en · de · es · pt
selank-notes.peptides1004.com › Wiki › Selank Origin And Chemical Identity — Worked Examples

Selank Origin And Chemical Identity — Worked Examples

By Editorial Desk · published 2025-12-28 · last reviewed 2026-02-17 · Wiki

This is a working overview of tuftsin, written for readers who want more than a one-paragraph summary but less than a textbook.

This page was last updated on 2026-02-17 and is reviewed periodically as new material appears.

Selank Origin and Chemical Identity

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.

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.

Identity and Structural Background

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.

Selank at a glance

PropertyValueNotes
Chemical classSynthetic heptapeptideAnalog of the tetrapeptide tuftsin
SequenceThr-Lys-Pro-Arg-Pro-Gly-ProReported consistently across pharmacopoeial descriptions
AppearanceWhite to off-white lyophilized powderTypical form of research-grade material
SolubilityFreely soluble in waterAqueous buffers; poor in nonpolar solvents
Typical storage temperature-20 degrees CelsiusLyophilized powder; protect from moisture

Storage, Analysis, and Regulatory Status

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.

Related pages on this site

Analytical Methods And Storage Stability

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.

Analytical Methods and Stability

Handling follows standard practice for research peptides. Material is weighed in a low-humidity environment because the powder absorbs atmospheric moisture. Purity is reported as the percentage area of the main peak in a chromatogram, with specifications commonly set at 95 percent or higher; values below that threshold indicate the presence of truncated or modified species. Residual trifluoroacetate from purification is often present and may affect mass balance. Certificates of analysis should state the analytical method, the column and gradient used, and the lot-specific retention time so that results can be compared across suppliers.

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.

Origins and Proposed Mechanisms

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.

Background from the literature

Historians credited the increased marketing of skin whiteners to the culture of the Jim Crow era, as black Americans faced continued social and legal restrictions. Cosmetic advertisements directed at black consumers often framed resulting lighter complexions as cleaner and better. Simultaneously, cosmetic and beauty magazines often published criticisms of black women who used skin bleachers, arguing that they appeared unnatural and fraudulent. In the 1930s, tanned skin became popular among white women as a new symbol of wealth. Some historians assert that industrialization had created indoor settings for labor, causing tanned skin to be associated more with sunbathing, travel, and leisure. The growth of the Black is Beautiful movement in the 1960s, combined with greater awareness of potential health hazards, also temporarily slowed the sale and popularity of skin bleachers. However, by the 1980s, paler skin once again became more desirable, as tanning became linked to premature aging and sun damage.

==== Pit closures ==== Heseltine's responsibilities also included Energy, as the separate Energy ministry was abolished. Electricity companies now decided on their own contracts, rather than being obliged by the government to choose British coal. With plans being made for the privatisation of British Coal, on 13 October 1992 Heseltine and British Coal both separately announced that 31 of British Coal's 50 pits were to close, with the loss of 30,000 jobs. Most of the detailed work had been done by the minister of state Tim Eggar. Many of the mines in Nottinghamshire that had continued working during the 1984–1985 strike were to close. Although this policy was seen by the Nottinghamshire miners as a betrayal, there was hardly any organised resistance to the programme. The government stated that since the pits were losing money they could be sustained only through unjustifiable government subsidies. Mine supporters pointed to the mines' high productivity rates and to the fact that their monetary losses were due to the large subsidies that other European nations were giving to their coal industries. An early leak had seen little reaction but Heseltine was taken aback by the public anger. Over 100 pits had closed since the 1984–1985 strike. The closures were to be rushed because the Treasury, under pressure from Major, had agreed to make money for generous redundancy settlements available only in the 1992–1993 fiscal year.

=== China === In 2024, China’s supreme court and chief prosecutor jointly issued the Interpretation of Several Issues Concerning the Application of Law in Handling Criminal Cases of Money Laundering (2024). In American and British English, this title would translate to Money Laundering Prosecution Guidelines, and they explain how Criminal Law act section 191 applies to money laundering proceeds from specific unlawful activities. The guidelines treat money laundering done for concealment of criminal proceeds as a section 191 criminal offense both when tied to the offender’s own unlawful activity and when tied to unlawful activity committed by others, and directs courts to assess whether a defendant met a knowledge or reason-to-know standard based on totality-of-the-circumstances factors. The guidelines also identify aggravating circumstances where at least 5,000,000 yuan is laundered with specified sentencing enhancements, sets mandatory minimum fine amounts of 10,000 yuan for sentences up to five years imprisonment or jail and 200,000 yuan for sentences of five to ten years, superseding prior guidance from 2009 money laundering adjudicative guidelines. It is regulated by the China Anti-Money Laundering Monitoring and Analysis Center

Sources: en.wikipedia.org

Reference notes

== History == BCSIR traces its roots back to the days of East Pakistan. East Regional Laboratories of Pakistan Council of Scientific and Industrial Research (PCSIR) was established in Dhaka in 1955. Subsequently, PCSIR laboratories were established in Rajshahi (1965) and in Chittagong (1967). After the independence of Bangladesh in 1971, BCSIR was established by a resolution of the Government of the People's Republic of Bangladesh which subsequently was reconstituted as the Bangladesh Council of Scientific and Industrial Research through a Presidential Ordinance namely Ordinance No. (V) of 1978.

== Checkups == Although the symptoms of diabetes mellitus such as frequent urination, thirstiness, greater appetites and inactiveness are easily visible, frequent checking of the dog for the disease is required. The dog's body weight should be determined and calculated once every two weeks using weight scale. The daily caloric requirement by the dog's body and BCS should also be determined using a scale as part of dietary management in maintaining average body weight. The protein intake by the dog should also be considered and checked twice a month. Blood pressure of the dog should also be constantly and daily checked in order to predict any future occurrence. The blood sugar level may also be checked using glucometer to check the glucose level in the body of the dog.

CIVIL RECORDS Held in the 20 arrondissement town halls: Births from 1925 to the present. Marriages from 1948 to the present. Deaths from 1987 to the present. Available at the Paris Archives: Before 1860: Births, marriages, and deaths from the 16th century to 1859—alphabetical-chronological indexes and records of the so-called “reconstructed” civil status from former parishes of Paris, the 12 former arrondissements, and fully or partially annexed communes in 1860. From 1860 onwards: Decennial tables: Births, marriages, and deaths up to 1932. Marriages from 1955 to 1974. Deaths from 1955 to 1984. Annual tables: Marriages from 1933 to 1954 (only record numbers are listed). Deaths from 1933 to 1954 (only record numbers are listed) and from 1985–1986. Records: Births up to 1922. Marriages up to 1947. Deaths up to 1986. Available on-site at the Paris Archives: Records from the second reconstruction (V.5.E). 29 registers of parish or civil status records from the 18th and 19th centuries not destroyed in 1871 (V.6.E 1–29). Births from 1923 and 1924. CATHOLIC RECORDS Baptisms, marriages, and burials from the 16th century to 1792—about 50 parish registers, mostly containing excerpts, preserved at the National Archives and the National Library. Baptisms, marriages, and burials from all Parisian churches from 1793 to 1909 (with gaps): First copies preserved in parishes (a single register for burials). Second copies (baptisms and marriages only) deposited at the Paris Archives by the Archdiocese.

Sources: en.wikipedia.org

Reference notes

=== Contaminant removal === Graphene oxide is non-toxic and biodegradable. Its surface is covered with epoxy, hydroxyl, and carboxyl groups that interact with cations and anions. It is soluble in water and forms stable colloid suspensions in other liquids because it is amphiphilic (able to mix with water or oil). Dispersed in liquids it shows excellent sorption capacities. It can remove copper, cobalt, cadmium, arsenate, and organic solvents.

== First Ministry == The Governor, Ken Michael, designated 17 principal executive offices of the Government under section 43(2) of the Constitution Acts Amendment Act 1899. The following ministers and parliamentary secretaries were then appointed to the positions, and served until the reconstitution of the Ministry on 14 December 2010. The list below is ordered by decreasing seniority within the Cabinet, as indicated by the Government Gazette and the Hansard index. Blue entries indicate members of the Liberal Party, green entries indicate members of the National Party, and grey indicates an Independent.

Relatively strong reducing acids can have antinutrient effects by binding to dietary minerals such as iron and zinc in the gastrointestinal tract and preventing them from being absorbed. Examples are oxalic acid, tannins and phytic acid, which are high in plant-based diets. Calcium and iron deficiencies are not uncommon in diets in developing countries where less meat is eaten and there is high consumption of phytic acid from beans and unleavened whole grain bread. However, germination, soaking, or microbial fermentation are all household strategies that reduce the phytate and polyphenol content of unrefined cereal. Increases in Fe, Zn and Ca absorption have been reported in adults fed dephytinized cereals compared with cereals containing their native phytate.

The molecular weight of prothrombin is approximately 72,000 Da. The catalytic domain is released from prothrombin fragment 1.2 to create the active enzyme thrombin, which has a molecular weight of 36,000 Da. Structurally, it is a member of the large PA clan of proteases. Prothrombin is composed of four domains; an N-terminal Gla domain, two kringle domains and a C-terminal trypsin-like serine protease domain. Factor Xa with factor V as a cofactor leads to cleavage of the Gla and two Kringle domains (forming together a fragment called fragment 1.2) and leave thrombin, consisting solely of the serine protease domain. As is the case for all serine proteases, prothrombin is converted to active thrombin by proteolysis of an internal peptide bond, exposing a new N-terminal Ile-NH3. The historic model of activation of serine proteases involves insertion of this newly formed N-terminus of the heavy chain into the β-barrel promoting the correct conformation of the catalytic residues. Contrary to crystal structures of active thrombin, hydrogen-deuterium exchange mass spectrometry studies indicate that this N-terminal Ile-NH3 does not become inserted into the β-barrel in the apo form of thrombin. However, binding of the active fragment of thrombomodulin appears to allosterically promote the active conformation of thrombin by inserting this N-terminal region.

Sources: en.wikipedia.org

Frequently asked questions

What is Selank?

Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.

How does it relate to tuftsin?

The first four residues of Selank reproduce the tuftsin sequence Thr-Lys-Pro-Arg. A Pro-Gly-Pro extension at the C-terminus was added to slow enzymatic breakdown and extend residence time.

Is Selank an approved medicine?

It holds marketing authorization in Russia, where nasal drop formulations are sold. No equivalent approval exists in the European Union, the United States, or most other countries.

What is the peptide sequence of Selank?

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.

Network