Everything below concerns Methionine oxidation. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-08-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Published research on this peptide originates mainly from Russian laboratories, and the wider international literature is comparatively thin. Studies have used rodent models of stroke, hypoxia, and memory tasks, with a smaller number of human trials reported. Reported outcomes include changes in attention and memory measures, along with effects on neurotrophic factor expression in some experiments. Small sample sizes, inconsistent dosing protocols, and limited independent replication are widely noted limitations, so the strength of the clinical evidence remains an open question.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
稳定性主要由水解与氧化两条路径支配。肽键在中性或弱酸性条件下相对稳定，遇到强碱或长时间高温则明显断裂；甲硫氨酸侧链容易被氧化成亚砜，使主峰前移并拉低实际含量。金属离子、光照和反复冻融会进一步促进降解或聚集。冻干粉在低温避光条件下可存放较长时间，配制后的水溶液通常需要冷藏并尽快用完。
=== Development === In November 1990, Warner Bros. Pictures purchased the film rights to "The Rest of Daniel" for $2 million, the most ever paid for a screenplay. Originally intended as a star vehicle for Gibson, he declined the opportunity to direct the feature. The film formed part of a multi-million-dollar three-year distribution deal he signed with Warner Bros., which also guaranteed him a minimum of three months off a year to spend with his family.
Chronic overdose masked by Somogyi: A dose that is too high may cause a Somogyi rebound, which can look like a need for more insulin. This condition can continue for days or weeks. High-carbohydrate cat food: Many commercial foods (especially "light" foods) are very high in carbohydrates. The extra carbohydrates keep the cat's blood sugar high. In general, canned foods are lower in carbohydrates than dry foods, and canned "kitten" foods lower still. Diabetes in cats can be better regulated and even sometimes reversed with a low-carbohydrate diet. Inappropriate insulin: Different brands and types of insulin have idiosyncratic effects on different cats. With some dosages, the insulin may not last long enough for the cat. Testing blood sugar more frequently can determine if the insulin is controlling the blood sugar concentration throughout the day.
In 1943, the Nobel committee received a single nomination for the Nobel Prize in Physiology or Medicine for Fleming and Florey from the British biochemist Rudolph Peters. The secretary of the Nobel committee, Göran Liljestrand, made an assessment of Fleming and Florey in the same year, but little was known about penicillin in Sweden at the time, and he concluded that more information was required. The following year, there was one nomination for Fleming alone and one for Fleming, Florey and Chain. Liljestrand and Nanna Svartz, the professor of medicine at the Karolinska Institute, considered their work, and while both judged Fleming and Florey equally worthy of a Nobel Prize, the Nobel committee was divided, and decided to award the prize that year instead to Joseph Erlanger and Herbert S. Gasser "for their discoveries relating to the highly differentiated functions of single nerve fibres". There were a large number of nominations for Florey and Fleming or both in 1945, and one for Chain, from Liljestrand, who nominated all three. Liljestrand noted that thirteen of the first sixteen nominations that came in mentioned Fleming, but only three mentioned him alone. This time evaluations were made by Liljestrand, Sven Hellerström and Anders Kristenson, who endorsed all three. There were rumours that the committee would award the prize to Fleming alone, or half to Fleming and one-quarter each to Florey and Chain. Fulton and Dale lobbied for the award to be given to Florey.
== Business == The company manufactures a variety of GPS (Global Positioning System) trackers intended for use in vehicles and other mobile assets. It also offers an Internet-based subscription service that gives clients access to 5- or 10-second updates around the clock from each installed GPS tracker. The system collects and stores data from each unit on a 24/7 basis, and can generate reports showing the activity of each vehicle during a specified time frame. The system can be configured to transmit alerts to the account owner if certain user-defined conditions are detected, such as a monitored vehicle exceeding acceptable speeds or entering/exiting a specific area.
=== Stress/ Hypothalamic-pituitary-adrenal (HPA) axis === GHSR1A, Ghrelin's endogenous receptor, is expressed within the hypothalamus including the arcuate nucleus, but not in the paraventricular nucleus (PVN) where ghrelin has been found to indirectly affect HPA axis function via neighboring corticotropin releasing hormone (CRH) neurons. Studies regarding how ghrelin affects cortisol and adrenocorticotropic hormone (ACTH) secretion along with how cortisol and ACTH levels affect ghrelin are inconsistent as different psychological and physical stressors within in-vivo studies have produced a myriad of results as the underlying mechanisms are still not understood well.
Sources: en.wikipedia.org
Pharmacy automation involves the mechanical processes of handling and distributing medications. Any pharmacy task may be involved, including counting small objects (e.g., tablets, capsules); measuring and mixing powders and liquids for compounding; tracking and updating customer information in databases (e.g., personally identifiable information (PII), medical history, drug interaction risk detection); and inventory management.
A series of four lectures, given by Thomson on a visit to Princeton University in 1896, were subsequently published as Discharge of electricity through gases (1897). He also presented a series of six lectures at Yale University in 1904.
2GO Group, Inc. (branded as 2GO) is a Philippine logistics and transportation company engaged in freight shipping, courier and parcel delivery, warehousing, inventory management, distribution, and passenger sea travel. It operates a fleet of ten inter-island vessels transporting cargo and passengers across domestic routes in the Philippines. The company traces its roots to William Lines, Inc., which was established on May 26, 1949. William Lines grew to become one of the largest shipping companies in the Philippines during the 1970s to the 1990s, before eventually merging with other domestic shipping firms that later formed what is now known as 2GO Group, Inc. 2GO is a subsidiary of SM Investments Corporation (SMIC), one of the country's largest conglomerates. Another principal shareholder is Trident Investments.
August 15, 2009: Portugal Portugal leaves recession after three consecutive quarters of negative growth having its GDP recover by 0.3% in the second quarter of 2009. According to the latest estimates by the Bank of Portugal, Portuguese GDP should fall around 3.5% in 2009, which is the worst figure for the country since 1975.
==== Rotary jet spinning ==== Rotary jet spinning is a technique used in the production of biotextiles, which involves the extrusion of polymer solutions or melts through a rapidly rotating spinneret. As the polymer solution or melt exits the spinneret, it is subjected to centrifugal forces, forming fine fibers. These fibers are collected to create a nonwoven fabric or scaffold structure suitable for various biomedical applications. Rotary jet spinning offers advantages such as producing highly porous structures with controllable fiber diameter and alignment, making it promising for tissue engineering and drug delivery applications in biomedicine.
Sources: en.wikipedia.org
Military logistics is the science of planning and carrying out the movement and maintenance of armed forces. In its most comprehensive sense, those aspects of military operations that deal with: a. design and development, acquisition, storage, movement, distribution, maintenance, evacuation, and disposition of materiel; b. movement, evacuation, and hospitalization of personnel; c. acquisition or construction, maintenance, operation and disposition of facilities; and d. acquisition or furnishing of services. The main difference between the concept of logistic management and supply-chain management is the level of information gathered, processes, analysed and used for decision making. An SCM-based organization not only having concerns with its immediate clients but also handles and forecasts the factors affecting directly or indirectly their supplier or suppliers or on their client or clients. If we exclude this information part out of supply chain model then we can see the logistic management part of the business.
=== Iron === Vegetarian diets typically contain amounts of iron similar to or higher than non-vegetarian diets, but the iron they provide is entirely non-heme, which is absorbed less efficiently than the heme iron found in meat, poultry, and seafood. For this reason, the Food and Nutrition Board of the National Academies sets the iron requirement for people following vegetarian diets at 1.8 times the Recommended Dietary Allowance for those who eat animal products. In estimating these values, mixed Western diets containing meat and ascorbic acid were judged to be about 15% bioavailable, while diets based mainly on cereals and vegetables were judged to be 10% bioavailable and very restricted vegetarian diets 5% bioavailable. Absorption of non-heme iron is strongly affected by other components of the same meal. Vitamin C and other organic acids increase absorption, so pairing iron-rich plant foods with citrus fruit, tomatoes, peppers, or broccoli improves uptake, while phytic acid in whole grains, legumes, nuts, and seeds, along with polyphenols in tea and coffee and high doses of calcium, inhibit it. Soaking, sprouting, and fermenting legumes and grains reduce their phytate content and improve iron availability. Plant foods that contribute meaningfully to iron intake include lentils, white beans, kidney beans, chickpeas, soybeans and tofu, spinach, cashews, pumpkin seeds, raisins, dark chocolate, and fortified breakfast cereals and breads, the last of which are among the largest sources of iron in fortified food supplies.
== Concentration and state in cells == In rat liver, the total amount of NAD+ and NADH is approximately 1 μmole per gram of wet weight, about 10 times the concentration of NADP+ and NADPH in the same cells. The actual concentration of NAD+ in cell cytosol is harder to measure, with recent estimates in animal cells ranging around 0.3 mM, and approximately 1.0 to 2.0 mM in yeast. However, more than 80% of NADH fluorescence in mitochondria is from bound form, so the concentration in solution is much lower. NAD+ concentrations are highest in the mitochondria, constituting 40% to 70% of the total cellular NAD+. NAD+ in the cytosol is carried into the mitochondrion by a specific membrane transport protein, since the coenzyme cannot diffuse across membranes. The intracellular half-life of NAD+ was claimed to be between 1–2 hours by one review, whereas another review gave varying estimates based on compartment: intracellular 1–4 hours, cytoplasmic 2 hours, and mitochondrial 4–6 hours. The balance between the oxidized and reduced forms of nicotinamide adenine dinucleotide is called the NAD+/NADH ratio. This ratio is an important component of what is called the redox state of a cell, a measurement that reflects both the metabolic activities and the health of cells. The effects of the NAD+/NADH ratio are complex, controlling the activity of several key enzymes, including glyceraldehyde 3-phosphate dehydrogenase and pyruvate dehydrogenase.
== Disadvantages == A disadvantage to MIKES is that observations are made later in the ion flight path when compared to other methods. Also, a smaller number of ions will typically decompose. This will in turn cause the sensitivity to be lower than other kinetic energy spectroscopy methods.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.