles or Reports sections of Science. Established in 1923, funded by Newcomb Cleveland who remained anonymous until his death in 1951, and for this period it was known as the AAAS Thousand Dollar Prize. "The prize was inspired by Mr. Cleveland's belief that it was the scientist who counted and who needed the encouragement an unexpected monetary award could give." The present rules were instituted in 1975, previously it had gone to the author(s) of noteworthy papers, representing an outstanding contribution to science, presented in a regular session, sectional or societal, during the AAAS Annual Meeting. It is now sponsored by the Fodor Family Trust and includes a prize of $25,000. The prize's current sponsorship has a notable connection to a past winner: Stephen P. A. Fodor, founder of Affymetrix, received the prize in 1990 for a paper introducing microarray technology. Affymetrix added its support to the prize in 2003, more than doubling its monetary value at the time. Winners receive a bronze medal, a share of the prize money, and reimbursement for travel to the AAAS Annual Meeting. Final selection is determined by a panel of distinguished scientists appointed by the editor-in-chief of Science. The annual contest period runs from the first issue of June through the last issue of the following May. No prize was awarded in 1942–1945, 1948, 1973, 1975, or 1976.
Sources: en.wikipedia.org
Arby's Restaurant Group, Inc., doing business as Arby's, is an American fast food sandwich restaurant chain with more than 3,200 restaurants. The flagship property of Inspire Brands, it ranked third in systemwide sales in the United States in the quick-service and fast-casual restaurant industries in 2012, behind Subway and Panera Bread. In October 2017, Food & Wine called Arby's "America's second largest sandwich chain (after Subway)". Roark Capital Group acquired 81.5% of Arby's Restaurant Group in July 2011 and is now a majority-owner of Inspire Brands. The Wendy's Company held a minority stake of 18.5% in Arby's after the acquisition by Roark Capital. That share was reduced to 12.3% upon the purchase of Buffalo Wild Wings. It was sold back to Inspire Brands on August 16, 2018 for $450 million, a 38% premium. Arby's is best known for selling roast beef sandwiches. Other menu items the chain is known for include gyros, wraps, chicken sandwiches, and milkshakes. Its headquarters are in Sandy Springs, Georgia, a suburb of Atlanta that uses Atlanta mailing addresses. As of August 2026, there were 3,206 restaurant locations, down from 3,472 in 2019. There are locations in seven countries outside the United States: Canada, Costa Rica, Egypt, Mexico, Saudi Arabia, South Korea and Turkey.
=== Secretion of Interleukin-10 === Genetically engineered L. lactis can secrete the cytokine interleukin-10 (IL-10) for the treatment of inflammatory bowel diseases (IBD), since IL-10 has a central role in downregulating inflammatory cascades and matrix metalloproteinases. A study by Lothar Steidler and Wolfgang Hans shows that in situ synthesis of IL-10 by genetically engineered L. lactis requires much lower doses than systemic treatments like antibodies to tumor necrosis factor (TNF) or recombinant IL-10. The authors propose two possible routes by which IL-10 can reach its therapeutic target. Genetically engineered L. lactis may produce murine IL-10 in the lumen, and the protein may diffuse to responsive cells in the epithelium or the lamina propria. Another route involves L. lactis being taken up by M cells because of its bacterial size and shape, and the major part of the effect may be due to recombinant IL-10 production in situ in intestinal lymphoid tissue. Both routes may involve paracellular transport mechanisms that are enhanced in inflammation. After transport, IL-10 may directly downregulate inflammation. In principle, this method may be useful for intestinal delivery of other protein therapeutics that are unstable or difficult to produce in large quantities and an alternative to the systemic treatment of IBD.
== External links == IUPHAR GPCR Database – GHRH receptor Archived 2016-03-03 at the Wayback Machine somatotropin+releasing+hormone+receptor at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
Sources: en.wikipedia.org
== Structure == Peptoid oligomers are known to be conformationally unstable, due to the flexibility of the main-chain methylene groups and the absence of stabilizing hydrogen bond interactions along the backbone. Nevertheless, through the choice of appropriate side chains it is possible to form specific steric or electronic interactions that favour the formation of stable secondary structures like helices, especially peptoids with C-α-branched side chains are known to adopt structure analogous to polyproline I helix. Different strategies have been employed to predict and characterize peptoid secondary structure, with the ultimate goal of developing fully folded peptoid protein structures The cis/trans amide bond isomerization still leads to a conformational heterogeneity which doesn’t allow for the formation of homogeneous peptoid foldamers. Nonetheless, scientists were able to find trans-inducer N-Aryl side chains promoting polyproline type II helix, and strong cis-inducer such as bulky naphtylethyl and tert-butyl side chains. It was also found that n→π* interactions can modulate the ratio of cis/trans amide bond conformers, until reaching a complete control of the cis conformer in the peptoid backbone using a functionalizable triazolium side chain.
In 1973, the borough increased in size when the West Rouge area, formerly within the Township of Pickering, was transferred to it with the creation of the Regional Municipality of Durham. The borough's status was changed to city in 1983. The number of aldermen was increased to 14 and the term of office extended to three years from two.
The majority of the population of Jammu and Kashmir is Muslim and a large minority is Hindu. Most Muslims in Jammu and Kashmir belong to the Sunni sect of Islam, especially the Gurjars, Bakarwals, Sayids, Pathans, Sheikhs, Mughals, Paharis, and Doms. As per the 2011 census of India, about 68.3% of people in Jammu and Kashmir were Muslims. Hindu made up around 28.4% of the population. Other small religious groups included Sikhs at 1.9%, Buddhists at 0.9%, and Christians at 0.3%. The population of the Kashmir Division is predominantly Muslim (96.41%) with small Hindu (2.45%) and Sikh (0.81%) communities. Shias are mostly concentrated in the Budgam district, where they form about 30–40% of the population. Among the Kashmiri Hindus, the Pandits are a significant group. The Jammu Division is predominantly Hindu (67.5%) with a significant Muslim population (30%). The Muslims form a majority in the Rajouri (63%), Poonch (90%), Doda (54%), Kishtwar (58%) and Ramban (71%) districts of Jammu, while the Hindus form a majority in Kathua (88%), Samba (86%), Jammu (84%) and Udhampur (88%) districts. Reasi district has an almost equal number of Hindus and Muslims. Most Dogras in the region are Hindus and belong to various Hindu castes. Paharis include both Hindu and Muslims. The Gurjars and Bakarwals are predominantly Sunni Muslims.
The unidirectionality of the system is a result from both the asymmetric skew of the helicene moiety as well as the strain of the cyclic urethane which is formed in c. This strain can be only be lowered by the clockwise rotation of the triptycene rotor in d, as both counterclockwise rotation as well as the inverse process of d are energetically unfavorable. In this respect the preference for the rotation direction is determined by both the positions of the functional groups and the shape of the helicene and is thus built into the design of the molecule instead of dictated by external factors.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Reports describe effects on GABA-A receptor expression, monoamine turnover, and neurotrophic factor levels. These are proposed mechanisms drawn mainly from animal models. No single molecular target has been established.