This is a working overview of Certificate of analysis, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-12-23. Anything still debated is marked as such rather than presented as settled.
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.
Reported activity for Selank centers on anxiolytic and nootropic effects. Russian clinical reports describe use in anxiety and in cognitive or attention-related complaints. Most of this evidence comes from studies conducted by the same research groups that developed the peptide. Independent replication in other countries remains limited, and no major Western regulatory agency has approved the compound for any indication. The gap between local reports and external verification is a recurring point in discussions of the peptide.
Tuftsin, the parent structure, is a naturally occurring immunomodulatory tetrapeptide released from the Fc region of immunoglobulin G by spleen enzymes. Selank extends this four-residue sequence with three additional amino acids. The stated rationale is that the added tail slows enzymatic breakdown and may influence receptor interactions. How the full heptapeptide behaves at the molecular level is not firmly established, and proposed mechanisms often involve indirect modulation of neurotransmitter or immune signaling rather than a single defined target.
| 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 |
Quantification in biological matrices relies on liquid chromatography coupled to tandem mass spectrometry with stable-isotope internal standards. Low plasma concentrations and adsorption to container surfaces both complicate measurement. Solid-phase extraction is often needed to reduce matrix interference before injection. Reported limits of quantification differ widely between laboratories, which makes direct comparison of pharmacokinetic results difficult and limits meta-analysis.
Peptide bonds are vulnerable to protease attack, and Selank is no exception. Measured half-life in serum is short, on the order of minutes in several reports, which explains why intranasal administration is the common route described in the literature. Absorption across the nasal mucosa partially bypasses first-pass hepatic metabolism. Quantitative data on human bioavailability remain limited and are difficult to compare across studies.
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.
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.
Published clinical work is concentrated in Russian-language journals and generally involves small samples without independent replication. Systematic reviews in English note the shortage of randomised, placebo-controlled trials and the difficulty of verifying methods from translated reports. Outcome measures vary between studies, which complicates pooling of results. Interest in the compound as a cognitive or anxiolytic agent therefore rests on a thinner evidence base than the volume of citations suggests. Replication in well-powered trials with preregistered endpoints would be needed before firm conclusions about efficacy can be drawn.
Proposed mechanisms centre on the GABAergic system. Animal and tissue studies report changes in GABA-A receptor expression and reduced activity of GABA transaminase, the enzyme that degrades GABA. Effects on monoamine turnover, including serotonin and dopamine pathways, are also described, and a separate line of work links the peptide to increased expression of brain-derived neurotrophic factor in hippocampal tissue. Most of these findings come from rodent models and cell preparations. How the individual observations combine into a single coherent mode of action is not settled.
Pharmacokinetic data are sparse and largely derived from animal work. After intranasal administration the peptide appears in plasma within minutes, and reported half-lives are short, on the order of minutes to tens of minutes. Degradation proceeds through ordinary proteolytic cleavage into constituent amino acids and smaller fragments. Direct evidence that intact Selank reaches brain tissue in meaningful amounts is limited, and the extent of blood-brain barrier penetration is debated. Some authors argue that fragments, not the parent peptide, carry much of the observed activity.
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.
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.
== Treatment == Avoid cold weather. Treat the underlying lymphoma. No cold drinks; all drinks should be at room temperature (or above). Requires heater to maintain temperature in cold places. Treatment with rituximab has been described. The treatment of cold agglutinin disease depends on many factors including the severity of the condition, the signs and symptoms present in each person, and the underlying cause. For example, in those affected by secondary cold agglutinin disease, it is important to diagnose and treat the underlying condition which may include certain types of cancer; bacterial, viral, or parasitic infections; and/or other autoimmune disease. People with few symptoms and/or mild anemia may not require any specific treatment. These cases are often managed by simply avoiding exposure to the cold. In severe cases of hemolysis, medical interventions may be necessary. Rituximab (an antibody that selectively reduces specific types of immune cells) is effective in about 60% of cases of severe cold agglutinin disease. Medical researchers have found the response to rituximab is seen on average within 1 to 2 months of treatment and the effect of the treatment lasts for about 1 to 2 years. Rituximab may be used after a second and even a third relapse, however the success rate is less. Combined treatment with rituximab and fludarabine has resulted in higher response rates (76% of cases) and longer periods of remissions (on average, 6.5 years).
== Background == Found in several fungal species such as Fusarium graminearum NRRL 2903 (formerly misidentified as Dactylium dendroides), and other species of Fusarium and Aspergillus genera, galactose oxidase was first isolated in 1959. This enzyme is secreted by fungi to function in extracellular space. Although the oxidation reaction of D-galactose gives galactose oxidase its name, the coupled reduction of dioxygen to hydrogen peroxide is believed to have greater physiological significance in yeasts. Hydrogen peroxide which can be produced by yeasts in this way is possibly a bacteriostatic agent.
Italian left communist Amadeo Bordiga dismissed Marxism–Leninism as political opportunism that preserved capitalism because of the claim that the exchange of commodities would occur under socialism. He believed that the use of popular front organisations by the Communist International and a political vanguard organised by organic centralism were more effective than a vanguard organised by democratic centralism. Anarcho-communist Peter Kropotkin criticised Marxism–Leninism as centralising and authoritarian. Other leftists, including Marxist–Leninists, criticise it for its repressive state actions, while recognising certain advancements, such as egalitarian achievements and modernisation under those states. While Michael Parenti disagrees with blanket condemnations of former Marxist–Leninist countries, he condemned "Stalin and his autocratic system of rule and believed there were things seriously wrong with existing Soviet society.", including "serious problems of labor productivity, industrialization, urbanization, bureaucracy, corruption, and alcoholism.
This reaction is essentially the oxidation of primary alcohol using oxygen to form the corresponding aldehyde and hydrogen peroxide. It has been shown that galactose oxidase is also able to catalyze various primary alcohols other than galactose. In fact, galactose oxidase catalyzes dihydroxyacetone three times faster than it does to galactose. The reaction is regioselective, in that it cannot oxidize secondary alcohol. This two-electron oxidation is achieved by the double-redox site: the copper(II) metal center and the free radical, each capable of accepting one electron from the substrate. This double-redox center has three accessible oxidation levels. In the catalytic cycle of galactose oxidase, the enzyme shuttles between the fully oxidized form and the fully reduced form. The semi-oxidized form is the inactive form.
Sources: en.wikipedia.org
== Biology == The 7kDa proteins are universally found in Sulfolobus, where two copies (Sul7d, Sul7e) are present as separate genes. The proteins are usually named after the species, e.g. Sso7d for the 7d of S. solfataricus and Sac7e for the 7e of S. acidocaldarius. Sul7a and Sul7b are truncated versions of 7d. "Sso7c" does not appear to be a member of this family. S. tokodaii is unusual in that the two copies only differ by one nucleotide and produce the same protein, so its version is simply called Sto7. Across Sulfolobales, Acidianus, Metallosphaera, and "Candidatus Aramenus" also encode a 7kDa DNA-binding protein, named according to the genus name or the species name in an analogous fashion. Each genome may carry anywhere from 1 to 3 versions of the protein.
=== Vitamin B12 structure === In 1948, Hodgkin first encountered vitamin B12, one of the most structurally complex vitamins known, and created new crystals. Vitamin B12 had first been discovered at Merck earlier that year. It had a structure at the time that was almost completely unknown, and when Hodgkin discovered it contained cobalt, she realized the structure actualization could be determined by X-ray crystallography analysis. The large size of the molecule, and the fact that the atoms were largely unaccounted for—aside from cobalt—posed a challenge in structure analysis that had not been previously explored. From these crystals, she deduced the presence of a ring structure because the crystals were pleochroic, a finding which she later confirmed using X-ray crystallography. The B12 study published by Hodgkin was described by Lawrence Bragg as being as significant "as breaking the sound barrier". Scientists from Merck had previously crystallised B12, but had published only refractive indices of the substance. The final structure of B12, for which Hodgkin was later awarded the Nobel Prize, was published in 1955 and 1956.
1st Airborne Battle Group (ABG), 187th Infantry (reassigned from the 24th Infantry Division on 8 February 1959)(1) 1st ABG, 325th Infantry 2nd ABG, 501st Infantry 1st ABG, 503d Infantry (reassigned from the 24th Infantry Division on 1 July 1958)(2) 2nd ABG, 503rd Infantry (reassigned to the 25th Infantry Division on 24 June 1960) 1st ABG, 504th Infantry (reassigned to the 8th Infantry Division on 11 December 1958) 2nd ABG, 504th Infantry (assigned effective 9 May 1960)(1) 1st ABG, 505th Infantry (reassigned to the 8th Infantry Division on 15 January 1959) (1) 1st ABG, 504th Infantry and 1st ABG, 505th Infantry were reassigned to the 8th Infantry Division in central West Germany to provide airborne capability in Germany; in turn, 1–187th and 1-503d were reassigned from the 24th Infantry Division in southern Germany to the 82nd Airborne Division (2) 2nd ABG, 503rd Infantry was reassigned to the 25th Infantry Division and stationed in Okinawa to provide airborne capability in the Pacific on 24 June 1960. This ABG was reassigned to the 173d Airborne Brigade on 26 March 1963.
=== Health care === The Government of India had focused primarily on increasing the hospital-based services for gas victims; thus, hospitals had been built after the disaster. When UCC wanted to sell its shares in UCIL, it was directed by the Supreme Court to finance a 500-bed hospital for the medical care of the survivors. Thus, Bhopal Memorial Hospital and Research Centre (BMHRC) was inaugurated in 1998 and was obliged to give free care for survivors for eight years. BMHRC was a 350-bedded super speciality hospital where heart surgery and hemodialysis were done. There was a dearth of gynaecology, obstetrics and paediatrics. Eight mini-units (outreach health centres) were started and free health care for gas victims was to be offered until 2006. The management had also faced problems with strikes, and the quality of the health care being disputed. Sambhavna Trust is a charitable trust, registered in 1995, that gives modern as well as ayurvedic treatments to gas victims, free of charge.
=== Single-layer drug-in-adhesive === The adhesive layer of this system also contains the drug. In this type of patch the adhesive layer not only serves to adhere the various layers together, along with the entire system to the skin, but is also responsible for the releasing of the drug. The adhesive layer is surrounded by a temporary liner and a backing. It is characterized by the inclusion of the drug directly within the skin-contacting adhesive placed onto the epidermis.
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.
Selank is a synthetic peptide made of seven amino acids. It is modeled on tuftsin, a natural tetrapeptide, with an added three-residue tail. It is not a small-molecule drug.