mass spectrometry is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Updated 2026-07-14. Numbers and descriptions here follow the published literature rather than marketing material.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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 |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Analog of the tetrapeptide tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Reported consistently across pharmacopoeial descriptions |
| Appearance | White to off-white lyophilized powder | Typical form of research-grade material |
| Solubility | Freely soluble in water | Aqueous buffers; poor in nonpolar solvents |
| Typical storage temperature | -20 degrees Celsius | Lyophilized powder; protect from moisture |
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.
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.
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.
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.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
== History == The brewery started as a small, casual pub in the alleyways of Gyeongnidan in Seoul. The idea to start the pub was inspired by Tudor's article in The Economist, which claimed: "brewing remains just about the only useful activity at which North Korea beats the South." The pub began selling Bill's Pale Ale, The Booth's first brew, along with a small selection of pizza. After realizing how crucial the cold chain transportation system was to maintaining the quality and flavor of beer, the owners established the first cold chain import and distribution system, The Booth Cold Chain. This was soon importing beers from Mikkeller, Evil Twin, To Øl, and 8 Wired. Two crowdfunding campaigns titled Equity for Booth were launched, in September 2015 and February 2017.
=== Potential health concerns === Mold is harmful to materials, and may cause mold health issues in humans. When a library collection experiences a mold outbreak, actions need to be taken to ensure preservation of materials and the good health of the people involved. Mold is more hazardous to those who have allergies or suffer from respiratory problems such as asthma. Some mold species can irritate other parts of the body through prolonged exposure. In some cases, protective clothing is necessary when handling mold found on library collections.
President Paul Kruger called a closed council, including Jan Gerrit Bantjes, to discuss the growing problem and it was decided to put a heavy tax on the sale of dynamite to non-Boer residents. Jan G. Bantjes, fluent in both spoken and written Dutch and English, was a close confidant of Paul Kruger with their link dating to the Great Trek days. Jan's father, Jan Gerritze Bantjes, had given Paul Kruger his elementary education during the trek and Jan Gerritse was part of his inner core of associates. This closed council would be the committee which set the Transvaal Republic on a collision course with Great Britain and the Anglo-Boer War 1899-1902 and which set German feelings toward Britain at boiling point by siding with the Boers. Because of this applied dynamite tax, considerable discontent and tensions began to rise. As Johannesburg was largely an Uitlander city, non-boer leaders there began to discuss the proposals for an insurrection. Cecil Rhodes, Prime Minister of the Cape Colony, had a desire to incorporate the Transvaal and the Orange Free State in a federation under British control. Having combined his commercial mining interests with Alfred Beit to form the De Beers Mining Corporation, the two men also wanted to control the Johannesburg gold mining industry. They played a major role in fomenting Uitlander grievances. Rhodes later told the journalist W.T. Stead that he feared that a Uitlander rebellion would cause trouble for Britain if not controlled by him:
Some say we should hold elections tomorrow, those have no chances of being free and fair." and added "Ultimately what the long term political leadership is going be, it’s going to be up to Venezuelans." During a conference in Saint Kitts and Nevis with other Caribbean nations on 25 February, United States Secretary of State Marco Rubio said that the US recognizes the need for fair, democratic elections in Venezuela, saying "We do believe that a prosperous, free Venezuela who’s governed by a legitimate government who has the interests of their people in mind could also be an extraordinary partner and asset to many of the countries represented here today." Juan Pablo Guanipa, ally of Machado and political prisoner released during a mass political prisoner release in Venezuela in 2026, said for Spanish newspaper El País, that elections are under way and that Chavismo has lost its ability to impose conditions.
=== PRC government === The Chinese government said that producers violating the law "could have their licenses revoked and be handed over to law enforcement organs". A senior Agriculture Ministry official said that of a quarter of a million feed-makers and animal farms inspected for melamine contamination, inspectors found more than 500 engaged in "illegal or questionable practices". Some 3,700 tonnes of feed with excessive melamine were seized. Hong Kong regulators have requested certification of exported eggs, but the central government has not yet mounted a centralised response; although mainland authorities already require eggs to be certified as free of avian influenza and Sudan red dye prior to export following previous food-safety scares, the AQSIQ has declined nationwide testing. Local government, for example Guangdong authorities, have increased random inspections at poultry farms. They declared to "harshly crack down on the unlawful behaviour of illegally manufacturing, selling and using melamine".
Sources: en.wikipedia.org
Lisa Sanders in hopes of getting a second opinion, a different diagnosis, or a different treatment. Essentially looking for any route that could lead to a better life for Sadie that doesn't have to hinder her more than her disease hinders her now. Dr. Lisa Sanders put their story out onto her column and awaited for the responses. Many of the responses from the audience agreed with the diagnosis of Rasmussen’s, others suggested that the seizures could be controlled with electro stimulation therapy, and a third group suggested it was a neurologic version of Lyme Disease. She was tested for various diseases under different conditions and one specific test came back strongly positive, resulting in a diagnosis that led to a manageable treatment, and also a responsive neurostimulation device was implanted by a neurosurgeon.
According to Gerard Keown, by 1932 much had been achieved in the quest for an independent foreign policy. The Free State was an established element in the European system and a member of the League of Nations. It had blazed a trail in asserting the rights of the dominions to their own foreign policy, in the process establishing full diplomatic relations with the United States, France, Belgium, Germany, and the Holy See. It was concluding its own political and commercial treaties and using the apparatus of international relations to pursue its interests. It had received the accolade of election to a non-permanent seat on the council of the League of Nations and asserted its full equality with Britain and the other dominions within the Commonwealth. By contrast, the military was drastically reduced in size and scope, with its budget cut by 82% from 1924 to 1929. The active duty forces were reduced from 28,000 men to 7,000. Co-operation with London was minimal.
==== Carbon-nitrogen ==== Monoamine oxidase (MAO) is an extensively studied flavoenzyme due to its biological importance with the catabolism of norepinephrine, serotonin and dopamine. MAO oxidizes primary, secondary and tertiary amines, which nonenzymatically hydrolyze from the imine to aldehyde or ketone. Even though this class of enzyme has been extensively studied, its mechanism of action is still being debated. Two mechanisms have been proposed: a radical mechanism and a nucleophilic mechanism. The radical mechanism is less generally accepted because no spectral or electron paramagnetic resonance evidence exists for the presence of a radical intermediate. The nucleophilic mechanism is more favored because it is supported by site-directed mutagenesis studies which mutated two tyrosine residues that were expected to increase the nucleophilicity of the substrates.
Scytalidocarboxyl peptidase B, also known as Scytalidoglutamic peptidase and Scytalidopepsin B (EC 3.4.23.32, obsolete names include Scytalidium aspartic proteinase B, Ganoderma lucidum carboxyl proteinase, Ganoderma lucidum aspartic proteinase, Scytalidium lignicolum aspartic proteinase B, SLB) is a proteolytic enzyme. It was previously thought to be an aspartic protease, but determination of its molecular structure showed it to belong a novel group of proteases, glutamic protease. The protease has a unique structure and a novel catalytic dyad (E136 and Q53) in its active site. The active-site residues, glutamic acid (E) and glutamine (Q), was used to coin the name of the family of proteases; eqolisins, to which Scytalidoglutamic peptidase B belongs. This enzyme catalyses the following chemical reaction
Trump's reelection in 2024 was met with consternation by Democrats. The three richest men in America attended Trump's second inauguration, and Elon Musk's formation of DOGE, as well as the enactment of Project 2025, were seen as myopic and unconstitutional, featuring policies such as reducing taxes on corporations and capital gains, instituting a flat income tax on individuals, cutting Medicare and Medicaid, reversing President Joe Biden's policies, and reducing environmental protections. After Trump won the election, Sanders released a statement blaming the Democratic Party's abandonment of "working-class people" for its defeat. In February 2025, Sanders began the "Fighting Oligarchy Tour", in which he and Ocasio-Cortez held rallies criticizing Trump's policies and economic inequality. In April 2025, Sanders criticized the administration, saying that its moving "rapidly toward oligarchy", he also called US a "pseudo-democracy". At one rally held in June 2025, Sanders reacted to news of Trump's bombing of Iranian nuclear sites by saying: "The American people are being lied to again today. We cannot allow history to repeat itself". Also in June, Sanders endorsed progressive politician and DSA member Zohran Mamdani for the 2025 New York City Democratic mayoral primary, calling him "best choice" for mayor. In September 2025, Sanders criticized Democratic Party officials for their perceived refusal to support Mamdani after his victory in the New York City mayoral primary.
Sources: en.wikipedia.org
G-protein-coupled receptor kinase 7 (EC 2.7.11.14, GRK7, cone opsin kinase, iodopsin kinase) is a serine/threonine-specific protein kinase involved in phototransduction. This enzyme catalyses the phosphorylation of cone (color) photopsins in retinal cones during high acuity color vision primarily in the fovea.
=== Others === Jessamine Lovelace — the ghost guardian of the London Institute. Also known as Jessamine Gray after her secret marriage to Tessa's brother Nate in The Infernal Devices. Jesse Blackthorn — Tatiana's deceased son and Grace Blackthorn's adoptive brother. His spirit can only be seen by his mother, Grace, and Lucie.
(one-letter sequence: NDECELCVNVACTGCL). Plecanatide is nearly structurally identical to human uroguanylin, apart from the substitution of Asp3 with Glu3. Disulfide bonds exist between Cys4 and Cys12, as well as Cys7 and Cys15. Plecanatide has two important motifs. The first being the acidic residues Asp2 and Glu3 which modulate the affinity for its receptor in response to environmental pH. Simulations predict the optimal activity of Plecanatide to occur at pH 5, making it suitable for targeting cells within the proximal intestine, which has a pH of between 5 and 6. The second is the ACTGC motif (residues Ala11 to Cys15) which is the region responsible for its binding to the receptor, guanylate cyclase-C.
== Side effects == Compared to other tricyclic antidepressants, it produces significantly fewer cardiovascular, anticholinergic (like dry mouth or constipation), sedative and appetite-stimulating effects. Unlike other tricyclic antidepressants, tianeptine does not affect heart function. μ-Opioid receptor agonists (Opioid) can sometimes induce euphoria, as does tianeptine, occasionally, at high doses, well above the normal therapeutic range (see § Recreational use below) which makes them prone for abuse. As such, it is not recommended to use Tianeptine for patients with history of any substance abuse, especially in opioid use disorders. Tianeptine can also cause severe withdrawal symptoms after prolonged use at high doses which should prompt extreme caution when stopping treatment.
Sources: en.wikipedia.org
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.
The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.
It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.
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.