A practical reference on Certificate of analysis: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-12-19 and is reviewed periodically as new material appears.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Stabilized analog of tuftsin |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro | Single-letter form: TKPRPGP |
| Molecular formula | C33H57N11O9 | Monoisotopic mass about 751.9 Da |
| Appearance | White to off-white powder | Typically supplied as lyophilized solid |
| Solubility | Freely soluble in water | Also soluble in common polar solvents |
Outside its country of origin the compound is generally handled as a research chemical rather than an approved medicine. No regulatory approval from the United States Food and Drug Administration or the European Medicines Agency has been granted for human use. Identity and purity are normally checked by reverse-phase high-performance liquid chromatography, with mass spectrometry used to confirm the molecular mass. Lyophilised material is stored cold and desiccated, and repeated freeze-thaw cycles are avoided.
Published work on this peptide almost always uses intranasal delivery, with drops or a spray applied to the nasal mucosa. Some animal experiments have used subcutaneous or intraperitoneal injection, and a smaller number have compared routes directly. Oral administration is not a focus of the literature, because short peptides of this size are broken down by digestive enzymes and cross intestinal barriers poorly. How much of an intranasal dose reaches the bloodstream intact in humans remains an open question.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
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.
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.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
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.
The Honeywell 316 was a popular 16-bit minicomputer built by Honeywell starting in 1969. It is part of the Series 16, which includes the Models 116 (1965, discrete), 316 (1969), 416 (1966), 516 (1966) and DDP-716 (1969). They were commonly used for data acquisition and control, remote message concentration, clinical laboratory systems, Remote Job Entry and time-sharing. The Series-16 computers are all based on the DDP-116 designed by Gardner Hendrie at Computer Control Company, Inc. (3C) in 1964. The 516 and later the 316 were used as Interface Message Processors (IMP) for the American ARPANET and the British NPL Network.
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The two substrates of this enzyme are L-idonic acid and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are 5-oxo-D-gluconic acid, reduced NADH, and a proton. The enzyme can also use the alternative cofactor, nicotinamide adenine dinucleotide phosphate. 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 L-idonate:NAD(P)+ oxidoreductase.
Beyond p53, in cancer, many oncogenes and tumor suppressors have been discovered to be SUMOylated in order for the cancer to progress or not, with each SUMOylation event having one of a variety of effects. When IκB is SUMOylated, the SUMO post-translational modification outcompetes ubiquitination, protecting it from degradation, and by extension, the transcription factor NF-κB is bound in a complex with IκB, preventing the expression of genes that may otherwise cause cells with DNA damage to apoptose. In hypoxic conditions as arise in some cancers, HIF-1α, which is usually SUMOylated followed by subsequent ubiquitination and degradation through the von Hippel-Lindau tumor suppressor's ubiquitin ligase activity, is instead deSUMOylated thereby promoting survival of the tumorigenic cells. The fallout from deSUMOylation of HIF-1α includes promotion of MMPs which are understood to contribute to the progression of EMT, a hallmark of cancer. In atherosclerosis, both p53 and ERK5 are SUMOylated by the stimulus of disturbed blood flow. The stimulus is transduced by the activation of a serine/threonine kinsase called p90RSK, which phosphorylates the human SUMO protease SENP2 at the throenine amino acid residue 368. That phosphorylation is sufficient for the delocalization of the SENP2 from the nucleus. The effects of this phosphorylation-dependent SENP2 inhibition by nuclear export include the SUMOylation of p53 which leads to endothelial cell apoptosis, and SUMOylation of ERK5 which leads to inflammation.
Sources: en.wikipedia.org
== Development == The isopeptag was developed by dissecting the pilin protein (Spy0128) from Streptococcus pyogenes. Spy0128 contains two intramolecular isopeptide bonds, and to generate the isopeptag one of these bonds was split by removing the last β-strand in the protein.
=== Bismarck brown === Bismarck brown (also Bismarck brown Y or Manchester brown) imparts a yellow colour to acid mucins and an intense brown color to mast cells. One default of this stain is that it blots out any other structure surrounding it and makes the quality of the contrast low. It has to be paired with other stains in order to be useful. Some complementing stains used alongside Bismark brown are Hematoxylin and Toluidine blue which provide better contrast within the histology sample.
Mohammad-Nabi Sarbolouki (Persian: محمدنبی سربلوکی) was a distinguished Iranian biophysicist and polymer chemist and one of the most influential individuals behind modern scientific movement in Iran. He was known as the inventor of a DNA vehicle called "dendrosome". Sarbolouki was one of the main founders and pioneers of nano science, biomaterials, biotechnology and biophysics in Iran. Sarbolouki studied chemistry at Tehran University and did his PhD in Macromolecular Physical Chemistry at Polytechnic University of New York. He then spent two years at Michigan State University as a postdoctoral fellow. Sarbolouki then joined NASA where he worked as a group leader till 1981. Sarbolouki had numerous publications and patents on various subjects ranging from engineering to basic sciences. He initiated biomaterial research in Iran and was among the first to do structural biology in the country. He made significant contribution to the field of lipid bilayer membranes and liposomes, biodegradable polymers, tissue engineering, nanospheres (magnetic/fluorescent) and drug delivery. Sarbolouki was of the founding members of Iranian Society of Nanotechnology, Iranian Society of Proteomics and Iranian Chemical Society. He founded the first Biomaterial Research Center in Iran as well as National Research Center for Genetic Engineering and Biotechnology, ICGEB headquarter in Iran. Sarbolouki was involved in science policy making at the national level and was instrumental in the advancement of interdisciplinary and applied research in Iran.
Charles Miller Metzner (1931), judge on the United States District Court for the Southern District of New York and the Temporary Emergency Court of Appeals Lawrence E. Walsh (1932), independent counsel in the Iran-Contra affair; 4th United States Deputy Attorney General William Golub (1934), lawyer and advisor to Governor Nelson Rockefeller Harold Leventhal (1934), judge on the United States Court of Appeals for the District of Columbia Circuit John Slate (1935), lawyer and name partner of Skadden Arps Slate Meagher & Flom Daniel Mortimer Friedman (1937), judge of the United States Court of Appeals for the Federal Circuit, last chief judge of the United States Court of Claims, and acting solicitor general of the United States Wilfred Feinberg (1940), judge of the United States Court of Appeals for the Second Circuit Hugh H. Bownes (1941), judge of the United States Court of Appeals for the First Circuit Richard Kuh (1941), New York County district attorney and prosecutor of Lenny Bruce for obscenity Leonard I. Garth (1942), senior judge on the United States Court of Appeals for the Third Circuit Charles L. Brieant (1944), judge of the United States District Court for the Southern District of New York Jack Greenberg (1945), civil rights lawyer who argued the Brown v. Board of Education case before the United States Supreme Court Roy Cohn (1946), attorney and counsel to Sen. Joseph McCarthy Arthur Lazarus Jr. (1947), American Indian rights lawyer, argued United States v.
=== Lives Saved === A peer-reviewed research study published June, 2022 in the journal Nature Communications showed the effectiveness of fast/frequent testing using the novel low-cost and scalable saliva-based RT-qPCR assay for SARS-CoV-2 that bypasses RNA extraction called covidSHIELD reduced mortality in the community more than 4-fold relative to expected.
Sources: en.wikipedia.org
=== Admissions === The UA is considered a "selective" university by U.S. News & World Report. In the 2014–2015 academic year, 68 freshman students were National Merit Scholars. UA students hail from all states in the U.S. While nearly 69% of students are from Arizona, nearly 11% are from California, and 8% are international.
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=== Cell-free systems === Cell-free production of proteins is performed in vitro using purified RNA polymerase, ribosomes, tRNA and ribonucleotides. These reagents may be produced by extraction from cells or from a cell-based expression system. Due to the low expression levels and high cost of cell-free systems, cell-based systems are more widely used.
The Phosphagen System (ATP-PCr) occurs in the cytosol (a gel-like substance) of the sarcoplasm of skeletal muscle, and in the myocyte's cytosolic compartment of the cytoplasm of cardiac and smooth muscle.
Sources: en.wikipedia.org
Selank is a synthetic heptapeptide designed as a stabilized analog of the natural tetrapeptide tuftsin. It has been investigated mainly for anxiolytic and cognitive effects. It is not an approved pharmaceutical in most countries.
It was developed in Russia, at the Institute of Molecular Genetics of the Russian Academy of Sciences, during the 1990s. Most published research originates from Russian institutions. Independent international replication remains limited.
Tuftsin is a natural tetrapeptide with the sequence Thr-Lys-Pro-Arg that participates in immune signaling. Selank extends that sequence with Pro-Gly-Pro at the C-terminus. The added residues are linked to greater resistance to enzymatic breakdown.
Dry powder is normally held at -20 degrees Celsius or below in a sealed, light-protected container with desiccant. Brief room-temperature handling during weighing is generally tolerated. Storage instructions vary between suppliers, so the accompanying certificate of analysis should be followed.