mass spectrometry 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.
Last reviewed on 2025-10-16. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
Peptide stability depends strongly on temperature, moisture, and pH. Lyophilized Selank is generally most stable when stored cold and dry, with freezer temperatures commonly used for long-term storage. In solution, the compound is susceptible to hydrolysis and to microbial growth if it is not handled aseptically. The C-terminal proline-rich extension appears to slow enzymatic cleavage relative to tuftsin, though quantitative degradation rates vary with the matrix and the conditions tested. Published stability data specific to Selank remain sparse.
| 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 |
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.
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.
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.
Once dissolved, the peptide is markedly less stable than the dry powder. Aqueous solutions are subject to backbone hydrolysis and to microbial growth when they are handled without sterile technique. Buffered solutions near neutral pH are common for short-term laboratory work, while acidic conditions are sometimes used to improve solubility. Analytical laboratories generally prepare working solutions fresh rather than storing them, and a residual water film left in a reopened vial can seed degradation even when the container appears dry.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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=== Use in the removal of phenolic compounds from wastewater === Researchers have found spongin to be useful in the photocatalytic degradation and removal of bisphenols (such as BPA) in wastewater. A heterogeneous catalyst consisting of a spongin scaffold for iron phthalocyanine (SFe) in conjunction with peroxide and UV radiation has been shown to remove phenolic wastes more quickly and efficiently than conventional methods. Other research using spongin scaffolds for the immobilization of Trametes versicolor Laccase has shown similar results in phenol degradation.
== History == Tom Kudirka, originally from Omaha, Nebraska, and an alumnus of Bellevue West High School, had studied business information systems and electronics before moving to Tulsa to work for Lucent Technologies as a field engineer. Thereafter, he had established multimedia companies, including one dealing with speech recognition. Because Kudirka "thought he was bored", he founded 2015 in Tulsa in May 1997. The name was said to have been chosen for an undisclosed "very significant" reason, although Kudirka later said he did not know what it meant. Kudirka recruited developers he had discovered online and had them relocate to Tulsa. The designer Zied Rieke was the first hire. Through Kudirka's connections with Ritual Entertainment and its CEO, 2015 came to develop Wages of Sin, an expansion pack for Ritual Entertainment's 1998 game Sin. It was released in February 1999. On April 3, 2000, 2015 announced the opening of its Trainwreck Studios division for budget-price games with a wider target audience. The first game therein, Laser Arena, was designed to be playable by Kudirka's three-year-old son and released in September 2000. 2015 was simultaneously working on its third game, Heavy Gear Extreme. The company grew to 15 people, requiring it to expand its office space at 8282 South Memorial Drive. The second Trainwreck Studios game, CIA Operative: Solo Missions, was released in May 2001. 2015 was reported as developing Half-Life: Hostile Takeover as an expansion for Half-Life in November 1999.
Sources: en.wikipedia.org
==== Wound healing ==== Nanogels are a promising technology being explored to aid in the wound healing process. Given their ability to encapsulate various types of cargo, nanogels can strategically deliver anti-inflammatory agents, antimicrobial drugs, and necessary growth factors to facilitate new tissue growth and blood vessel formation. Chitosan-based nanogels have demonstrated an improved wound healing effect in previous studies. Chitosan-based nanogels encapsulating interleukin-2 were successfully used to stimulate the immune system and advance the wound healing process. Additionally, chitosan-based nanogels carrying an antibiotic, silver sulfadiazine, were found to decrease the size of second-degree burns in one in vivo study. In another study, silver-loaded nanogels were synthesized in a natural polymer-based solution containing aloe vera, and the presence of aloe vera led to increased healing and a decrease in wound size. With the goal of preventing infection and accelerating the healing process, one group has also published a new nanogel design consisting of an encapsulating core and a functionalized outer surface capable of targeting bacteria present in wounds.
After the deaths of three successive elderly Soviet leaders since 1982, the Soviet Politburo elected Gorbachev Communist Party General Secretary in March 1985, marking the rise of a new generation of leadership. Under Gorbachev, relatively young reform-oriented technocrats, who had begun their careers in the heyday of "de-Stalinization" under reformist leader Nikita Khrushchev, rapidly consolidated power, providing new momentum for political and economic liberalization, and the impetus for cultivating warmer relations via glasnost and trade with the West. Historian Sheila Fitzpatrick wrote that Gorbachev looked on these reforms "through the prism of the Thaw, as a revitalization of socialism rather than an abandonment of it."
=== Relative humidity and temperature === Inconsistent relative humidity and temperature provide the perfect environment for mold and fungi growth on waterlogged wood. Growth of mold or other bacteria requires immediate attention to control damage. Natural cellulosic materials are the best environment for mold spores to grow and mature. "Mold is a microorganism that produces enzymes that convert the cellulose in fibers to soluble sugar that is metabolized as food. Proteins are generally less susceptible, but keratinophilic fungi will feed on, and damage, these fibers as well". Similar to wood found in nature, mold and other feeding organisms are attracted to the material, this includes pests and naturally occurring fungi and bacteria. Mold is a high risk for waterlogged wood even with controlled relative humidity and temperature due to the resilient nature of the organisms and the perfect environment waterlogged wood provides as a food source to the growth of spores.
Since the 1950s, the incidence of type 1 diabetes has been gradually increasing across the world by an average 3–4% per year. The increase is more pronounced in countries that began with a lower incidence of type 1 diabetes.
Sources: en.wikipedia.org
=== Photoaffinity labeling === Unlike ABPP, which results in protein labeling upon probe binding, photoaffinity labeling probes require activation by photolysis before covalent bonding to a protein occurs. The presence of a photoreactive group makes this possible. These probes are composed of three connected moieties: (1) a drug scaffold; (2) a photoreactive group, such as an phenylazide, phenyldiazirine, or benzophenone; and (3) an identification tag, such as biotin, a fluorescent dye, or a click chemistry handle. The drug scaffold is typically an analog of a drug whose mechanism is being studied, and, importantly, binds to the target reversibly, which better mimics the interaction between most drugs and their targets. There are several varieties of photoreactive groups, but they are fundamentally different from ABPP probes: while ABPP specifically labels nucleophilic amino acids in a target's active site, photoaffinity labeling is non-specific, and thus is applicable to labeling a wider range of targets. The identification tag will vary depending on the type of analysis being done: biotin and click chemistry handles are suitable for enrichment of labeled proteins prior to mass spectrometry based identification, while fluorescent dyes are used when using a gel-based imaging method, such as SDS-PAGE, to validate interaction with a target.
===== Ring-opening polymerization ===== With ring-opening polymerization, automated synthesis has been used for rapid screening and optimization, including with catalyst + initiator systems and their polymerization conditions. For example, Hoogenboom et al. determined the optimal temperature for the polymerization of 2-ethyl-2-oxazoline in dimethylacetamide (DMAc), allowing for individual heating of the parallel reactors, which shortened the time needed for preparation and analysis.
=== Insomnia === Prazosin has been said to be the only selective α1-adrenergic receptor antagonist which has been used in the treatment of insomnia to any significant degree. It is used at doses of 1 to 12 mg for this purpose. The combination of prazosin and the beta blocker timolol may produce greater sedative effects than either of them alone.
Coding regions are composed of codons, which are decoded and translated into proteins by the ribosome; in eukaryotes usually into one and in prokaryotes usually into several. Coding regions begin with the start codon and end with a stop codon. In general, the start codon is an AUG triplet and the stop codon is UAG ("amber"), UAA ("ochre"), or UGA ("opal"). The coding regions tend to be stabilized by internal base pairs; this impedes degradation. In addition to being protein-coding, portions of coding regions may serve as regulatory sequences in the pre-mRNA as exonic splicing enhancers or exonic splicing silencers.
== Prognosis == Addiction is generally understood as a chronic, relapsing condition rather than one resolved in a single episode of care, and long-term outcomes vary widely. A systematic review and meta-analysis of long-term follow-up studies estimated that between 35% and 54% of people with a substance use disorder achieved remission (defined as no longer meeting diagnostic criteria for at least six months) but that this typically occurred only after a mean follow-up of around 17 years, with roughly 7–9% of cases remitting in any given year. Its authors concluded that for a substantial proportion of people the condition behaves more like a long-term than an acute disorder, and argued for treatment models designed around chronicity. Substance use disorders are treatable: there is evidence of clinically significant benefit for medications in opioid, nicotine and alcohol use disorders, for behavioral therapies across all substance use disorders, and for neuromodulation in nicotine use disorder.
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.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.