This is a working overview of proteolysis, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-10 and is reviewed periodically as new material appears.
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.
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.
Selank is a synthetic heptapeptide developed in Russia. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro, a seven-residue chain built around the natural tetrapeptide tuftsin. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences first described the compound in the mid-1990s. The design combined the tuftsin core with an added Pro-Gly-Pro tail, a modification intended to extend the molecule's stability in biological fluids. Published work on the peptide has appeared mainly in Russian-language journals.
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.
| 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 |
Reverse-phase high-performance liquid chromatography with ultraviolet detection near 214 nanometres is the standard purity method. Mass spectrometry, typically electrospray ionisation, confirms identity through the expected mass-to-charge pattern. Amino acid analysis can verify composition independently. Chiral purity requires separate techniques such as derivatisation followed by chromatographic separation, and such data are rarely reported for research-grade material.
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.
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.
=== Anticancer therapeutics === Intracellular heat shock proteins are highly expressed in cancerous cells and are essential to the survival of these cell types due to presence of mutated and over-expressed oncogenes. Many HSPs can also promote invasiveness and metastasis formation in tumours, block apoptosis, or promote resistance to anti-cancer drugs. Hence small molecule inhibitors of HSPs, especially Hsp90 show promise as anticancer agents. The potent Hsp90 inhibitor 17-AAG was in clinical trials for the treatment of several types of cancer, but for various reasons unrelated to efficacy did not go on to Phase 3. HSPgp96 also shows promise as an anticancer treatment and is currently in clinical trials against non-small cell lung cancer.
=== Bacterial or viral === As bacterial and viral infections can both cause the same kinds of symptoms, it can be difficult to distinguish which is the cause of a specific infection. Distinguishing the two is important, since viral infections cannot be cured by antibiotics whereas bacterial infections can.
The Russian Foreign Ministry summoned senior US diplomats after comments on 21 May by US National Security Adviser Jake Sullivan appeared to support Ukrainian attacks on Russian-annexed Crimea using Western weaponry. The German Defence Ministry said it was moving its Patriot missile battery deployed in Slovakia to Lithuania to secure the NATO summit to be held in Vilnius in July. The Prosecutor-General of Ukraine released figures showing that at least 483 children had been killed during the conflict and nearly 1,000 others were wounded, with the National Social Service of Ukraine saying that nearly 1,500 children had been orphaned. Most of these casualties came from Donetsk Oblast, with 462 recorded individuals. 278 casualties were recorded in Kharkiv Oblast, 128 in Kyiv Oblast, 102 in Kherson Oblast, 91 in Zaporizhzhia Oblast, 89 in Mykolaiv Oblast, 72 in Dnipropetrovsk Oblast, 70 in Chernihiv Oblast and 67 in Luhansk Oblast. UNICEF also said an estimated 1.5 million Ukrainian children were at risk of depression, anxiety, post-traumatic stress disorder and other mental health issues. The intelligence directorate of the Ukrainian Defence Ministry warned of a plot by Russia to stage an incident at the Zaporizhzhia Nuclear Power Plant to stall Ukraine's anticipated counteroffensive. Canada's Defence Minister Anita Anand announced that her country would supply the Ukrainian Air Force with 43 AIM-9X Block II Sidewinder missiles to help intercept Kh-101 and Shahed type Iranian made Drones. It is the first official acknowledged delivery of western air to air missiles.
Danaparoid, a mixture of heparan sulfate, dermatan sulfate, and chondroitin sulfate can be used as an anticoagulant in patients having developed HIT. Because danaparoid does not contain heparin or heparin fragments, cross-reactivity of danaparoid with heparin-induced antibodies is reported as less than 10%. The effects of heparin are measured in the lab by the activated partial thromboplastin time (aPTT), one of the measures of the time it takes the blood plasma to clot. Partial thromboplastin time should not be confused with prothrombin time, or PT, which measures blood clotting time through a different pathway of the coagulation cascade.
== Population pharmacokinetics == Population pharmacokinetics (popPK) is the study of the sources and correlates of variability in drug concentrations among individuals who are the target patient population receiving clinically relevant doses of a drug of interest. Certain patient demographic, pathophysiological, and therapeutical features, such as body weight, excretory and metabolic functions, and the presence of other therapies, can regularly alter dose-concentration relationships and can explain variability in exposures. For example, steady-state concentrations of drugs eliminated mostly by the kidney are usually greater in patients with kidney failure than they are in patients with normal kidney function receiving the same drug dosage. Population pharmacokinetics seeks to identify the measurable pathophysiologic factors and explain sources of variability that cause changes in the dose-concentration relationship and the extent of these changes so that, if such changes are associated with clinically relevant and significant shifts in exposures that impact the therapeutic index, dosage can be appropriately modified. Additionally, an advantage of population pharmacokinetic modelling is its ability to analyze sparse data sets (sometimes only one concentration measurement per patient is available).
Sources: en.wikipedia.org
The pellagra epidemic in the American south had subsided in periods of low cotton production (late 1910s to early 1920s, the Great Depression), but it had consistently rebounded as cotton production recovered. The cause would not be understood until 1937, when the relation with niacin was discovered. Voluntary food fortification and periods of mandatory fortification on the state and federal levels soon followed, coinciding with a continuous drop in pellagra deaths. By the 1950s, the disease was virtually eliminated from the US.
The two substrates of this enzyme are L-lysine and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are (2S)-2,3,4,5-tetrahydropyridine-2-carboxylic acid (1), ammonia, reduced NADH, and a proton. The enzyme is highly specific for L-lysine as substrate, although S-(2-aminoethyl)-L-cysteine can act as a substrate, but more slowly.
== Management == As of 2019, no disease-modifying pharmaceuticals are known. Both strength and aerobic exercise have shown to be beneficial, although strenuous and excessive exercise should be avoided. Physical therapy can address contractures. Orthopedic surgery address foot deformities, scoliosis, Achilles tendon contractures, and winged scapula. Winged scapula can be addressed with either scapulopexy or scapulothoracic fusion. Circumstances to avoid include extremes of body weight, bone fractures, and prolonged immobility.
=== Borderlands and studio expansion (2009–2015) === Work on a new intellectual property, Borderlands, began around 2005 and was first announced in 2007. Pitchford likened the game as a combination of computer role-playing games such as Diablo and NetHack, and first-person shooters like Duke Nukem. Defining features of Borderlands was its outlined graphical style and its procedurally-generated loot system that was capable of generating millions of different guns and other gear items. Borderlands was released in October 2009, published by 2K, a subsidiary of Take-Two Interactive. By August 2011, had sold over 4.5 million copies, making it a critical success for Gearbox and allowing it to expand the studio and budgets for subsequent games. Subsequently, Gearbox developed two additional games in the video game series, Borderlands 2 (2012) and Borderlands 3 (2019), as well as the spin-off title Tiny Tina's Wonderlands (2022), and the series has spawn additional games from other studios under 2K/Take-Two or through license, including Borderlands: The Pre-Sequel by 2K Australia, and Tales from the Borderlands from Telltale Games. Gearbox and Take-Two have also partnered with Lionsgate to develop a live-action Borderlands film, which was released on August 9, 2024. In July 2013, Gearbox announced plans to rerelease Homeworld and Homeworld 2 in high definition for modern PC platforms, in addition to making it available through digital distributors.
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.