HPLC comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-04-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Lyophilized selank is normally supplied as a dry powder and is considered stable for extended periods when kept cold and dry. Moisture uptake is the main practical threat, because absorbed water promotes both hydrolysis and aggregation in the solid state. Vials are usually warmed to room temperature before opening so that condensation does not form on the powder. Supplier documentation commonly specifies -20 °C for routine storage, with -80 °C used for material intended to be archived for years.
| 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 |
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.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
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.
Selank is not a naturally occurring peptide and has no known endogenous counterpart in human physiology. Russian-language sources frequently call it TP-7, while English-language sources use the name Selank almost exclusively. Database indexing is uneven, partly because early reports appeared in regional journals that are not widely cataloged. Some summaries describe the material as a tuftsin analog and others as a synthetic heptapeptide; the labels overlap rather than conflict. Citing the primary sequence resolves ambiguity more reliably than the research or trade name alone.
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.
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.
Solubility behavior is a practical concern for handling. Selank dissolves readily in water and in common aqueous buffers, which simplifies preparation of working solutions. The choice of solvent, ionic strength, and pH can influence aggregation over time, particularly at higher concentrations. Aqueous solutions are typically sterile-filtered before use. Because stability depends on several variables, storage and handling notes should be treated as general guidance rather than fixed rules, and specific values are best confirmed against a certificate of analysis for each batch.
Characterization of Selank in a laboratory setting relies on standard peptide methods. Reverse-phase high-performance liquid chromatography separates the target from related impurities and provides a purity figure, commonly reported as 95 percent or higher. Mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, confirms the molecular mass and helps detect truncation or modification. Amino acid analysis can verify composition when a sequence-level check is needed. These techniques together establish identity and purity for a given lot.
=== Defunct === Liaison Committee for a Revolutionary Workers International, founded by former militants of the Argentinian MAS and PO Committee for a Workers' International (CWI), 1974–2019 – split into Committee for a Workers' International (Refounded) and International Socialist Alternative Coordinating Committee for the Refoundation of the Fourth International, CCRCI (2004-2020) International League for the Reconstruction of the Fourth International (ILRFI), 1976–1995 Workers International to Rebuild the Fourth International (WIRFI) International Revolutionary Marxist Tendency (TMRI), 1965–1992 Permanent Revolution Revolutionary Workers Ferment (Fomento Obrero Revolucionario, FOR) Trotskyist International Liaison Committee, 1979–1984 Tendencia Cuartainternacionalista Fourth International (ICR), also called FI (La Verité) or FI (International Secretariat) 1981–2015 Socialist Network (Post-Trotskyist, split from IMT) International Trotskyist Opposition] (ITO) 2022–2025 (Dissolved into LIS-ISL) League for the Fifth International (L5I), founded by expelled members of the IST. (1989-2025)
==== Autonomous republics ==== All sixteen republics under the Russian SFSR Crimean ASSR under Ukraine Karakalpak ASSR under Uzbekistan Abkhaz SSR (former ASSR under Georgia, which had declared independence)
== Reception == Since its broadcast, the series has caused heated discussions online and obtained high ratings. Shen Yan, director of the series, attribute the show's success to its capability to capture modern life in China through several ordinary people's lives and the great influence of book writer Isabel Nee Yeh-su. By emphasizing the importance of female independence, the series has won much favor among female audiences. However, the series has been criticized by book fans for veering too much from the plot. Its display of improper ethical values has also been criticized for degrading social conduct.
== External links == Pu-239 / The Half-Life of Timofey Berezin Official HBO site Pu-239 at IMDb Pu-239 at Rotten Tomatoes The Half Life of Timofey Berezin[link removed] at the TIFF 2006 archival site.
In May 2019, in a milestone effort, researchers reported the creation of a new synthetic (possibly artificial) form of viable life, a variant of the bacteria Escherichia coli, by reducing the natural number of 64 codons in the bacterial genome to 59 codons instead, in order to encode 20 amino acids. In 2017, the international Build-a-Cell large-scale open-source research collaboration for the construction of synthetic living cells was started, followed by national synthetic cell organizations in several countries, including FabriCell, MaxSynBio and BaSyC. The European synthetic cell efforts were unified in 2019 as SynCellEU initiative. In 2023, researchers were able to create the first synthetically made human embryos derived from stem cells.
Sources: en.wikipedia.org
Although the number of local news media outlets had increased in the 2000s, the Ba'ath Party continued to maintain its tight control and censorship of the press. Journalists and bloggers have been arrested and tried. In 2009, the committee to Protect Journalists named Syria number three in a list of the ten worst countries in which to be a blogger, given the arrests, harassment, and restrictions which online writers in Syria faced. Internet censorship in Ba'athist Syria was extensive. The Ba'athist government banned websites over political reasons and arrests people accessing them. Internet cafes are required to record all the comments users post on chat forums. Websites such as Wikipedia Arabic, YouTube and Facebook were blocked from 2008 to 2011. Filtering and blocking was found to be pervasive in the political and Internet tools areas, and selective in the social and conflict/security areas by the OpenNet Initiative in August 2009. Syria has been on Reporters Without Borders' Enemy of the Internet list since 2006 when the list was established. In addition to filtering a wide range of Web content, the Ba'athist Syrian government monitored Internet use very closely and detained citizens "for expressing their opinions or reporting information online." Vague and broadly worded laws invite government abuse and have prompted Internet users to engage in self-censorship to avoid the state's ambiguous grounds for arrest. The Syrian Centre for Media and Free Expression was closed by the Ba'athist government in September 2009.
The Rho family of GTPases is a family of small (~21 kDa) signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are found in all eukaryotic kingdoms, including yeasts and some plants. Three members of the family have been studied in detail: Cdc42, Rac1, and RhoA. All G proteins are "molecular switches", and Rho proteins play a role in organelle development, cytoskeletal dynamics, cell movement, and other common cellular functions.
== Preservatives == Frozen products do not require any added preservatives because microorganisms do not grow when the temperature of the food is below −9.5 °C (15 °F), which is sufficient on its own in preventing food spoilage. Long-term preservation of food may call for food storage at even lower temperatures. Carboxymethylcellulose (CMC), a tasteless and odorless stabilizer, is typically added to frozen food because it does not adulterate the quality of the product.
In a 1990 interview, Freeman said that Glory was one of his favorite releases—"The Black legacy is as noble, is as heroic, is as filled with adventure and conquest and discovery as anybody else's. It's just that nobody knows it." In 1990, Freeman provided the voice of Frederick Douglass in The Civil War, a television miniseries about the American Civil War. In the same year he played a key role in the critically panned The Bonfire of the Vanities. According to the review aggregate site Rotten Tomatoes, the film has an approval rating of 16% based on 51 reviews. In the summer of 1990, he played Petruchio, a role he had been thinking about for six years, in Shakespeare's The Taming of the Shrew, which opened at Delacorte theater in New York City. "[Petruchio] seems to have a lot of fun in life", he said. In 1991, Freeman had a supporting role in Robin Hood: Prince of Thieves, an action-adventure starring Kevin Costner. The film was a commercial success, but garnered mixed reviews from critics; The New York Times' Vincent Canby thought Freeman played Azeem with "wit and humor" despite the "muddled" plot.
== Hazards == There are hazards involved with being a diener. There are approximately six types of hazards that a diener is at risk for: mechanical, sharp force, electrical, chemical, radiation, and infection. Mechanical hazards categorize harm such as back injury from activity such as transporting cadavers. Sharp force hazards categorize any bodily harm from the use of tools and equipment such as scalpels and needles which resulting in cuts or punctures. Electrical hazards encompass any potential harm in the form of shock from the use of equipment like saws or defibrillators. Chemical hazards include harm from the use of a variety of chemicals used in the autopsy process such as cyanide and formaldehyde. Radiation hazards are related to any exposure from performing x-rays. Infection hazards are due to the potential that a cadaver is infected with a communicable disease.
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.
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.