Everything below concerns TKPRPGP. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2025-09-25. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
Characterization of Selank in laboratory settings relies on standard peptide analytical techniques. Reverse-phase high-performance liquid chromatography separates the peptide from related impurities and degradation products, while mass spectrometry confirms molecular identity through accurate mass measurement. Amino acid analysis and peptide sequencing verify the primary structure when reference material is unavailable. Because Selank is a short chain, fragmentation-based analysis produces a diagnostic ion pattern that supports confident identification.
| Property | Value | Notes |
|---|---|---|
| Typical purity specification | 95 percent or higher by RP-HPLC | Area percentage of the main peak |
| Identity confirmation | Electrospray ionization mass spectrometry | Observed mass compared with the theoretical value near 751.9 Da |
| Recommended dry storage | -20 °C, desiccated | -80 °C for multi-year archival material |
| Solution handling | Prepare fresh; avoid long storage | Sterile filtration reduces microbial load |
| Common synonyms | TKPRPGP; TP-7 | Sequence code and laboratory designation used interchangeably |
Measuring peptide exposure inside the brain is technically difficult. Selank is degraded rapidly in plasma, and assays must separate intact peptide from fragments, which favors targeted mass spectrometry over immunoassays alone. Reported half-lives are short, on the order of minutes, so effects observed hours later are attributed to downstream signaling rather than to the parent compound. Blood-brain barrier permeability is debated and rarely quantified directly. Gaps include absent dose-response characterization, inconsistent reporting of purity, and almost no pharmacokinetic data from human participants.
Selank is studied chiefly as an animal-model anxiolytic with proposed secondary effects on memory and immune signaling. Reported mechanisms include modulation of the GABA-A receptor complex, inhibition of enkephalin-degrading enzymes, and shifts in monoamine turnover within limbic structures. Some experiments describe increased expression of brain-derived neurotrophic factor in the hippocampus after repeated dosing. No single molecular target has been confirmed, and the peptide does not bind any receptor with the selectivity typical of a conventional small-molecule drug. Mechanism therefore remains a set of hypotheses rather than an established pathway.
Laboratory work relies on standard behavioral paradigms. Rodents are tested in the elevated plus maze, open field, and passive avoidance tasks, with outcomes compared against diazepam or vehicle controls. Intranasal dosing is used most often because it bypasses first-pass metabolism, though intraperitoneal and intravenous routes also appear in published protocols. Biochemical endpoints include tissue BDNF concentrations, cytokine levels, and monoamine metabolites. Human data are limited to small Russian trials reporting reduced anxiety scores; most were not prospectively registered, and few employed independent outcome assessment.
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.
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.
=== Other uses === As a generic software platform, DHIS2 has been adapted for a variety of use cases both within and beyond the health sector. In addition to the most common uses listed above, examples of known DHIS2 projects include water and sanitation, nutrition and food security, agriculture and land management, and e-governance.
It was replaced in 1996 with a tan outer bag that was better suited for service in the deserts of the Middle East. By 2000, a bean burrito main dish was introduced. In 2006, "Beverage Bags" were introduced to the MRE, as service members have begun to depend more on hydration packs than on canteens, thus denying them the use of the metal canteen cups (shaped to fit in a canteen pouch with the canteen) for mixing powdered beverages. In addition to having measuring marks to indicate levels of liquid for precise measurement, they can be sealed and placed inside the flameless heater. Most recently, MREs have been developed using the Dietary Reference Intake, created by the Institute of Medicine (IOM). The IOM indicated service members (who were classified as highly active men between the ages of 18 and 30) typically burn about 4,200 Calories (kcal) a day, but tended to only consume about 2,400 Calories a day during combat, entering a negative energy balance. This imbalance occurs when service members fail to consume full portions of their rations. Although manipulations to the food items and distribution of macronutrients to help boost the amount of kilocalories per MRE have been made, more studies are showing many service members still do not meet today's standards of daily consumption, often trading and discarding portions of the ration. Researchers continue to study the habits and eating preferences of service members, making constant changes that encourage service members to eat the entire meal and thus get full nutritional value.
Many units of insulin can be wasted while refilling the pump's reservoir, filling the tubing, or changing an infusion site. This may affect prescription and dosage information. In February 2025 the FDA alerted patients of a safety concern of insulin that rely on a smartphone to deliver critical safety alerts, because reports showed that people were missing alerts due to technology configuration issues. When flying in airplanes the cabin pressure changes can cause under- or over-delivery of insulin in certain pumps, putting insulin pump users at risk of unexpected hypoglycemia or hyperglycemia.
After having tried for a long time to make bread with potatoes, Antoine Parmentier understood that this tuber should be considered as a versatile vegetable, and that its use required the popularization of recipes that would make it a main food. In his Examen chymique des pommes de terre published in 1773, he cites (but without giving the precise date) the composition of a menu that he had served to friends:
As an actor, Ice-T played small parts in the films Breakin' (1984) and its sequels, Breakin' 2: Electric Boogaloo and Rappin' (1984 and 1985 respectively), before his major role debut, starring as police detective Scotty Appleton in New Jack City (1991). He received top billing for his role in Surviving the Game (1994) and continued to appear in small roles in TV series and other films throughout the 1990s. Since 2000, he has portrayed NYPD detective/sergeant Odafin Tutuola on the NBC police drama Law & Order: Special Victims Unit, making him the longest-running male series actor in American TV history, according to Deadline. A reality television show titled Ice Loves Coco ran for three seasons (2011–2013) on E!, featuring the home life of Ice-T and his wife Coco Austin. In 2018, he began hosting the true crime documentary In Ice Cold Blood on the Oxygen cable channel, which ran for three seasons.
Sources: en.wikipedia.org
Homeobox protein cut-like 1 is a protein that in humans is encoded by the CUX1 gene (previously CUTL1). This protein is a homeodomain protein. The term "cut" in the name "cut-like 1" derives from the "cut wing" phenotype observed in a mutant of Drosophila melanogaster. In mammals, a CCAAT-displacement activity was originally described in DNA binding assays. The human gene was identified following purification of the CCAAT-displacement protein (CDP) and has been successively been called CDP, Cut-like 1 (CUTL1), CDP/Cut and finally, CUX1. (Consequently, a literature search for CUX1 fails to bring up many of the earlier studies). Cut homeobox genes are present in all metazoans. In mammals, CUX1 is expressed ubiquitously in all tissues. A second gene, called CUX2, is expressed primarily in neuronal cells.
covalent bond Also molecular bond. A bond that involves the sharing of electron pairs between atoms. The stable balance of attractive and repulsive forces that occurs between atoms when they share electrons is known as covalent bonding.
23 January – The largest interstellar organosulfur molecule (2,5-cyclohexadiene-1-thione) so far is identified in a molecular cloud about 27,000 light-years from Earth near the Galactic Center. 24 January – AES Andes abandons the INNA project to produce hydrogen and ammonia in Chile criticised for its potentially negative impact on astronomical observations at Paranal Observatory and Extremely Large Telescope. 27 January – HD 137010 b, a cool Earth-sized transiting exoplanet candidate 146 light years away, orbiting near the outer edge of its star's habitable zone, is discovered in Kepler K2 data from 2017. 28 January – Researchers at Google DeepMind publish a study on AlphaGenome, a deep learning model that predicts the functional effects of genetic variants across multiple regulatory modalities from long DNA sequences, improving interpretation of non-coding regions of the genome.
In the 1960s, the BOR Code of Ethics and Standards of Conduct placed professional limitations on medical technologists requiring "A medical technologist will work at all times under the direction or supervision of a pathologist or other duly qualified and licensed doctor of medicine, such qualifications being determined on the basis of accepted medical ethics" and that "A medical technologist will not act as owner, co-owner, advisor or employee, or by means of any subterfuge, participate in an arrangement whereby an individual not regularly licensed to practice medicine is enabled to own or operate a laboratory of clinical pathology." In 1965, Janet Higgins, an ASCP certified medical technologist, was removed from the Board of Registry (BOR) because she was employed at a New Jersey laboratory where the director was a state-licensed bio-analytical laboratory director, but not a physician. Though New Jersey has never required the certification for employment, the technologist successfully sued ASCP under monopolistic restraint of trade to be reinstated to the registry with the Supreme Court of New Jersey finding that the "professional status conferred on plaintiff by her certificate is an interest of sufficient substance to warrant the protection of the court." The lawsuit, and the focus on pathologists over medical technologists spurred other medical technologist societies, such as the American Society for Medical Technology (ASMT) to promote the creation of their own certifying boards.
== Career == At the institute, later Rockefeller University, he worked as an Assistant for Dr. D.W. Woolley on a dinucleotide growth factor he discovered in graduate school and on peptide growth factors that Woolley had discovered earlier. These studies led to the need for peptide synthesis and, eventually, to the idea for solid phase peptide synthesis (SPPS) in 1959. In 1963, he was sole author of a classic paper in the Journal of the American Chemical Society in which he reported a method he called "solid phase peptide synthesis". This article is the fifth most cited paper in the journal's history. In the mid-60s Dr. Merrifield's laboratory first synthesized bradykinin, angiotensin, desamino-oxytocin and insulin. In 1969, he and his colleague Bernd Gutte announced the first synthesis of the enzyme ribonuclease A. This work proved the chemical nature of enzymes. Dr. Merrifield's method greatly stimulated progress in biochemistry, pharmacology and medicine, making possible the systematic exploration of the structural basis of the activities of enzymes, hormones and antibodies. The development and applications of the technique continued to occupy his laboratory, where he remained active at the bench until recently. In 1993, Jeffrey I. Seeman published Life during a Golden Age of Peptide Chemistry, Merrifield's autobiography, in the series "Profiles, Pathways, and Dreams" for the American Chemical Society. He received the Association of Biomolecular Resource Facilities Award for outstanding contributions to Biomolecular Technologies in 1998.
Sources: en.wikipedia.org
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.
A reported purity value reflects the share of the main peak in one chromatographic run and says nothing about identity. Confirming that the expected sequence is present requires a separate measurement such as mass spectrometry. Purity and identity are distinct questions.
A mass spectrum reports the molecular masses present in a sample and shows whether they match the value expected for selank, near 751.9 Da. It also flags common artifacts such as truncation or adduct formation. It does not establish correct stereochemistry or complete sequence order on its own.
The most common approach combines reverse-phase liquid chromatography with mass spectrometry. Chromatography separates the components while mass spectrometry confirms the molecular mass. Peptide sequencing or tandem mass analysis can further verify the amino acid order.