A practical reference on Selank: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-19 and is reviewed periodically as new material appears.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
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.
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 |
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 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.
Outside the centre stands a bronze statue of Thomas, by John Doubleday. Another monument to Thomas stands in Cwmdonkin Park, one of his favourite childhood haunts, close to his birthplace. The memorial is a small rock in an enclosed garden within the park cut by and inscribed by the late sculptor Ronald Cour with the closing lines from "Fern Hill".
== Military campaigns in Syria and Jazira == Ubayd Allah fought for Marwan and his tribal allies against the Qaysi tribes led by al-Dahhak ibn Qays al-Fihri, the governor of Damascus, at the Battle of Marj Rahit in August 684. The Qays were routed and al-Dahhak killed. Ubayd Allah was put in command of Marwan's army which, during Marj Rahit, consisted of 6,000 men from a handful of loyalist tribes. According to Kennedy, Ubayd Allah "clearly intended to rebuild the Syrian army which had served Mu'awiya and Yazid I so well". In the aftermath of Marj Rahit, Ubayd Allah oversaw campaigns against rebel Qaysi tribes for Marwan and his son and successor Abd al-Malik (r. 685–705) in the Jazira. However, Marwan's forces were too little to assert Umayyad rule throughout the caliphate. Thus, Ubayd Allah expanded recruitment to include various Qaysi tribes. He placed Husayn ibn Numayr al-Sakuni of Kindah as his second-in-command, and Shurahbil ibn Dhi'l Kala' of Himyar, Adham ibn Muhriz of Bahila, Rabi'a ibn al-Mukhariq of Banu Ghani and Jabala ibn Abd Allah of Khath'am as deputy commanders. Other than Husayn ibn Numayr, all of the commanders were either Qaysi or had earlier supported al-Dahhak against Marwan. In January 685, as Ubayd Allah was in Manbij preparing for the Umayyad reconquest of Iraq, Husayn ibn Numayr defeated the pro-Alid Penitents at the Battle of Ayn al-Warda. Ubayd Allah had been promised by Marwan the governorship over all of the lands he could conquer from the Alids and Ibn al-Zubayr, and he may have been sanctioned to plunder Kufa.
=== Nutrition === In nature, mice are usually herbivores, consuming a wide range of fruit or grain. However, in laboratory studies it is usually necessary to avoid biological variation and to achieve this, laboratory mice are almost always fed only commercial pelleted mouse feed. Food intake is approximately 15 g (0.53 oz) per 100 g (3.5 oz) of body weight per day; water intake is approximately 15 ml (0.53 imp fl oz; 0.51 US fl oz) per 100 g of body weight per day.
Sources: en.wikipedia.org
Their mass-to-charge ratio is proportional to their time of flight (TOF) in the drift tube and can be calculated accordingly. Coupling ESI with capillary LC can separate peptides from protein digests, while obtaining their molecular masses at the same time. Capillary electrophoresis coupled with ESI-MS is another technique; however, it works best when analyzing small amounts of proteins.
All craniate species have a distinct skull. However, not all of them possess vertebrae. The notochord is accompanied or replaced by the vertebral column in most craniates. Which consists of a series of cylindrical, and bony or cartilaginous vertebrae and projections that link the vertebrae. And these generally have neural arches that protect the spinal cord. Hagfish have incomplete braincases and lack vertebrae. Thus, they were regarded as non-vertebrate craniates. However, the cladistic exclusion of hagfish from the vertebrates is controversial, as they may have secondarily lost their vertebral columns, making them vertebrates. Molecular phylogenetics, which uses DNA sequences to classify organisms, has generally supported the grouping of hagfish and lampreys (which have vertebrae) in a clade named Cyclostomata, suggesting that the hagfish are indeed vertebrates. Examination of fossil hagfish also supports this conclusion. Indicating that Vertebrata is the same group as Craniata, instead of the former being a subset of the latter.
The proposal also "include[d] offers to negotiate an oil agreement with the United States 'satisfactory to both nations' national security interests,' develop a joint plan 'to alleviate Iraq's economical and financial problems' and 'jointly work on the stability of the gulf.'" On 29 November 1990, the Security Council passed Resolution 678, which gave Iraq until 15 January 1991 to withdraw from Kuwait, and empowered states to use "all necessary means" to force Iraq out of Kuwait after the deadline.
Sources: en.wikipedia.org
Irregularities were also reported on election day, with the election observation platform Vote62 receiving over 5,000 reports from citizens. In Chonburi Constituency 1, a large crowd gathered on 9 February to demand a recount following allegations of irregularities, including misplaced and improperly sealed ballot boxes, power outages during vote counting, vote total discrepancies, and vote tally sheets being found in a rubbish bin. The crowd remained guarding the ballot boxes overnight awaiting a decision by the Election Commission, which after a meeting asked for two days to gather and consider evidence before determining whether there would be a recount. A similar incident of crowds gathering to ask for a recount and guarding ballot boxes also occurred in Maha Sarakham Constituency 1. Following these and similar allegations, the People's Party formally requested recounts in 18 constituencies. One of its former MPs, Wiroj Lakkhanaadisorn, filed a police report against members of the Election Commission in Chonburi. The Pheu Thai Party also urged the Election Commission to investigate and address the concerns. Korn Chatikavanij, deputy leader of the Democrat Party, criticized the Election Commission, expressing disappointment that citizens were unable to feel trust in the election process. Pirapan Salirathavibhaga, the leader of the United Thai Nation Party, posted on his Facebook account demanding a nationwide recount.
Immobilized metal ion affinity chromatography (IMAC) is based on the specific coordinate covalent bond of amino acids, particularly histidine, to metals. This technique works by allowing proteins with an affinity for metal ions to be retained in a column containing immobilized metal ions, such as cobalt, nickel, or copper for the purification of histidine-containing proteins or peptides, iron, zinc or gallium for the purification of phosphorylated proteins or peptides. Many naturally occurring proteins do not have an affinity for metal ions, therefore recombinant DNA technology can be used to introduce such a protein tag into the relevant gene. Methods used to elute the protein of interest include changing the pH, or adding a competitive molecule, such as imidazole.
The expression of genes is influenced by how the DNA is packaged in chromosomes, in a structure called chromatin. Base modifications can be involved in packaging, with regions that have low or no gene expression usually containing high levels of methylation of cytosine bases. DNA packaging and its influence on gene expression can also occur by covalent modifications of the histone protein core around which DNA is wrapped in the chromatin structure or else by remodeling carried out by chromatin remodeling complexes (see Chromatin remodeling). There is, further, crosstalk between DNA methylation and histone modification, so they can coordinately affect chromatin and gene expression. For one example, cytosine methylation produces 5-methylcytosine, which is important for X-inactivation of chromosomes. The average level of methylation varies between organisms—the worm Caenorhabditis elegans lacks cytosine methylation, while vertebrates have higher levels, with up to 1% of their DNA containing 5-methylcytosine. Despite the importance of 5-methylcytosine, it can deaminate to leave a thymine base, so methylated cytosines are particularly prone to mutations. Other base modifications include adenine methylation in bacteria, the presence of 5-hydroxymethylcytosine in the brain, and the glycosylation of uracil to produce the "J-base" in kinetoplastids.
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.