This is a working overview of Tuftsin analogue, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-02-01 and is reviewed periodically as new material appears.
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.
Peptide bonds in selank are susceptible to hydrolysis under strongly acidic or basic conditions, and the terminal proline residues are vulnerable to exopeptidase activity in biological samples. Lyophilized powder stored dry at -20 °C typically remains stable for extended periods, whereas aqueous solutions degrade faster and may lose measurable purity within days to weeks depending on pH, temperature, and microbial load. Repeated freeze-thaw cycles promote aggregation and adsorption to container surfaces. For analytical work, solutions are usually prepared fresh, kept cold, and used within a single working day.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Identity confirmation | Reversed-phase HPLC retention time versus reference standard | Retention depends on column, gradient, and ion-pairing agent |
| Mass confirmation | Electrospray or MALDI mass spectrometry | Doubly protonated ion near m/z 377 is consistent with about 752 Da |
| Typical purity specification | 95 percent or higher by chromatographic peak area | Lower values suggest truncated or modified peptide species |
| Storage of lyophilized powder | -20 °C, desiccated, protected from light | Powder tolerates long storage better than solution |
| Storage of solution | 2-8 °C for short periods | Freeze-thaw cycling promotes aggregation and surface adsorption |
Selank is a hydrophilic peptide and dissolves readily in water and in aqueous buffers. The lyophilised powder is typically a white to off-white solid. Because short peptides are prone to hydrolysis and oxidation, handling benefits from limiting exposure to heat, moisture and strong light. Working solutions are commonly prepared in sterile water or saline, and repeated freeze-thaw cycles are avoided to reduce aggregation and loss of activity. These practices reflect general laboratory convention rather than published stability specifications.
Dry powder is normally held at -20 degrees Celsius or lower, in a sealed container with desiccant and protection from light. Reconstituted solutions are usually kept at 2 to 8 degrees Celsius for short periods and frozen for longer ones. Proline residues at several positions are generally associated with some resistance to peptidase attack, but chemical stability still declines at neutral to alkaline pH and at elevated temperature. Exact shelf-life figures are product-specific and are not standardised across suppliers.
Identity and purity are usually assessed by reversed-phase high-performance liquid chromatography, with mass spectrometry used to confirm molecular mass and sequence information. Amino acid analysis and peptide mapping may supplement these methods. Certified reference standards are scarce, and many commercial lots are sold as research chemicals without a pharmacopoeial monograph. Regulatory treatment differs by country: Selank is a registered prescription medicine in Russia, while in the European Union and the United States it is not an approved drug and may fall under research-chemical or unapproved-product frameworks.
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.
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.
In the spring of 1778, a heavy chain supported by huge log rafts was stretched across the Hudson from West Point to Constitution Island to impede the movement of British ships north of West Point. A second log boom (resembling a ladder in construction) spanned the river about 100 yards (90 m) downstream to absorb the impact of any ship attempting to breach the barrier. The Hudson River's changing tides, strong current, and frequently unfavorable winds created adverse sailing conditions at West Point. Compounding this, the river's narrow width and sharp "S-Curve" there forced any large ship to tack in order to navigate it. Cannon were placed in forts and artillery batteries on both sides of the river to attack ships when they were slowed to a halt by the Patriot barrier placed there. The chain was constructed over six weeks at the Sterling Iron Works in Warwick, Orange County. The multiple forge-fire site and trip hammer was rediscovered in 2008 within Sterling Forest State Park. When completed, the 600-yard (550 m) chain contained iron links two feet (0.6 m) in length, weighing 140 to 180 pounds (64 to 82 kg). The links were carted to New Windsor, where they were put together and floated down the river to West Point on logs late in April. Including swivels, clevises, and anchors, the chain weighed 65 tons. For buoyancy, logs were cut into 16-foot (5 m) lengths, waterproofed, and joined by fours into rafts fastened to one another with 12-foot (3.7 m) timbers.
=== Growth factors for vascularization, migration, degradation, proliferation === Stroma contains extracellular matrix components such as proteoglycans and glycosaminoglycans which are highly negatively charged, largely due to sulfated regions, and bind growth factors and cytokines, acting as a reservoir of these cytokines. In tumors, cancer cells secrete matrix degrading enzymes, such as matrix metalloproteinases (MMPs) that, once cleaved and activated, degrade the matrix, thereby releasing growth factors that signal for the growth of cancer cells. MMPs also degrade ECM to provide space for vasculature to grow to the tumor, for the tumor cells to migrate, and for the tumor to continue to proliferate.
In sports, the term performance-enhancing drugs is popularly used in reference to anabolic steroids or their precursors (hence the colloquial term steroids); anti-doping organizations apply the term broadly. Agencies such as the WADA and the United States Anti-Doping Agency try to prevent athletes from using these drugs by performing drug tests. When medical exemptions are granted they are called therapeutic use exemptions.
The two substrates of this enzyme are 6-hydroxyhexanoic acid and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 6-oxohexanoic acid, reduced NADH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 6-hydroxyhexanoate:NAD+ oxidoreductase. This enzyme participates in caprolactam degradation.
Sources: en.wikipedia.org
Starmer says he has taken account of whether it would be right "to impose a further burden on the taxpayer". MSPs vote unanimously in favour of plans to ban dual mandates. Following an external review into the use of messaging services, Scotland's Deputy First Minister, Kate Forbes announces that Scottish Government ministers and staff will be banned from using WhatsApp for official business. Former First Minister of Scotland Humza Yousaf announces he will step down as an MSP at the 2026 Scottish Parliament election. Democracy and Boundary Commission Cymru unveils the names of the 16 constituencies that will make up the enlarged Senedd from 2026, with all but four of them known by exclusively Welsh language names. The Welsh Conservatives reaffirm their commitment to devolution following a social media post by MS Joel James, who said he wanted to get "rid" of the Senedd; the post, in response to the announcement of the constituencies for the 2026 election, was swiftly deleted. Nigel Farage says that Reform UK are in "open negotiations" with US billionaire Elon Musk about him donating to the party after the pair met at Donald Trump's Mar-a-Lago estate in Florida. 18 December – Reform UK confirms that Craig Campbell, a party official in Scotland, has been removed from his post after revelations his family has links to Ulster Loyalists and has a relatives who was convicted of murdering a Celtic fan. Police are called to what is described as a heated meeting of Oldham Council.
Different isoforms of actin are present in the cell nucleus. The level of actin isoforms may change in response to stimulation of cell growth or arrest of proliferation and transcriptional activity. Research on nuclear actin is focused on isoform beta. However the use of antibodies directed against different actin isoforms allows identifying not only the cytoplasmic beta in the cell nucleus, but also alpha- and gamma-actin in certain cell types. The presence of different isoforms of actin may have a significant effect on its function in nuclear processes, as the level of individual isoforms can be controlled independently. Functions of actin in the nucleus are associated with its ability to polymerize and interact with various ABPs and with structural elements of the nucleus. Nuclear actin is involved in:
Smith was hired to become the defensive quality control coach for the Tennessee Titans in 2011 under new head coach Mike Munchak. Smith then became the offensive quality coach the following season. In 2013, Smith was promoted to the assistant offensive line and assistant tight ends coach. Munchak was fired after the 2013 season and new head coach Ken Whisenhunt retained Smith as the assistant tight ends coach. Midway through the 2015 season, Whisenhunt was fired and replaced by tight ends coach Mike Mularkey. Mularkey was kept as head coach for the 2016 season and Smith was promoted to the new tight ends coach. When Mularkey was fired after the 2017 season, new head coach Mike Vrabel kept Smith as the tight ends coach for 2018. On January 21, 2019, Smith was promoted to offensive coordinator, replacing Matt LaFleur, who departed to become head coach of the Green Bay Packers two weeks prior. In his first year as offensive coordinator, Smith oversaw the highest-scoring Titans team in 16 years, with Derrick Henry, Ryan Tannehill, and Jonnu Smith having career years. Smith was praised for his play-calling in the Titans' 28–12 road victory over the top-seeded Baltimore Ravens in the AFC Divisional Round. In 2020, the Titans ranked fourth in scoring and second in total yards.
Sources: en.wikipedia.org
Bažant (1983) proposed a crack band model for materials like concrete whose homogeneous nature changes randomly over a certain range. He also observed that in plain concrete, the size effect has a strong influence on the critical stress intensity factor, and proposed the relation
Control of petroleum production has been a significant driver of international relations during much of the 20th and 21st centuries. Organizations like OPEC have played an outsized role in international politics. Some historians and commentators have called this the "Age of Oil" With the rise of renewable energy and addressing climate change some commentators expect a realignment of international power away from petrostates.
== External links == Human CSNK1D genome location and CSNK1D gene details page in the UCSC Genome Browser. Overview of all the structural information available in the PDB for UniProt: P48730 (Human Casein kinase I isoform delta) at the PDBe-KB. Overview of all the structural information available in the PDB for UniProt: Q9DC28 (Mouse Casein kinase I isoform delta) at the PDBe-KB.
=== Cystine === Cystine is a dimer consisting of two cysteine molecules and the formation of a disulfide bond. This amino acid is a rate limiting substrate used in the SLC7A11 cystine/glutamate transporter and is usually imported into the cell. Cysteine-158 is specifically used in the formation of the disulfide bridge for the protein structure of system Xc-. There are neurotoxins, such as BMAA, that can prevent the intake of cystine, which can lead to decreased extracellular glutamate levels and an increase in oxidative stress.
Sources: en.wikipedia.org
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.
Lyophilized powder is normally stored desiccated at -20 °C, protected from light and moisture. Powder kept under these conditions is generally stable for long periods. Solutions are less stable and are usually prepared immediately before use.
A purity value from one chromatographic method does not capture every possible impurity. Related peptides with similar retention behavior, counterions, and residual solvents may not appear in the same analysis. Independent testing with an orthogonal method provides stronger assurance of identity and content.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.