A practical reference on mass spectrometry: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-02-15 and is reviewed periodically as new material appears.
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.
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.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
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.
| 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 |
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
Lyophilized Selank, the dry powder form, is generally stored frozen at minus 20 degrees Celsius or colder for long-term keeping. The solid is hygroscopic and should stay sealed, dry, and protected from light. Once dissolved, the peptide is less stable and is usually held refrigerated at 2 to 8 degrees Celsius for short periods. Repeated freezing and thawing is avoided because it can promote aggregation and loss of activity. Buffers and pH choice also affect how long a solution remains usable.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
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.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
Low rate of homologous RNA recombination in paramyxoviruses probably results from this unusual genomic requirement for polyhexameric length (6n+0). Natural high genomic stability of SeV is a positive feature for it potential use as a vaccine vector or as an oncolytic agent. For any clinical or industrial applications, it is important that SeV genomic and inserted foreign genes would be expressed in a stable way. Due to SeV genetic stability, multiple serial passages of the virus construct in cell cultures or embryonated chicken eggs without drastic genomic changes are possible. SeV constructs are known to stably express a wide variety of heterologous antigens.
== History == The sucrose hemolysis test was developed in the 1960s. Hartmann and Jenkins first described the test in 1966. The test was devised as a superior screen for PNH compared to the Ham's acid hemolysis test (HT) that was developed in the 1930s. For decades, these two tests were the primary methods of diagnosing PNH. The test is now obsolete being replaced by more advanced methods such as flow cytometry with monoclonal antibodies CD55/CD59 that target glycosylphosphatidylinositol-anchored proteins (GPI-AP) with the addition of inactivated fluorescently labeled bacterial toxins, such as fluorescently labeled aerolysin (FLAER). Flow cytometry is the most sensitive and useful assay currently available to screen and diagnosis PNH.
== Structure determination == Bottromycin is produced naturally as a series of products differing in methylation patterns. All products contain valine and phenylalanine methylation. Bottromycin A2 is singly methylated on proline, bottromycin B lacks methylation on proline, and bottromycin C contains a doubly methylated proline. A partial structure of bottromycin was reported shortly after the initial discovery of bottromycin. The first structural studies relied on traditional methods of analysis. Its peptide-like structure, including the presence of glycine and valine, was first suggested by a combination of acidic hydrolysis, acetylation, ninhydrin staining, and paper chromatography, among other experiments. The presence of a thiazole ring, along with an adjacent β-methylated phenylalanine, was established by ninhydrin staining, potassium permanganate oxidation, and comparison to synthetic standards. A methyl ester substituent was reported in 1958. The same study also reported that the Kunz hydrolysis product lacking a methyl ester was biologically inactive. Nakamura and colleagues later reported that bottromycin contained tert-leucine and cis-3-methylproline. They also proposed a linear iminohexapeptide structure.
Sources: en.wikipedia.org
=== Isotope preparation === Curium is made in small amounts in nuclear reactors, and by now only kilograms of 242Cm and 244Cm have been accumulated, and grams or even milligrams for heavier isotopes. Hence the high price of curium, which has been quoted at 160–185 USD per milligram, with a more recent estimate at US$2,000/g for 242Cm and US$170/g for 244Cm. In nuclear reactors, curium is formed from 238U in a series of nuclear reactions. In the first chain, 238U captures a neutron and converts into 239U, which via β− decay transforms into 239Np and 239Pu.
== Conservation status == Rattlesnakes tend to avoid developed areas, preferring undisturbed, natural habitats. Rapid habitat destruction by humans, mass killings during events such as rattlesnake round-ups, and deliberate extermination campaigns all pose threats to rattlesnake populations in many areas. Several species, such as the timber rattlesnake, massasauga, and canebrake rattlesnake, are listed as threatened or endangered in many U.S. states. Many rattlesnakes die from being run over by cars. In more heavily populated and trafficked areas, reports have been increasing of rattlesnakes that do not rattle. This phenomenon is falsely attributed to selective pressure by humans, who often kill the snakes when they are discovered. However, snake experts have dismissed this theory, stating that snakes simply do not rattle as often as laymen expect them to, and that snakes that live near populated areas simply get used to people passing by, only rattling when a person lingers too long or gets too close.
==== Rongxian-Weiyuan campaign (late 1932–early 1933) ==== From his Meishan headquarters, Liu concentrated his forces in Rongxian and Weiyuan. Despite the ceasefire, he still did not trust Deng and Tian, fearing their betrayal if he were to fight Liu Xiang, trapping him in a pincer maneuver. To solve this strategic impasse, Liu proposed a strategic withdrawal: the bulk of his army was to retreat from northern Sichuan into Shaanxi and Gansu, only to attack Deng and Tian from the north. However, due to a combination of poor winter weather and his officers' unwillingness to attack their Baoding classmates, he was forced to shelve the plan. The campaign has been described as unprecedentedly fierce. Over 5,000 deaths were reported at the twin battles of Jiangjiachang and Laojuntai. Seizing on his momentum, Liu Xiang then convened a conference at Neijiang calling for the unification of Sichuan and the surrender of Liu Wenhui. Liu Wenhui's forces were ultimately defeated when Deng Xihou ordered Tian Songyao to attack them from the rear.
Sources: en.wikipedia.org
23 October A significant breakthrough in treating cervical cancer is reported by University College London, with participants in a Phase III trial seeing a 35% reduction in the risk of both mortality or the disease returning. The study used a combination of existing, cheap drugs ahead of usual radiotherapy treatment. The Royal Mint unveil a special Christmas 50 pence coin, celebrating the 1978 picture book The Snowman by Raymond Briggs. British-Israeli Yosef Guedalia is named as another victim killed by Hamas in the 7 October attack. Sunak tells parliament the UK has judged the al-Ahli Arab Hospital explosion, which occurred on 17 October, was likely caused by "a missile, or part of one" fired from "within Gaza". COVID-19 in the UK: Hospitals ask visitors to wear face-coverings amidst a rise in COVID-19 cases. 24 October Office for National Statistics data shows that UK unemployment remained at 4.2% in the three months up to August 2023. A BBC investigation finds that UK authorities failed to act on multiple official warnings about an online forum promoting suicide connected to at least 50 UK deaths. Immigration Minister Robert Jenrick confirms that the UK government will stop using 50 hotels to accommodate asylum seekers by January 2024. Local officials subsequently warn that local authorities may be forced to pay for use of the hotels instead. The Financial Conduct Authority confirms that the cap on bankers' bonuses, introduced in 2014, will be lifted from 31 October as part of post-Brexit financial reforms.
== History == In 1822 the first awards were given to thirteen people by the Philadelphia Society for Promoting Agriculture entrusted by the "Corporation of the city of Philadelphia". The druggist John Scott of Edinburgh organized a $4,000 fund which, after his death in 1815 was administered by a merchant until the first award, a copper medal and "an amount not to exceed twenty dollars", was given in 1822. (At the time, $20 could buy one ox or a 12-volume encyclopedia.) Several hundred recipients have since been selected by the City Council of Philadelphia, which decides from the annual list of nominees made by the Franklin Institute.
In Thai cuisine, glass noodles are called wun sen (Thai: วุ้นเส้น). They are commonly mixed with pork and shrimp in a spicy salad called yam wun sen (Thai: ยำวุ้นเส้น), or stir-fried as phat wun sen (Thai: ผัดวุ้นเส้น) and sometimes used as the noodles for pad thai.
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 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.