The short version of heptapeptide fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-04-11 and is reviewed periodically as new material appears.
Quality documentation for research-grade peptide usually includes a certificate of analysis stating purity, identity, and residual counterion content. Batch-to-batch variation in purity and salt form is a recognized issue, and comparisons across suppliers require attention to the exact counterion, for example acetate versus trifluoroacetate. Sequence verification by tandem mass spectrometry provides stronger evidence than a single mass measurement. For any study reporting biological results, the analytical method and the measured purity should be stated explicitly. Independent verification of supplier claims is considered good practice.
Semax is supplied as a lyophilized powder that appears white to off-white. It dissolves readily in water, phosphate-buffered saline, and other aqueous media, which simplifies preparation of working solutions for laboratory use. The nasal products registered in Russia are dilute aqueous solutions, typically around 0.1 percent peptide by weight. Organic solvents are rarely necessary and can complicate handling. Because the peptide is hygroscopic, weighing should be performed quickly and with minimal exposure to ambient humidity.
Solid material is normally kept at minus 20 degrees Celsius in a sealed, desiccated container. Reconstituted solutions are less stable and are usually divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are avoided because they promote aggregation and loss of activity. Light exposure is minimized by using amber glassware or foil wrapping. Published stability data for this peptide are sparse, so recommended storage conditions rest mainly on general practice for short synthetic peptides rather than on dedicated study.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
| Property | Value | Notes |
|---|---|---|
| Typical purity | ≥95% by HPLC | Research-grade material |
| Detection wavelength | 214 nm | Peptide bond absorbance |
| Reconstitution medium | Sterile water or saline | Prepare fresh or aliquot immediately |
| Storage (solution) | -80 °C, single-use aliquots | Avoid repeated freeze-thaw cycles |
| Common salt form | Acetate or trifluoroacetate | Affects mass and solubility |
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
Stability depends heavily on physical state. Lyophilized powder held dry, cold and dark retains its content over long periods, whereas dissolved peptide begins to change within days at room temperature. The most cited degradation route is oxidation of the methionine residue, which converts the peptide to a sulfoxide form that elutes differently on chromatography. Hydrolysis of amide bonds and adsorption onto container walls contribute smaller losses. Buffers that exclude oxygen from the headspace slow the oxidation pathway, but no single condition prevents all change indefinitely.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
Dr. Kang found that male Gulf War veterans reported having infants with likely birth defects at twice the rate of non-veterans. Furthermore, female Gulf War veterans were almost three times more likely to report children with birth defects than their non-Gulf counterparts. The numbers changed somewhat with medical records verification. However, Dr. Kang and his colleagues concluded that the risk of birth defects in children of deployed male veterans still was about 2.2 times that of non-deployed veterans. In early 2004, the UK Pensions Appeal Tribunal Service attributed birth defect claims from a February 1991 Gulf War combat veteran to depleted uranium poisoning. Looking at the risk of children of UK Gulf War veterans suffering genetic diseases such as congenital malformations, commonly called "birth defects", one study found that the overall risk of any malformation was 50% higher in Gulf War veterans as compared to other veterans.
=== Chronic kidney disease === Although Jardiance was originally developed for treatment of type 2 diabetes, large-scale clinical trials have proven that it provides significant renal and cardiovascular benefits for a much wider range of patients, including to those with chronic kidney disease even without type 2 diabetes.
Convergent evolution is the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. The cladistic term for the same phenomenon is homoplasy. The recurrent evolution of flight is a classic example, as flying insects, birds, pterosaurs, and bats have independently evolved the useful capacity of flight. Functionally similar features that have arisen through convergent evolution are analogous, whereas homologous structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. The opposite of convergent evolution is divergent evolution, where related species evolve different traits. Convergent evolution is similar to parallel evolution, which occurs when two independent species evolve in the same direction and thus independently acquire similar characteristics; for instance, gliding frogs have evolved in parallel from multiple types of tree frog. Many instances of convergent evolution are known in plants, including the repeated development of C4 photosynthesis, seed dispersal by fleshy fruits adapted to be eaten by animals, and carnivory.
== Further reading == Bryant, Alfred T. (1964). A History of the Zulu and Neighbouring Tribes. Cape Town: C. Struik. p. 157. Cana, Frank Richardson (1911). "Zululand" . Encyclopædia Britannica. Vol. 28 (11th ed.). pp. 1050–1055. Morris, Donald R. (1965). The Washing of the Spears: the Rise of the Zulu Nation. New York: Simon and Schuster. p. 655. Deflem, Mathieu. (1999). Warfare, Political Leadership, and State Formation: The Case of the Zulu Kingdom, 1808–1879. Ethnology 38(4):371–391. Knight, Ian. (2010). Zulu Rising: The Epic Story of Isandlwana and Rorke's Drift, London: Macmillan. ISBN 978-1-405-09185-5
==== MeSH D12.125.070 – amino acids, branched-chain ==== MeSH D12.125.070.075 – aminoisobutyric acids MeSH D12.125.070.577 – isoleucine MeSH D12.125.070.637 – leucine MeSH D12.125.070.950 – valine MeSH D12.125.070.950.100 – 2-amino-5-phosphonovalerate
Sources: en.wikipedia.org
The reliability of computer systems, that is the ratio of uptime to the sum of uptime and downtime. "Five nines" reliability in a continuously operated system means an average downtime of no more than approximately five minutes per year (there is no relationship between the number of nines and minutes per year, it is pure coincidence that "five nines" relates to five minutes per year.) (See high availability for a chart.) The purity of materials, such as gases and metals.
Creatine kinase (CK) test: measures the circulating blood levels of creatine kinase an enzyme found in the heart (CK-MB), brain (CK-BB) and skeletal muscle (CK-MM). Blood urea nitrogen (BUN) test: urea nitrogen is the byproduct of protein metabolism first formed in the liver then removed from the body by the kidneys. The BUN test is primarily used to test kidney function. A low BUN level may indicate the effects of malnutrition. BUN-to-creatinine ratio: A BUN to creatinine ratio is used to predict various conditions. A high BUN/creatinine ratio can occur in severe hydration, acute kidney failure, congestive heart failure, and intestinal bleeding. A low BUN/creatinine ratio can indicate a low protein diet, celiac disease, rhabdomyolysis, or cirrhosis of the liver. Thyroid function tests: tests used to assess thyroid functioning by checking levels of thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3).
==== Economic issues ==== In 2010, Larson introduced the Small Business Jobs Act of 2010, authorizing the creation of the Small Business Lending Fund Program administered by the Treasury Department to make capital investments in eligible institutions, in order to increase the availability of credit for small businesses. Larson was a strong advocate for the American Recovery and Reinvestment Act of 2009, which increased federal spending in infrastructure, education, health and energy while expanding some welfare and social security programs. His liberal stance on government spending has earned him a rating of 9% with Citizens Against Government Waste, a conservative anti-government spending interest group.
== Clinical relevance == This reaction is important for the treatment of exposure to cyanide, since the thiocyanate formed is around 1 / 200 as toxic.:p. 15938 The use of thiosulfate solution as an antidote for cyanide poisoning is based on the activation of this enzymatic cycle.
Because of its behavior as a prodrug and its pharmacokinetic differences, lisdexamfetamine has a longer duration of therapeutic effect than immediate-release dextroamphetamine and shows reduced misuse potential. CYP2D6, dopamine β-hydroxylase (DBH), flavin-containing monooxygenase 3 (FMO3), butyrate-CoA ligase (XM-ligase), and glycine N-acyltransferase (GLYAT) are the enzymes known to metabolize amphetamine or its metabolites in humans. Amphetamine has a variety of excreted metabolic products, including 4-hydroxyamphetamine, 4-hydroxynorephedrine, 4-hydroxyphenylacetone, N-hydroxyamphetamine, benzoic acid, hippuric acid, norephedrine, and phenylacetone. Among these metabolites, the active sympathomimetics are 4-hydroxyamphetamine, 4-hydroxynorephedrine, norephedrine, and N-hydroxyamphetamine. The main metabolic pathways involve aromatic para-hydroxylation, aliphatic alpha- and beta-hydroxylation, N-oxidation, N-dealkylation, and deamination. The known metabolic pathways, detectable metabolites, and metabolizing enzymes in humans include the following:
Sources: en.wikipedia.org
=== Coiled coil proteins === Coiled coil proteins form long, insoluble fibers involved in the extracellular matrix. There are many scleroprotein superfamilies including keratin, collagen, elastin, and fibroin. The roles of such proteins include protection and support, forming connective tissue, tendons, bone matrices, and muscle fiber.
A particularly novel, high-yielding synthesis of etonitazene was developed by FI Carroll and MC Coleman in the mid-1970s The authors were tasked with the preparation of large quantities of etonitazene, but found the conventional synthesis to be inadequate. The problem with the conventional synthesis was the lability of the imino ether reactant, 2-(4-ethoxyphenyl)-acetimidic acid ethyl ester (prepared by reacting 4-ethoxyphenylacetonitrile with ethanolic HCl). The imino ether necessitated the use of anhydrous reaction conditions and was inconvenient to prepare in large quantities. This led the authors to experiment with the use of a coupling reagent, EEDQ (N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline), in order to promote the condensation of 2-(2-diethylaminoethylamino)-5-nitroaniline with 4-ethoxyphenylacetic acid. The authors discovered that when this condensation was performed in the presence of 2 or more molar equivalents of EEDQ (added portionwise in 3 steps) in THF at 50 °C for 192 hours (8 days), a near quantitative yield (100%) of etonitazene was obtained. In addition to the impressive improvement in yield over the conventional procedure, the work up procedure was greatly simplified since quinoline, carbon dioxide, and ethanol were the only by-products formed. A diagram of this procedure is shown below.
In October 2003, the People's Republic of China commenced its first crewed spaceflight, Shenzhou 5. The astronaut, Yang Liwei, brought along with him and ate specially processed yuxiang pork (Chinese: 鱼香肉丝), Kung Pao chicken (Chinese: 宫保鸡丁), and Eight Treasures rice (Chinese: 八宝饭), along with Chinese herbal tea. Food made for this flight and the subsequent crewed flight in 2007 has been commercialized for sale to the mass market. At Tiangong space station, meals consisting of 120 different types of food, selected based on astronauts' preferences, are stored aboard. Staples including shredded pork in garlic sauce, kung pao chicken, black pepper beef, yuxiang shredded pork, pickled cabbage, and beverages, including a variety of teas and juices, are resupplied by trips of the Tianzhou-class robotic cargo spacecraft. Fresh fruits and vegetables are stored in coolers. Huang Weifen, the chief astronaut trainer of CMSA, explains that most of the food is prepared to be solid, boneless, and in small pieces. Condiments such as pork sauce and Sichuan pepper sauce are used to compensate for the changes in the sense of taste in microgravity. Food items are often adjusted according to astronauts' feedback, such as when larger supplies of vegetables were included in Tianzhou 4. Additionally, China's Tiangong-2 station has conducted experiments growing food on board in a micro-gravity environment, such as thale cress, a form of edible weed, as well as rice.
The first patch for the Xbox 360 version was released about two weeks after release to fix some of the game stability issues players had reported. The patch was found to introduce more problems to the game for some users, including occasional freezes, bad framerates, and audio-related issues, though methods to resolve these issues through the console's cache system were outlined by Irrational Games. In December 2007, a common patch was released for both the Xbox 360 and Windows version. The patch included additional content such as new Plasmids, new achievements for the Xbox 360 version, and a FOV lock that allowed widescreen players a wider field of view without losing vertical information. The patch also added in an option to disable the use of Vita-Chambers, a feature requested by players to make the game more challenging, as well as an achievement to complete the game at its hardest setting without using a Vita-Chamber. In 2014, 2K Games released a DRM-free version of BioShock in the Humble 2K Bundle, followed by DRM-free releases on GOG in 2018.
Sources: en.wikipedia.org
Solid peptide is best kept frozen at about minus 20 degrees Celsius in a sealed container with desiccant. It should be allowed to reach room temperature before opening to prevent condensation. Repeated warming and cooling of the same vial is discouraged.
Reversed-phase liquid chromatography establishes purity, while mass spectrometry confirms molecular mass. The two techniques are normally used together. Retention time alone is not sufficient evidence of identity.
Different counterions change the mass per unit of peptide and can shift chromatographic behavior. Two samples of equal stated purity may therefore not be directly comparable. Reports should specify the counterion whenever quantitative comparisons are made.
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.