If you have been reading about Heptapeptide and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-07-14. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | Tuftsin analogue |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Calculated for the free peptide |
| Molecular weight | About 751.9 g/mol | Derived from the sequence |
| Appearance | White to off-white powder | Typical lyophilised form |
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.
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.
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.
Other methods that determine water content of a sample include chemical titrations (for example the Karl Fischer titration), determining mass loss on heating (perhaps in the presence of an inert gas), or after freeze drying. In the food industry the Dean-Stark method is also commonly used. From the Annual Book of ASTM (American Society for Testing and Materials) Standards, the total evaporable moisture content in Aggregate (C 566) can be calculated with the formula:
This craze died down amid warnings of kojic acid, reports of contamination in home-made cultures, and insufficient capabilities for industrial production. In addition, Chen Jin-Shu of National Chung Hsing University noted that kombucha was briefly home-made in Taiwan under the name hóngchá gū (Chinese: 紅茶菇; from Japanese kōcha kinoko) in the 1960s.
===== Senate allegations ===== In May 2005, a United States Senate committee report accused Galloway and others of receiving, from the Iraqi government, the right to buy oil under the UN's Oil-for-Food Programme. The report was issued by the US Senate Permanent Subcommittee on Investigations, chaired by Senator Norm Coleman, a Republican from Minnesota. Coleman's committee said that Galloway received oil allocations worth 20 million barrels (3,200,000 m3) from 2000 to 2003. The allegations against Galloway, had been made before, including in an October report by US arms inspector Charles Duelfer, as well as in the various purported documents described earlier in this section.
In March 2024, the Japanese Ministry of Health ordered stores to remove three RYR dietary supplements (Benikoji ColesteHelp, NaishiHelp Plus Cholesterol and Natto-kinase Sarasara Tsubu) produced by Kobayashi Pharmaceutical after reports of thousands made ill. Over a hundred people between the ages of 40 and 80 were hospitalized, and five had died as of 29 March, with four of them from kidney problems. There have been more than twelve thousand cases of health problems reported by users. The company said it uses a strain that does not produce citrinin. It has found puberulic acid in the recalled products and is looking into whether the substance might be linked to the fatalities. The suspect batch was manufactured in 2023. Some analysts have placed the blame on industry deregulation, intended to boost economic growth by facilitating the approval of health products. Benikoji products such as miso paste, crackers, food coloring, and a vinegar dressing made by other companies were also recalled. Kobayashi Pharmaceutical officially discontinued production of beni koji products on 8 August 2024.
Sources: en.wikipedia.org
Preservation of the Church's autonomy and rights, as accepted by the constitution. Defence against any attack on the independence of Church bodies, on the development of religious life and on the practice of Christian charity. Effectual implementation of parity for recognised denominations. Rejection of any attempt to de-Christianise marriage. Preservation or founding of denominational schools. There were also more general demands such as for a more federal, decentralised state, a limitation of state expenditure, a just distribution of taxes, the financial strengthening of the middle classes and the legal "removal of such evil states, that threaten the worker with moral or bodily ruin". With such a manifesto, the number of Catholic representatives in the Prussian Diet rose considerably. In December 1870, they formed a new "Centre" faction, also called the "Constitution Party" to emphasise its adherence to constitutional liberties. Three months later, early in 1871, the Catholic representatives to the new national parliament, the Reichstag, also formed a "Centre" faction. The party not only defended the Church's liberties, but also supported representative government and minority rights in general, in particular those of German Poles, Alsatians, and Hannoverians. The Centre's main leader was the Hannoverian advocate Ludwig Windthorst and other major figures included Karl Friedrich von Savigny, Hermann von Mallinckrodt, Burghard Freiherr von Schorlemer-Alst, the brothers August Reichensperger and Peter Reichensperger, Franz von Ballestrem and Georg Count Hertling.
=== Redox === p-Hydroxybenzoate hydroxylase (PHBH) catalyzes the oxygenation of p-hydroxybenzoate (pOHB) to 3,4-dihyroxybenzoate (3,4-diOHB); FAD, NADPH and molecular oxygen are all required for this reaction. NADPH first transfers a hydride equivalent to FAD, creating FADH−, and then NADP+ dissociates from the enzyme. Reduced PHBH then reacts with molecular oxygen to form the flavin-C(4a)-hydroperoxide. The flavin hydroperoxide quickly hydroxylates pOHB, and then eliminates water to regenerate oxidized flavin. An alternative flavin-mediated oxygenation mechanism involves the use of a flavin-N(5)-oxide rather than a flavin-C(4a)-(hydro)peroxide.
It has become widely accepted in science that early in the history of life on Earth, prior to the evolution of DNA and possibly of protein-based enzymes as well, an "RNA world" existed in which RNA served as both living organisms' storage method for genetic information—a role fulfilled today by DNA, except in the case of RNA viruses—and potentially performed catalytic functions in cells—a function performed today by protein enzymes, with the notable and important exception of the ribosome, which is a ribozyme.
Sources: en.wikipedia.org
HCO2CH3 + H2O → HCOOH + CH3OH Efficient hydrolysis of methyl formate requires a large excess of water. Some routes proceed indirectly by first treating the methyl formate with ammonia to give formamide, which is then hydrolyzed with sulfuric acid:
=== Neurodegenerative diseases === AEP is activated during brain ischemia or brain acidosis and epilepsia seizure. It digests SET protein, which is an inhibitor of DNase, leading to DNA damage and causing damage of the brain. Increased activity of AEP in brain is also observed in patients with Alzheimer's disease and Parkinson's disease (PD). AEP cleaves tau protein and amyloid precursor protein. In patients with PD, alpha synuclein is cut by AEP into toxic chunks., which are hypothesized to possibly play a role in the initiation or pathogenesis of PD
== Medical uses == Patiromer is used for the treatment of hyperkalemia, but not as an emergency treatment for life-threatening hyperkalemia, as it acts relatively slowly. Such a condition needs other kinds of treatment, for example calcium infusions, insulin plus glucose infusions, salbutamol inhalation, and hemodialysis. Typical reasons for hyperkalemia are chronic kidney disease and application of drugs that inhibit the renin–angiotensin–aldosterone system (RAAS) – e.g. ACE inhibitors, angiotensin II receptor antagonists, or potassium-sparing diuretics – or that interfere with kidney function in general, such as nonsteroidal anti-inflammatory drugs (NSAIDs).
Sources: en.wikipedia.org
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.
Selank is a synthetic analogue built on the tuftsin tetrapeptide Thr-Lys-Pro-Arg. Extra proline residues were added to the C-terminus during design work. That modification is intended to make the peptide less vulnerable to rapid enzymatic degradation.
Transliteration from Russian produces variant spellings such as Selanc. Many suppliers avoid the trade-style name entirely and list the peptide sequence. Comparing sequences rather than names is the reliable way to confirm two entries describe the same molecule.
Sealed, desiccated storage at -20 °C or colder is the standard recommendation for research-grade material. Vials should reach room temperature before they are opened, which limits condensation. Repeated temperature cycling is discouraged.