A practical reference on Heptapeptide: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-04-03. Anything still debated is marked as such rather than presented as settled.
The compound was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences during the 1980s and 1990s. The stated design goal was to retain the immunomodulatory and central nervous system activity attributed to tuftsin while improving resistance to enzymatic breakdown. Adding a proline-rich tail to the short parent peptide was a deliberate strategy, because proline residues restrict the conformations available to many peptidases. The same laboratory produced Semax, an ACTH fragment analog, and both compounds were developed in parallel as short, enzymatically stabilized peptides intended for intranasal use.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
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.
| Property | Value | Notes |
|---|---|---|
| Peptide sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Seven residues; tuftsin plus a Pro-Gly-Pro tail |
| Molecular formula | C33H57N11O9 | Commonly reported value for the free peptide |
| Monoisotopic mass | Roughly 751.4 Da | Average molecular mass near 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as a lyophilized solid |
| Solubility class | Freely soluble in water | Also dissolves in saline and other polar solvents |
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.
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.
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.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
=== Animal model === Research into malignant hyperthermia was limited until the discovery of "porcine stress syndrome" (PSS) in Danish Landrace and other pig breeds selected for muscling, a condition in which stressed pigs develop "pale, soft, exudative" flesh (a manifestation of the effects of malignant hyperthermia) rendering their meat less marketable at slaughter. This "awake triggering" was not observed in humans, and initially cast doubts on the value of the animal model, but subsequently, susceptible humans were discovered to "awake trigger" (develop malignant hyperthermia) in stressful situations. This supported the use of the pig model for research. Pig farmers use halothane cones in swine yards to expose piglets to halothane. Those that die were MH-susceptible, thus saving the farmer the expense of raising a pig whose meat he would not be able to market. This also reduced the use of breeding stock carrying the genes for PSS. The condition in swine is also due to a defect in ryanodine receptors. Gillard et al. discovered the causative mutation in humans only after similar mutations had first been described in pigs. Horses also develop malignant hyperthermia. A causative mutated allele, ryanodine receptor 1 gene (RyR1) at nucleotide C7360G, generating a R2454G amino acid substitution. has been identified in the American Quarter Horse and breeds with Quarter Horse ancestry, inherited as an autosomal dominant. It can be caused by overwork, anesthesia, or stress. In dogs, its inheritance is autosomal recessive.
=== Decline === By 1987, the label began to see its commercial fortunes decline. Contributing to the decline were A&R problems with Shalamar, primarily, maintaining the group's identity and momentum as former members Hewett and Watley had departed and were having successful solo careers on other labels. The shifting musical directions of R&B, dance and popular music in general in the late 1980s and early 1990s also contributed to their decline.
Glycoproteins and phosphoproteins are usually associated with covalent bonds since they have a carbohydrate or phosphate residue attached to the side chains of certain amino acid residues like asparagine, serine, and threonine. On the other hand, metalloproteins usually involve coordination bonds where there would be bonds between the metal ions and side chains of some amino acids like histidine, cysteine, or aspartic acid. All of these interactions create stable structures that are important for protein function. It is common for the prosthetic group to contribute to the function of the protein. An example of this is if the prosthetic group is broken away from the protein, the function of that protein is lost. This is seen in hemoglobin. When the heme group of hemoglobin is removed, the function of the protein is lost, making it a nonfunctional protein. This all highlights the prosthetic groups importance in maintaining both the structure and protein activity of conjugated proteins.
During the time leading up to the passing of the laws, there was fierce opposition to them, above all by the Free Democratic Party, the rising West German student movement, a group calling itself Notstand der Demokratie ("Democracy in Crisis") and members of the Campaign against Nuclear Armament. A key event in the development of open democratic debate occurred in 1967, when the Shah of Iran, Mohammad Reza Pahlavi, visited West Berlin. Several thousand demonstrators gathered outside the Opera House where he was to attend a special performance. Supporters of the Shah (later known as Jubelperser), armed with staves and bricks attacked the protesters while the police stood by and watched. A demonstration in the centre was being forcibly dispersed when a bystander named Benno Ohnesorg was shot in the head and killed by a plainclothes policeman. (It has now been established that the policeman, Kurras, was a paid spy of the East German security forces.) Protest demonstrations continued, and calls for more active opposition by some groups of students were made. In a massive campaign against the protesters, the press, especially the tabloid Bild-Zeitung newspaper, described these as a massive disruption to life in Berlin. Protests against the US intervention in Vietnam, mingled with anger over the vigour with which demonstrations were repressed led to mounting militance among the students at the universities in Berlin.
Euchambersia, an extinct genus of therocephalians, is hypothesized to have had venom glands attached to its canine teeth. A few species of living mammals are venomous, including solenodons, shrews, the European mole, vampire bats, male platypuses, and slow lorises. Shrews have venomous saliva and most likely evolved their trait similarly to snakes. The presence of tarsal spurs akin to those of the platypus in many non-therian Mammaliaformes groups suggests that venom was an ancestral characteristic among mammals. Extensive research on platypuses shows that their toxin was initially formed from gene duplication, but data provides evidence that the further evolution of platypus venom does not rely as much on gene duplication as was once thought. Modified sweat glands are what evolved into platypus venom glands. Although it is proven that reptile and platypus venom have independently evolved, it is thought that there are certain protein structures that are favored to evolve into toxic molecules. This provides more evidence of why venom has become a homoplastic trait and why very different animals have convergently evolved.
Sources: en.wikipedia.org
The ability of birds to return to precise locations across vast distances has been known for some time; in an experiment conducted in the 1950s, a Manx shearwater released in Boston in the United States returned to its colony in Skomer, in Wales within 13 days, a distance of 5,150 km (3,200 mi). Birds navigate during migration using a variety of methods. For diurnal migrants, the sun is used to navigate by day, and a stellar compass is used at night. Birds that use the sun compensate for the changing position of the sun during the day by the use of an internal clock. Orientation with the stellar compass depends on the position of the constellations surrounding Polaris. These are backed up in some species by their ability to sense the Earth's geomagnetism through specialised photoreceptors.
Flavoproteins are proteins that contain a nucleic acid derivative of riboflavin. These proteins are involved in a wide array of biological processes, including removal of radicals contributing to oxidative stress, photosynthesis, and DNA repair. The flavoproteins are some of the most-studied families of enzymes. Flavoproteins have either FMN (flavin mononucleotide) or FAD (flavin adenine dinucleotide) as a prosthetic group or as a cofactor. The flavin is generally tightly bound (as in adrenodoxin reductase, wherein the FAD is buried deeply). About 5-10% of flavoproteins have a covalently linked FAD. Based on the available structural data, FAD-binding sites can be divided into more than 200 different types. 90 flavoproteins are encoded in the human genome; about 84% require FAD and around 16% require FMN, whereas 5 proteins require both. Flavoproteins are mainly located in the mitochondria. Of all flavoproteins, 90% perform redox reactions and the other 10% are transferases, lyases, isomerases, ligases.
== Business and philanthropy career == Pritzker co-founded Pritzker Group Private Capital with his brother Anthony Pritzker, serving as managing partner before stepping down in 2017 to run for governor. Anthony Pritzker reported that the Pritzker Group generated a return of 28.7% from 2007 to 2012, focusing on investing in family businesses and other entrepreneurial enterprises. In 2008, he received the Chicagoland Chamber of Commerce's Entrepreneurial Champion Award for his efforts to promote economic development and job creation. Pritzker served as chairman of ChicagoNEXT, then-Chicago Mayor Rahm Emanuel's Council on Innovation and Technology, and founded 1871, a nonprofit digital startup incubator, which, as of February 2025, had created 15,000 jobs and raised $4 billion in venture capital, according to a memo by its CEO, Betsy Ziegler. He was involved in the creation of the Illinois Venture Capital Association and the Chicagoland Entrepreneurial Center. He also co-founded Chicago Ventures and funded the startups Techstars Chicago and Built in Chicago. Pritzker is a member of the Illinois State Bar Association and the Chicago Bar Association. He has also been active in philanthropy. The J.B. and M.K. Pritzker Family Foundation, founded in 2001, has given millions of dollars to numerous causes, particularly early-childhood education. Most notably, in 2015, the foundation gave $100 million to the Northwestern Law School, which was renamed the Pritzker Law School.
The council is based at County Hall at Aykley Heads in the northern suburbs of the city of Durham. The building was purpose-built for the council and was completed in 1963. When first created the council met at the courthouse on Old Elvet, which at the time was known as Shire Hall. A few years after its creation the council decided to build its own headquarters on a site nearby, also on Old Elvet, which was also given the name Shire Hall. The new building was completed in 1898, after which the old Shire Hall became known as the Assizes Court, and since 1971 as Durham Crown Court. The council has announced plans to move to the Rivergreen building, also in the Aykley Heads area of Durham, in 2025, with the intention that County Hall would then be redeveloped.
Guillermo Uribe Holguín, an important cultural figure in the National Symphony Orchestra of Colombia, Luis Antonio Calvo and Blas Emilio Atehortúa are some of the greatest exponents of the art music. The Bogotá Philharmonic Orchestra is one of the most active orchestras in Colombia. Caribbean music has many vibrant rhythms, such as cumbia (it is played by the maracas, the drums, the gaitas and guacharaca), porro (it is a monotonous but joyful rhythm), mapalé (with its fast rhythm and constant clapping) and the "vallenato", which originated in the northern part of the Caribbean coast (the rhythm is mainly played by the caja, the guacharaca, and accordion). The music from the Pacific coast, such as the currulao, is characterized by its strong use of drums (instruments such as the native marimba, the conunos, the bass drum, the side drum, and the cuatro guasas or tubular rattle). An important rhythm of the south region of the Pacific coast is the contradanza (it is used in dance shows due to the striking colours of the costumes). Marimba music, traditional chants and dances from the Colombia South Pacific region are on UNESCO's Representative List of the Intangible Cultural Heritage of Humanity.
Sources: en.wikipedia.org
Ozarelix (developmental code names D-63153, SPI-153) is a peptide gonadotropin-releasing hormone antagonist (GnRH antagonist) which is or was under development by AEterna Zentaris Inc. and Spectrum Pharmaceuticals as a long-acting injection formulation for the treatment of prostate cancer. It has also been investigated for the treatment of endometriosis, but no development has been reported. The drug was previously under investigation for the treatment of benign prostatic hyperplasia and Alzheimer's disease as well, but development for these indications was discontinued. As of June 2015, it was in phase II clinical trials for prostate cancer. It seems to no longer be under development.
=== 1970: In the Wake of Poseidon and Lizard === King Crimson spent 1970 in a state of flux with various line-up changes, thwarted tour plans, and difficulties in finding a satisfactory musical direction, while Fripp was learning and developing as a songwriter during the writing process of the next three albums. As well as guitar, Fripp took on keyboard duties, while Sinfield expanded his creative role to operating synthesizers. Following McDonald's and Giles's departure, Lake, unsure of the band's future without them, began discussions with Keith Emerson of the Nice about possibly forming a new band together. With Fripp and Sinfield planning the recording of the second King Crimson album, and Lake's position uncertain, the band's management booked Elton John to sing on the album, a decision cancelled by Fripp after he listened to John's then-only album, Empty Sky, and deemed his singing style to be not right for King Crimson. Lake agreed to stay with the band until Emerson had completed remaining commitments with the Nice, at which point he left to form Emerson, Lake & Palmer with Emerson and Carl Palmer of Atomic Rooster. On the resulting In the Wake of Poseidon album, Lake provided all the lead vocals except on "Cadence and Cascade", which featured Fripp's old school friend Gordon Haskell. The sessions also included Michael and Peter Giles on drums and bass respectively, saxophonist Mel Collins (formerly of the band Circus), and jazz pianist Keith Tippett. Upon its release in May 1970, In the Wake of Poseidon reached No. 4 in the UK and No. 31 in the US.
=== Fraud === Tea is a common target of food fraud. Lower cost ingredients may be substituted for tea, or a tea may be adulterated with undeclared and possibly toxic colors and flavours. The origin of the tea, picking season, and the processing techniques may be intentionally misidentified. Tea powders which undergo additional processing are more susceptible to food fraud.
Felinine, also known as (R)-2-amino-3-(4-hydroxy-2-methylbutan-2-ylthio)propanoic acid, is an amino acid found in cat urine and a precursor via microbial lyase of the putative cat pheromone and thiol called 3-mercapto-3-methylbutan-1-ol (MMB).
Sources: en.wikipedia.org
The sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter code. It combines the tetrapeptide tuftsin with a carboxyl-terminal Pro-Gly-Pro extension. This full sequence identifies the molecule more precisely than the research name.
No peptide with this exact sequence has been identified as an endogenous substance. It is a laboratory-designed analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The Pro-Gly-Pro extension has no known natural source.
Proline introduces conformational constraints that make a peptide less accessible to common peptidases. This is a standard stabilization strategy in peptide design. The added residues also increase the distance between the active tuftsin portion and typical cleavage sites.
Identity is confirmed by matching the retention time in reversed-phase chromatography against a reference standard and by measuring the molecular mass with mass spectrometry. Tandem mass spectrometry or amino acid analysis can verify the sequence of the seven residues. Because the peptide contains no aromatic amino acids, detection at 280 nm is not useful.