A practical reference on Methionine oxidation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-06-06 and is reviewed periodically as new material appears.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
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。
纯度评估以反相高效液相色谱为主，通过主峰面积百分比给出粗略结果，再配合电喷雾质谱核对分子量。氨基酸分析可验证组成比例，手性色谱或毛细管电泳用于检查残基构型。常见杂质包括缺失序列的短肽、氧化产物与二聚体。由于多数市售品不附带完整检验报告，独立第三方检测常被用来核实标称值。
== Synthesis and Post-translational Modification == Proinsulin is synthesized on membrane associated ribosomes found on the rough endoplasmic reticulum, where it is folded and its disulfide bonds are oxidized. It is then transported to the Golgi apparatus where it is packaged into secretory vesicles, and where it is processed by a series of proteases to form mature insulin. Mature insulin has 35 fewer amino acids; 4 are removed altogether, and the remaining 31 form the C-peptide. The C-peptide is abstracted from the center of the proinsulin sequence; the two other ends (the B chain and A chain) remain connected by disulfide bonds. The post translational modification of proinsulin to mature insulin only occurs in the beta cells of the pancreatic islets. When proinsulin is transported through the Golgi apparatus the C-peptide is cleaved. This cleavage occurs with the aid of two endoproteases. Type I endoproteases, PC1 and PC3, disrupt the C peptide-B chain connection. PC2, a type II endoprotease, cleaves the C peptide-A chain bond. The resulting molecule, now mature insulin, is stored as a hexamer in secretory vesicles and is stabilized with
== Types == The types of intrauterine devices available and the names they go by differ by location. The WHO ATC labels both copper and hormonal devices as IUDs. In the United Kingdom, there are more than 10 different types of copper IUDs available. In the United Kingdom, the term IUD refers only to these copper devices. Hormonal intrauterine contraception is labeled with the term intrauterine system (IUS). In the United States, there are two types available:
=== Machine learning and statistics === In machine learning, one-hot encoding is a frequently used method to deal with categorical data. Because many machine learning models need their input variables to be numeric, categorical variables need to be transformed in the pre-processing part.
== Sources == Bamforth, Charles; Food, Fermentation and Micro-organisms, Wiley-Blackwell, 2005, ISBN 0-632-05987-7 Bamforth, Charles; Beer: Tap into the Art and Science of Brewing, Oxford University Press, 2009 Boulton, Christopher; Encyclopaedia of Brewing, Wiley-Blackwell, 2013, ISBN 978-1-4051-6744-4 Briggs, Dennis E., et al.; Malting and Brewing Science, Aspen Publishers, 1982, ISBN 0-8342-1684-1 Ensminger, Audrey; Foods & Nutrition Encyclopedia, CRC Press, 1994, ISBN 0-8493-8980-1 Esslinger, Hans Michael; Handbook of Brewing: Processes, Technology, Markets, Wiley-VCH, 2009, ISBN 3-527-31674-4 Hornsey, Ian Spencer; Brewing, Royal Society of Chemistry, 1999, ISBN 0-85404-568-6 Hui, Yiu H.; Food Biotechnology, Wiley-IEEE, 1994, ISBN 0-471-18570-1 Hui, Yiu H., and Smith, J. Scott; Food Processing: Principles and Applications, Wiley-Blackwell, 2004, ISBN 978-0-8138-1942-6 Andrew G.H. Lea, John Raymond Piggott, John R.
Sources: en.wikipedia.org
Gastrin-releasing peptide GRP, is a neuropeptide, a regulatory molecule encoded in the human by the GRP gene. GRP has been implicated in a number of physiological and pathophysiological processes. Most notably, GRP stimulates the release of gastrin from the G cells of the stomach. GRP encodes a number of bombesin-like peptides. Its 148-amino acid preproprotein, following cleavage of a signal peptide, is further processed to produce either the 27-amino acid gastrin-releasing peptide or the 10-amino acid neuromedin C. These smaller peptides regulate numerous functions of the gastrointestinal and central nervous systems, including release of gastrointestinal hormones, smooth muscle cell contraction, and epithelial cell proliferation.
=== Piperidines and tropanes === Tropane alkaloids occur in plants of the families erythroxylaceae (including coca). Piperidine and its derivatives are ubiquitous building blocks in the synthesis of many pharmaceuticals and fine chemicals.
These hormones will cause the masculinization of the phenotypically indifferent organs. When exposed to testosterone, the genital tubercle elongates to form the penis. By fusion of the urogenital folds—elongated spindle-shaped structures that contribute to the formation of the urethral groove on the belly aspect of the genital tubercle—the urogenital sinus closes completely to form the spongy urethra and the labioscrotal swellings unite to form the scrotum. The secretion of testosterone during this phase plays a decisive role in the final shaping of the penis. After birth, testosterone levels drop significantly until puberty.
Another application is in the diagnosis of tularemia. An evaluation of the Western blot's ability to detect antibodies against F. tularensis revealed that it has a sensitivity of almost 100% and a specificity of 99.6%. Some forms of Lyme disease testing employ Western blotting. A Western blot can also be used as a confirmatory test for hepatitis B infection and HSV-2 (herpes type 2) infection. In veterinary medicine, a Western blot is sometimes used to confirm FIV+ status in cats. Further applications of the Western blot technique include its use by the World Anti-Doping Agency (WADA). Blood doping is the misuse of certain techniques and/or substances to increase one's red blood cell mass, which allows the body to transport more oxygen to muscles and therefore increase stamina and performance. There are three widely known substances or methods used for blood doping, namely, erythropoietin (EPO), synthetic oxygen carriers and blood transfusions. Each is prohibited under WADA's List of Prohibited Substances and Methods. The Western blot technique was used during the 2014 FIFA World Cup in the anti-doping campaign for that event. In total, over 1000 samples were collected and analysed by Reichel, et al. in the WADA-accredited Laboratory of Lausanne, Switzerland. Recent research utilizing the Western blot technique showed an improved detection of EPO in blood and urine based on novel Velum SAR precast horizontal gels optimized for routine analysis.
=== Glucagon === Glucagon is a hormone that rapidly counters the metabolic effects of insulin in the liver, causing glycogenolysis and release of glucose into the blood. It can raise the glucose by 30–100 mg/dL within minutes in any form of hypoglycemia caused by insulin excess (including all types of diabetic hypoglycemia). It comes in a glucagon emergency rescue kit which includes tiny vials containing 1 mg, which is a standard adult dose. The glucagon in the vial is a lyophilized pellet, which must be reconstituted with 1 mL of sterile water, included in the "kit". In the widely used Lilly Emergency Kit, the water is contained in a syringe with a large needle for intramuscular injection and must be injected into the vial with the pellet of glucagon before being injected. Glucagon works if given subcutaneously, but absorption and recovery are faster if it is injected deep into a muscle (usually the middle of the outside of the thigh). It has an even more rapid effect when given intravenously but this is rarely practicable. Side effects of glucagon can include nausea and headache, but these can also occur after severe hypoglycemia even when glucagon is not used. Risks of glucagon use are far lower than risks of severe hypoglycemia, and it can usually produce a faster recovery than calling for paramedics and waiting for them to start an intravenous line to give dextrose. If someone uses this kit, they should be seen in an emergency room, as glucagon depletes glycogen stores, and can lead to a deadly rebound hypoglycemia.
Sources: en.wikipedia.org
2-Oxoadipic acid, also known as α-ketoadipic acid, is an intermediate in the metabolism of lysine and tryptophan. The conjugate base and carboxylate is 2-oxoadipate or α-ketoadipate, which is the biochemically relevant form. Glutaric acid is naturally produced by chain extension of α-ketoglutarate to 2-oxoadipic acid.
== External links == "P2Y Receptors: P2Y11". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2008-12-09. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
=== Sequence-based methods === Prime, NetMHCpan, MHCnuggets, MHCflurry, DeepNeo, and BigMHC are among the most popular methods to predict peptide-MHC immunogenicity from protein amino acid sequences. They essentially parse the protein sequences as text data, using 1-dimensional convolutional neural networks, recurrent neural networks, or Transformer models.
Santosh Shivaji Lad (born 27 February 1975) is an Indian politician from Karnataka and a member of the Indian National Congress. He has been elected to the Karnataka Legislative Assembly four times, first from Sandur in 2004 and subsequently from Kalaghatgi in 2008, 2013 and 2023. He currently serves as the Cabinet Minister for Labour and Employment in Government of Karnataka, and is a member of Karnataka Legislative Assembly representing Kalaghatgi-Alnavar constituency in the Dharwad district of Karnataka state. Lad has served as a minister in successive Karnataka governments. He served as Minister of State for Information and Infrastructure Development in the Siddaramaiah ministry from 2013, resigned from the ministry in November 2013 following allegations concerning illegal mining involving his company, and returned to the state cabinet in 2016 as Labour Minister, later also holding the Skill Development portfolio.
Sources: en.wikipedia.org
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.