This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-04 and is reviewed periodically as new material appears.
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.
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.
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.
| 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 |
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.
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.
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.
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Animal studies have examined behaviour in tests of anxiety, memory retention and stress response, and several report changes in neurotrophic or neurotransmitter-related markers. The human evidence base is much smaller, consisting mainly of short trials conducted in Russia with limited reporting in English-language journals. Sample sizes are modest and outcome measures vary between studies, so the findings are best described as preliminary. Independent replication under modern trial standards has not been widely reported.
The film received mixed reviews from critics, but DiCaprio's performance was praised and earned him the AACTA Award for Best Actor in a Leading Role. Critic Rafer Guzman of Newsday wrote that DiCaprio was not only "tough [...] but also vulnerable, touching, funny, a faker, a human. It's a tremendous, hard-won performance." Matt Zoller Seitz of Roger Ebert's website described his performance as "the movie's greatest and simplest special effect", and "iconic—maybe his career best". The film grossed $353 million worldwide, more than three times its budget. Three films were produced by DiCaprio under Appian Way in 2013—the ensemble crime thriller Runner Runner, which The Guardian's Xan Brooks described as "a lazy, trashy film that barely goes through the motions"; the commercially failed thriller Out of the Furnace; and the black comedy-drama The Wolf of Wall Street. DiCaprio reunited with Scorsese for the fifth time in The Wolf of the Wall Street, a film based on the life of stockbroker Jordan Belfort (played by DiCaprio), who was arrested in the late 1990s for securities fraud and money laundering. DiCaprio wanted to play Belfort ever since he had read his autobiography and won a bidding war with Warner Bros. against Brad Pitt and Paramount Pictures for the rights to Belfort's memoir in 2007. He was fond of Belfort's honest and unapologetic portrayal of his actual experiences in the book, and was inspired by the 2008 financial crisis to make the film. The Wolf of Wall Street received positive reviews for Scorsese's and DiCaprio's work together.
Pennsylvania Department of Health – The company´s objective is to promote healthy behaviors, prevent injury and disease, and assure the safe delivery of quality health care. License: Pursuant of the act of September 26, 1951, P.L., 1539 as amended, a Permit to operate a Clinical Laboratory.
Multiple methods allow for the quantitation of proteins by mass spectrometry, and recent advances have enabled quantifying thousands of proteins in single cells. Protein quantification by mass spectrometry benefits from efficient sampling (counting) of many ions per protein compared to other methods. Quantifications can be performed by label-free methods and by multiplexed methods, which use isotopic mass tags as labels. Multiplexed methods can improve both quantitative accuracy and throughput. Typically, stable (e.g. non-radioactive) heavier isotopes of carbon (13C) or nitrogen (15N) are incorporated into one sample while the other one is labeled with corresponding light isotopes (e.g. 12C and 14N). The two samples are mixed before the analysis. Peptides derived from the different samples can be distinguished due to their mass difference. The ratio of their peak intensities corresponds to the relative abundance ratio of the peptides (and proteins). The first generation of methods for isotope labeling included SILAC (stable isotope labeling by amino acids in cell culture), trypsin-catalyzed 18O labeling, ICAT (isotope coded affinity tagging), and iTRAQ (isobaric tags for relative and absolute quantitation). The more recent generation of multiplexing methods include tandem mass tags (TMT) for DDA data and mTRAQ for multiplexed DIA (plexDIA). "Semi-quantitative" mass spectrometry can be performed without labeling of samples. Typically, this is done with MALDI analysis (in linear mode).
Sources: en.wikipedia.org
== Structure == Alpha-synuclein in solution is considered to be an intrinsically disordered protein, i.e. it lacks a single stable 3D structure. As of 2014, an increasing number of reports suggest, however, the presence of partial structures or mostly structured oligomeric states in the solution structure of alpha-synuclein even in the absence of lipids. This trend is also supported by a large number of single molecule (optical tweezers) measurements on single copies of monomeric alpha-synuclein as well as covalently enforced dimers or tetramers of alpha-synuclein. Alpha-synuclein is specifically upregulated in a discrete population of presynaptic terminals of the brain during a period of acquisition-related synaptic rearrangement. It has been shown that alpha-synuclein significantly interacts with tubulin, and that alpha-synuclein may have activity as a potential microtubule-associated protein, like tau. Evidence suggests that alpha-synuclein functions as a molecular chaperone in the formation of SNARE complexes. In particular, it simultaneously binds to phospholipids of the plasma membrane via its N-terminus domain and to synaptobrevin-2 via its C-terminus domain, with increased importance during synaptic activity. Indeed, there is growing evidence that alpha-synuclein is involved in the functioning of the neuronal Golgi apparatus and vesicle trafficking. Apparently, alpha-synuclein is essential for normal development of the cognitive functions.
There are a number of factors that have been identified to have provoked the independent movements. First, increasing control by the Crown of its overseas empire via the Bourbon Reforms of the mid-eighteenth century introduced changes to the relationship of Spanish Americans to the Crown. The language used to describe the overseas empire shifted from "kingdoms" with independent standing with the crown to "colonies" subordinate to Spain. In an effort to better control the administration and economy of the overseas possessions the Crown reintroduced the practice of appointing outsiders, almost all peninsulars, to the royal offices throughout the empire. This meant that Spanish American elites were thwarted in their expectations and ambitions by the crown's upending of long-standing practices of creole access to office holding. The regalist and secularizing policies of the Bourbon monarchy were aimed at decreasing the power of the Roman Catholic Church. The crown had already expelled the Jesuits in 1767, which saw many creole members of the Society of Jesus go into permanent exile. By limiting the power of the Church, the crown attempted to centralize itself within the institutions of colonial Spanish America. Because of the physical and ideological proximity that the clergy had, they could directly influence and dictate the interactions between populations of colonial Spanish America, either as legal counsel or an advisor; a directness which the crown would need to attempt to create the centralized, colonial state which it wanted to implement.
Sodium is found in many different minerals, of which the most common is ordinary salt (sodium chloride), which occurs in vast quantities dissolved in seawater. Other solid deposits include halite, amphibole, cryolite, nitratine, and zeolite. Many of these solid deposits occur as a result of ancient seas evaporating, which still occurs now in places such as Utah's Great Salt Lake and the Dead Sea. Despite their near-equal abundance in Earth's crust, sodium is far more common than potassium in the ocean, both because potassium's larger size makes its salts less soluble, and because potassium is bound by silicates in soil and what potassium leaches is absorbed far more readily by plant life than sodium. Despite its chemical similarity, lithium typically does not occur together with sodium or potassium due to its smaller size. Due to its relatively low reactivity, it can be found in seawater in large amounts; it is estimated that lithium concentration in seawater is approximately 0.14 to 0.25 parts per million (ppm) or 25 micromolar. Its diagonal relationship with magnesium often allows it to replace magnesium in ferromagnesium minerals, where its crustal concentration is about 18 ppm, comparable to that of gallium and niobium. Commercially, the most important lithium mineral is spodumene, which occurs in large deposits worldwide. Rubidium is approximately as abundant as zinc and more abundant than copper. It occurs naturally in the minerals leucite, pollucite, carnallite, zinnwaldite, and lepidolite, although none of these contain only rubidium and no other alkali metals.
Sources: en.wikipedia.org
=== Transit === On December 16, 2025, Pritzker signed into law the Illinois People Over Parking Act, which disburses $1.5 billion to address post-COVID-19 budget shortfalls for Chicagoland-area transit authorities to avoid service cuts; reduces the farebox revenue share of total funding from 50% to 25%, since post-pandemic reductions in ridership made these expectations unreasonable; and disburses $169 million to downstate transit agencies to cover similar budget shortfalls. It prevents transit agencies from transferring funding for operations to capital investment. Local jurisdictions are prohibited from establishing minimum parking requirements within half a mile of transit rail stations and bus hubs or one-eighth mile of corridors with combined bus route frequency of 15 minutes or less during peak periods under this legislation. The bill also reorganizes the Regional Transportation Authority into the Northern Illinois Transit Authority, which is intended to centralize decision-making power away from individual counties and synchronize operations of the Chicago Transit Authority, Metra, and Pace. The NITA board is to have 20 members, five assigned by the mayor of Chicago, the Cook County President, and the governor, and five by the five collar counties, where 15 votes are needed to affirm board actions, or 12 if two affirmative votes from each of the four appointing authorities are cast; and a majority of CTA, Metra, and Pace board members are to be simultaneously staffed by NITA board members.
Gladstone finally retired in 1894. Gladstone's support for Home Rule deeply divided the party, and it lost its upper and upper-middle-class base, while keeping support among Protestant nonconformists and the Celtic fringe. Historian R. C. K. Ensor reports that after 1886, the main Liberal Party was deserted by practically the entire whig peerage and the great majority of the upper-class and upper-middle-class members. High prestige London clubs that had a Liberal base were deeply split. Ensor notes that, "London society, following the known views of the Queen, practically ostracized home rulers." The new Liberal leader was the ineffectual Lord Rosebery. He led the party to a heavy defeat in the 1895 general election.
=== Han dynasty === The Yellow Emperor's Inner Canon (Huangdi Neijing), the oldest received work of Chinese medical theory, was compiled during the Han dynasty around the first century BCE on the basis of shorter texts from different medical lineages. Written in the form of dialogues between the legendary Yellow Emperor and his ministers, it offers explanations on the relation between humans, their environment, and the cosmos, on the contents of the body, on human vitality and pathology, on the symptoms of illness, and on how to make diagnostic and therapeutic decisions in light of all these factors. Unlike earlier texts like Recipes for Fifty-Two Ailments, which was excavated in the 1970s from the Mawangdui tomb that had been sealed in 168 BCE, the Inner Canon rejected the influence of spirits and the use of magic. It was also one of the first books in which the cosmological doctrines of Yinyang and the Five Phases were brought to a mature synthesis. The Treatise on Cold Damage Disorders and Miscellaneous Illnesses (Shang Han Lun) was collated by Zhang Zhongjing sometime between 196 and 220 CE; at the end of the Han dynasty. Focusing on drug prescriptions rather than acupuncture, it was the first medical work to combine Yinyang and the Five Phases with drug therapy. This formulary was also the earliest public Chinese medical text to group symptoms into clinically useful "patterns" (zheng 證) that could serve as targets for therapy.
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.
Reverse-phase HPLC is the usual method and gives a percentage purity value. Mass spectrometry then confirms the molecular mass. Together they provide a basic identity and purity profile for a lot.