Everything below concerns peptide stability. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-12-05. Numbers and descriptions here follow the published literature rather than marketing material.
Development took place at the Institute of Molecular Genetics of the Russian Academy of Sciences, where a series of short peptides were designed in the 1980s and 1990s. Selank was selected from variants of tuftsin that showed resistance to plasma peptidases. Russian regulatory approval covers it as an anxiolytic agent given intranasally. Outside that market the compound is normally handled as a research chemical rather than a medicine, and no widely recognised international pharmacopoeial monograph exists. The name Selank is a coined trade designation rather than a systematic chemical name.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
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 with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro, frequently abbreviated as TKPRPGP. It was designed as a structural analogue of tuftsin, a naturally occurring tetrapeptide released by enzymatic cleavage of the immunoglobulin heavy chain. The two additional proline residues at the C-terminal end extend the parent chain and change how the molecule behaves in solution. The free peptide has a calculated molecular mass of approximately 751.9 g/mol and is generally supplied as a lyophilised white to off-white powder.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue with a C-terminal Pro-Gly-Pro tail |
| Amino acid sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Abbreviated TKPRPGP in most catalogues |
| Molecular mass | About 752 Da | Value for the free peptide |
| Solubility | Freely soluble in water | Aqueous solutions are kept cold and used promptly |
| Typical storage | -20 °C, dry, protected from light | Applies to the lyophilised powder before reconstitution |
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.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
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.
=== General biochemical work === Redfield continued to develop new techniques to study the structure of protein molecules in solution, looking at cancer cells with NMR, the shell of the SARS virus cell and at amino acids. Later, using multiple resonances via shuttle and specially prepared samples, he investigated molecular activity in phospholipid vesicles.
=== EC 1.6.5 With a quinone or similar compound as acceptor === EC 1.6.5.1: deleted EC 1.6.5.2: NAD(P)H dehydrogenase (quinone) EC 1.6.5.3: now EC 7.1.1.2 NADH:ubiquinone reductase (H+-translocating) EC 1.6.5.4: monodehydroascorbate reductase (NADH) EC 1.6.5.5: NADPH:quinone reductase EC 1.6.5.6: p-benzoquinone reductase (NADPH) EC 1.6.5.7: 2-hydroxy-1,4-benzoquinone reductase EC 1.6.5.8: Now EC 7.2.1.1, NADH:ubiquinone reductase (Na+-transporting) EC 1.6.5.9: NADH:ubiquinone reductase (non-electrogenic) EC 1.6.5.10: NADPH dehydrogenase (quinone) EC 1.6.5.11: Identical to EC 1.6.5.9, NADH:quinone reductase (non-electrogenic) EC 1.6.5.12: demethylphylloquinone reductase
The Melbourne, Australia inner-city suburbs of Richmond and Abbotsford are locations in which the use and dealing of heroin has been concentrated for a protracted time period. Research organisation the Burnet Institute completed the 2013 'North Richmond Public Injecting Impact Study' in collaboration with the Yarra Drug and Health Forum, City of Yarra and North Richmond Community Health Centre and recommended 24-hour access to sterile injecting equipment due to the ongoing "widespread, frequent and highly visible" nature of illicit drug use in the areas. During the period between 2010 and 2012 a four-fold increase in the levels of inappropriately discarded injecting equipment was documented for the two suburbs. In the local government area the City of Yarra, of which Richmond and Abbotsford are parts of, 1550 syringes were collected each month from public syringe disposal bins in 2012. Furthermore, ambulance callouts for heroin overdoses were 1.5 times higher than for other Melbourne areas in the period between 2011 and 2012 (a total of 336 overdoses), and drug-related arrests in North Richmond were also three times higher than the state average. The Burnet Institute's researchers interviewed health workers, residents and local traders, in addition to observing the drug scene in the most frequented North Richmond public injecting locations.
== Distribution and habitat == Sun anemones are marine organisms that are distributed in shallow areas of the sea floor, typically at depths from 1–10 m. This species is epibenthic. Commonly called the Caribbean Sun Anemone, S. helianthus are predominantly found in the Caribbean and Western Atlantic Seas. Additionally, they have been discovered along the coast of the United States, Canada, Costa Rica and Belize. S. helianthus may live singularly, but commonly live in dense aggregations such as in reef formations.
== Community hierarchy == Like most other Sufi orders, Bektashism is initiatic, and members must traverse various levels or ranks as they progress along the spiritual path to the Reality. The Turkish names are given below, followed by their Arabic and Albanian equivalents.
Sources: en.wikipedia.org
Cushing also stated that Eddy was "a very interesting patient" who was "one of the most sensitive to the effects" of the morphine that he ever saw, and that to his surprise, the dose put her "sound asleep." Her husband Daniel Patterson was out of town at the time, but she was attended to by friends, Carrie Millett and Mary Wheeler, who took turns watching by her bedside. They told neighbors that Eddy had broken her back, was paralyzed, and possibly close to death; and at some point a call was made for a minister to come. After that Friday, Eddy apparently refused to take any more of his medicine, having lost her faith in homeopathy. On Sunday, February 4, she sent everyone out of the room and, according to her own account, she opened her Bible and read. She later wrote: "As I read, the healing Truth dawned upon my sense; and the result was that I rose, dressed myself, and ever after was in better health than I had before enjoyed." By eyewitness affidavit accounts, she then got out of bed, got dressed, and walked downstairs to the parlor to meet with her surprised and concerned friends who were gathered there with the minister. Eddy called this "the falling apple that led [her] to the discovery" of Christian Science, but she said that she did not understand it at first, and that she spent three years afterwards studying the Bible in order to understand better how she had been healed. Although Cushing had not visited Eddy on that Sunday, on Monday Cushing visited her again to check up.
== References == Pathology Outline, Fallopian Tubes Ogawa K, Johansson SL, Cohen SM (October 1999). "Immunohistochemical analysis of uroplakins, urothelial specific proteins, in ovarian Brenner tumors, normal tissues, and benign and neoplastic lesions of the female genital tract". Am. J. Pathol. 155 (4): 1047–50. doi:10.1016/S0002-9440(10)65206-6. PMC 1867018. PMID 10514386. Wrong Diagnosis.com, Brenner tumors
=== First events === When sickle cell disease presents within the first year of life, the most common problem is an episode of pain and swelling in the child's hands and feet, known as dactylitis or "hand-foot syndrome". Pallor, jaundice, and fatigue can also be early signs due to anaemia resulting from sickle cell disease. In children older than 2 years, the most common initial presentation is a painful episode of a generalised or variable nature, while a slightly less common presentation involves acute chest pain. Dactylitis is rare or almost never occurs in children over the age of 2.
Protein digestibility-corrected amino acid score (PDCAAS) is a method of evaluating the quality of a protein based on both the amino acid requirements of humans and their ability to digest it. The PDCAAS rating was recommended by the Food and Agriculture Organization of the United Nations/World Health Organization (FAO/WHO) in 1989 (report published in 1991). It was adopted by the US FDA in 1993 as "the preferred 'best'" method to determine protein quality. In 2013, FAO proposed changing to Digestible Indispensable Amino Acid Score.
As early as 520 BCE, Jain philosophy, a non-creationist philosophy based on the teachings of Mahavira, stated that the universe and its constituents such as matter cannot be destroyed or created. The Jain text Tattvarthasutra (2nd century CE) states that a substance is permanent, but its modes are characterised by creation and destruction. An important idea in ancient Greek philosophy was that "Nothing comes from nothing", so that what exists now has always existed: no new matter can come into existence where there was none before. An explicit statement of this, along with the further principle that nothing can pass away into nothing, is found in Empedocles (c. 4th century BCE): "For it is impossible for anything to come to be from what is not, and it cannot be brought about or heard of that what is should be utterly destroyed." A further principle of conservation was stated by Epicurus around the 3rd century BCE, who wrote in describing the nature of the Universe that "the totality of things was always such as it is now, and always will be".
Sources: en.wikipedia.org
Canada's judiciary interprets laws and has the power to strike down acts of Parliament that violate the constitution. The Supreme Court of Canada is the highest court, final arbiter, and has been led since 2017 by Richard Wagner, the Chief Justice of Canada. The governor general appoints the court's nine members on the advice of the prime minister and minister of justice. The federal Cabinet also appoints justices to superior courts in the provincial and territorial jurisdictions. Common law prevails everywhere except Quebec, where civil law predominates. Criminal law is solely a federal responsibility and is uniform throughout Canada. Law enforcement, including criminal courts, is officially a provincial responsibility, conducted by provincial and municipal police forces. In most rural and some urban areas, policing responsibilities are contracted to the federal Royal Canadian Mounted Police. Canadian Aboriginal law provides certain constitutionally recognized rights to land and traditional practices for Indigenous groups in Canada. Various treaties and case laws were established to mediate relations between Europeans and many Indigenous peoples. The role of Aboriginal law and the rights they support were reaffirmed by section 35 of the Constitution Act, 1982. These rights may include provision of services, such as healthcare through the Indian Health Transfer Policy, and exemption from taxation.
Analgesics (also known as "painkillers") are used to relieve pain (achieve analgesia). The word analgesic derives from Greek "αν-" (an-, "without") and "άλγος" (álgos, "pain"). Analgesic drugs act in various ways on the peripheral and central nervous systems; they include paracetamol (also known in the US as acetaminophen), the nonsteroidal anti-inflammatory drugs (NSAIDs) such as the salicylates (e.g. aspirin), and opioid drugs such as hydrocodone, codeine, heroin and oxycodone. Some further examples of the brand name prescription opiates and opioid analgesics that may be used recreationally include Vicodin, Lortab, Norco (hydrocodone), Avinza, Kapanol (morphine), Opana, Paramorphan (oxymorphone), Dilaudid, Palladone (hydromorphone), and OxyContin (oxycodone).
=== Chemical dating/ Total Pb dating === Chemical dating requires measuring the elemental abundances of U, Th and Pb but not isotopes. U-Th-total Pb dating, also known as electron microprobe U–Th–Pb dating, measures the elemental abundances of the three elements by an electron microprobe, and calculates the age (t) by the below equation.
=== Physiologically based Pharmacokinetics === Physiologically-Based Pharmacokinetic models integrate physiological information to simulate drug behavior in various tissues and organs. These models consider organ-specific blood flow, tissue permeability, and drug properties, facilitating predictions of drug concentration at specific sites. PBPK models are instrumental in understanding complex drug behaviors.
=== Scalding === In making Cheddar (or many other hard cheeses) the curd is cut into small cubes and the temperature is raised to approximately 39 °C (102 °F) to 'scald' the curd particles. Syneresis occurs and cheese whey is expressed from the particles. The Cheddar curds and whey are often transferred from the cheese vat to a cooling table which contains screens that allow the whey to drain, but which trap the curd. The curd is cut using long, blunt knives and 'blocked' (stacked, cut and turned) by the cheesemaker to promote the release of cheese whey in a process known as 'cheddaring'. During this process the acidity of the curd increases to a desired level. The curd is then milled into ribbon shaped pieces and salt is mixed into it to arrest acid development. The salted green cheese curd is put into cheese moulds lined with cheesecloths and pressed overnight to allow the curd particles to bind together. The pressed blocks of cheese are then removed from the cheese moulds and are either bound with muslin-like cloth, or waxed or vacuum packed in plastic bags to be stored for maturation. Vacuum packing removes oxygen and prevents mould (fungal) growth during maturation, which, depending on the wanted final product, may or may not be a desirable characteristic.
Sources: en.wikipedia.org
Selank is a seven-amino-acid peptide built from the tuftsin sequence plus a Pro-Gly-Pro tail. It is produced by chemical synthesis rather than extracted from a natural source. The free peptide is usually supplied as a lyophilised powder or in an aqueous formulation.
Tuftsin is a natural tetrapeptide derived from the Fc portion of immunoglobulin G. Selank retains that tetrapeptide at its N-terminus and adds three residues to improve resistance to enzymatic breakdown. The relationship is structural, and the two molecules are not interchangeable in experimental work.
It holds a product registration in Russia for intranasal use as an anxiolytic. Registrations of that kind are not automatically accepted by regulators elsewhere. In most other countries it is treated as an unapproved substance or a research material.
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.