heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-05-20. Anything still debated is marked as such rather than presented as settled.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, written TKPRPGP in one-letter notation. Its structure consists of the immunomodulatory tetrapeptide tuftsin, Thr-Lys-Pro-Arg, extended at the carboxyl terminus by a Pro-Gly-Pro segment. The molecular formula is commonly given as C33H57N11O9, corresponding to a monoisotopic mass near 751.4 Da and an average molecular mass near 751.9 Da. All seven residues are proteinogenic amino acids, and the molecule carries no modified side chains or non-natural linkages.
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.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
| 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 |
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
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.
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.
Quality assessment of Selank samples typically combines purity determination with identity confirmation and counter-ion analysis. Purity is usually reported as a percentage by chromatographic area, with values above 95 percent often quoted for research-grade material. Water content and residual solvents are checked in lyophilized batches because they affect both stability and accurate mass determination. A reported purity figure does not by itself establish that a sample is the intended sequence, so orthogonal methods are needed to rule out sequence isomers or truncation products.
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.
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.
=== Off-label uses === In 2012, pharmaceutical company Abbott paid $1.6 billion in fines to US federal and state governments for illegal promotion of off-label uses for Depakote, including the sedation of elderly nursing home residents. Some studies have suggested that valproate may reopen the critical period for learning absolute pitch and possibly other skills such as language.
=== Energy === In July 2018, Minister Rickford tabled Bill 2: Urgent Priorities Act, which received Royal Assent in the same month. The first session of the 42nd Legislature was on July 11 and Bill 2, which passed into law on July 25, was the Ford Government's first piece of legislation. Bill 2—an omnibus bill—was "criticized by both "business groups and unions". It legislated an end to the strike between York University and Canadian Union of Public Employees (CUPE), cancelled the White Pines Wind Project wind farm contract, and gave Ontario government "veto power over compensation at Hydro One." In December 2025, Ford and New York governor Kathy Hochul signed a memorandum of understanding which makes the New York Power Authority and Ontario Power Generation work together on advancing nuclear energy technology. In July 2026, Ford and Alberta premier Danielle Smith proposed an oil pipeline from Alberta to Sarnia, Ontario.
=== Bleaching === About 60% of the world's production of hydrogen peroxide is used for pulp- and paper-bleaching. The second major industrial application is the manufacture of sodium percarbonate and sodium perborate, which are used as mild bleaches in laundry detergents. A representative conversion is:
== Findings == In February 2021, after conducting part of their study, the WHO stated that the likely origin of COVID-19 was a zoonotic event from a virus circulating in bats, likely through another animal carrier, and that the time of transmission to humans was likely towards the end of 2019. The Chinese and the international experts who jointly carried out the WHO-convened study consider it "extremely unlikely" that COVID-19 leaked from a lab. No evidence of a lab leak from the Wuhan Institute of Virology was found by the WHO team, with team leader Peter Ben Embarek stating that it was "very unlikely" due to the safety protocols in place. During a 60 Minutes interview with Lesley Stahl, Peter Daszak, a member of the WHO team, described the investigation process to be a series of questions and answers between the WHO team and the Wuhan lab staff. Stahl made the comment that the team was "just taking their word for it", to which Daszak replied, "Well, what else can we do? There's a limit to what you can do and we went right up to that limit. We asked them tough questions. They weren't vetted in advance. And the answers they gave, we found to be believable—correct and convincing." The investigation also stated that transfer from animals to humans was unlikely to have occurred at the Huanan Seafood Market, since infections without a known epidemiological link were confirmed before the outbreak around the market.
Sources: en.wikipedia.org
Materials and samples from the original experiments remained in 2017 under the care of Miller's former student, Jeffrey Bada, a professor at the UCSD, Scripps Institution of Oceanography who also conducts origin of life research. As of 2013, the apparatus used to conduct the experiment was on display at the Denver Museum of Nature and Science.
== Personal life == In August 2009, it was reported that Lovett-Murray's home had been raided by police on 3 August. He was charged with possession of a drug of dependency, after the search found a single tablet of ecstasy at his home. However, on 11 December it was reported that the drug charge against him had been dismissed. On 22 May 2013, he was stabbed in a domestic incident by a girl's boyfriend and hospitalised. Lovett-Murray belongs to a sporting family and is the great-grandson of pastor Sir Douglas Nicholls, who played for Fitzroy Football Club. In addition, he is the cousin of former Essendon Football Club player Andrew Lovett.
==== Non-selective ==== α-MSH β-MSH γ-MSH ACTH Afamelanotide Bremelanotide Melanotan II Modimelanotide Setmelanotide — MC4 receptor agonist which is FDA approved to help with chronic weight management in those with pathogenic (or uncertain) variants in POMC and certain related genes.
Dairy farming based on the Amul Pattern, with a single marketing cooperative, is India's largest self-sustaining industry and its largest rural employment provider. Implementation of the Amul model has made India the world's largest milk producer. Here small, marginal farmers with a couple or so heads of milch cattle queue up twice daily to pour milk from their small containers into the village union collection points. The milk after processing at the district unions is then marketed by the state cooperative federation nationally under the Amul brand name, India's largest food brand. With the Anand pattern three-fourths of the price paid by the mainly urban consumers goes into the hands of millions of small dairy farmers, who are the owners of the brand and the cooperative. The cooperative hires professionals for their expertise and skills and uses hi-tech research labs and modern processing plants and transport cold-chains, to ensure quality of their produce and value-add to the milk.
It was replaced in 1996 with a tan outer bag that was better suited for service in the deserts of the Middle East. By 2000, a bean burrito main dish was introduced. In 2006, "Beverage Bags" were introduced to the MRE, as service members have begun to depend more on hydration packs than on canteens, thus denying them the use of the metal canteen cups (shaped to fit in a canteen pouch with the canteen) for mixing powdered beverages. In addition to having measuring marks to indicate levels of liquid for precise measurement, they can be sealed and placed inside the flameless heater. Most recently, MREs have been developed using the Dietary Reference Intake, created by the Institute of Medicine (IOM). The IOM indicated service members (who were classified as highly active men between the ages of 18 and 30) typically burn about 4,200 Calories (kcal) a day, but tended to only consume about 2,400 Calories a day during combat, entering a negative energy balance. This imbalance occurs when service members fail to consume full portions of their rations. Although manipulations to the food items and distribution of macronutrients to help boost the amount of kilocalories per MRE have been made, more studies are showing many service members still do not meet today's standards of daily consumption, often trading and discarding portions of the ration. Researchers continue to study the habits and eating preferences of service members, making constant changes that encourage service members to eat the entire meal and thus get full nutritional value.
Sources: en.wikipedia.org
==== Complex II ==== In Complex II (succinate dehydrogenase or succinate-CoQ reductase; EC 1.3.5.1) additional electrons are delivered into the quinone pool (Q) originating from succinate and transferred (via flavin adenine dinucleotide (FAD)) to Q. Complex II consists of four protein subunits: succinate dehydrogenase (SDHA); succinate dehydrogenase [ubiquinone] iron–sulfur subunit mitochondrial (SDHB); succinate dehydrogenase complex subunit C (SDHC); and succinate dehydrogenase complex subunit D (SDHD). Other electron donors (e.g., fatty acids and glycerol 3-phosphate) also direct electrons into Q (via FAD). Complex II is a parallel electron transport pathway to Complex I, but unlike Complex I, no protons are transported to the intermembrane space in this pathway. Therefore, the pathway through Complex II contributes less energy to the overall electron transport chain process.
In contrast to MRI, structural biology studies do not directly generate an image, but rely on complex computer calculations to generate three-dimensional molecular models. Currently most samples are examined in a solution in water, but methods are being developed to also work with solid samples. Data collection relies on placing the sample inside a powerful magnet, sending radio frequency signals through the sample, and measuring the absorption of those signals. Depending on the environment of atoms within the protein, the nuclei of individual atoms will absorb different frequencies of radio signals. Furthermore, the absorption signals of different nuclei may be perturbed by adjacent nuclei. This information can be used to determine the distance between nuclei. These distances in turn can be used to determine the overall structure of the protein. A typical study might involve how two proteins interact with each other, possibly with a view to developing small molecules that can be used to probe the normal biology of the interaction ("chemical biology") or to provide possible leads for pharmaceutical use (drug development). Frequently, the interacting pair of proteins may have been identified by studies of human genetics, indicating the interaction can be disrupted by unfavorable mutations, or they may play a key role in the normal biology of a "model" organism like the fruit fly, yeast, the worm C. elegans, or mice. To prepare a sample, methods of molecular biology are typically used to make quantities of protein by recombinant expression and purification from bacteria.
== Preservation and diagenesis == Steroids are often preserved in petroleum as saturated and aromatic steroidal hydrocarbons that result from transformations occurring during diagenesis. After senescence of steroids from aquatic producers, they undergo rapid re-mineralization under aerobic conditions in the upper water column. A small percentage of the intact sterols produced in the euphotic zone endure diagenesis, where microbial mediated transformations effectively yield compounds that can then be related back to their parent sterols and are more stable in the geologic record. The preservation of sterols is often limited, but is enhanced by anaerobic conditions during their deposition and subsequent diagenesis, in particular, early sulfurization and reduction mediated by sulfur species. Intact dinosterol has been reported from sediments of the presumed late Jurassic age, possibly due to incomplete degradation of lipids in the water column under high productivity conditions in the presence of sulfate reducers. These transformations are controlled by microbial activity and low temperature physiochemical reactions. Thermodynamically driven abiotic physicochemical reactions further alter the steroids by causing complete aromatization, isomerization and cracking of the steroids. These more stable compounds co-exist with their precursor sterols and their intermediate diagenetic products can only occur in immature sediments when incomplete microbial degradation has occurred.
Director, Yorkshire Arboretum. For services to Tree Health and Plant Conservation. Liam Daniel Hackett. Founder and Chief Executive Officer, Ditch the Label. For services to Young People. Elizabeth Hall. Founder, The Hygiene Bank. For services to Tackling Hygiene Poverty. Penelope Evelyn Hall (Penelope Gravill). Speech and Language Therapist, Aberdeen Royal Infirmary. For services to the Treatment of Skull Base Tumours and Facial Palsies. Zahid Hamid. Lately Member, Peak District National Park Authority. For services to National Parks. Dr. Simon Leslie Hancock. Councillor, Pembrokeshire County Council. For services to the community in Pembrokeshire. Adam Peter Ritchie Handling. Chef, Ambassador of The GREAT Britain and Northern Ireland Campaign. For services to Hospitality and International Trade. Richard Heafield Harris. Fintech Innovator and Entrepreneur, Ensygnia (Onescan). For services to Fintech Innovation and to Global Technological Advancement. Valda Harris (Valda Jackson). Artist. For services to Art. Lesley Ann Hastings. For services to the community in Leeds, West Yorkshire. Philip Hugh Michael Haughton. Founder, Better Food. For services to Sustainable Food Initiatives and to the community in Bristol. Elizabeth Ann Hawkins. For services to Young People and to the community in Wirral, Merseyside. Lauren May Hemp. Footballer. For services to Association Football. Alasdair Cunningham Hendry. Senior Operations Manager, Forestry Commission. For services to Forestry and to Climate Change Mitigation. Alice Maria Hendy. Founder, R;pple Suicide Prevention Charity.
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.
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.