methionine sulfoxide comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Last reviewed on 2026-07-18. Where a claim depends on a specific study, the study is described rather than over-claimed.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
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.
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。
Among the earliest reports of MOF-based catalysis was the cyanosilylation of aldehydes by a 2D MOF (layered square grids) of formula Cd(4,4′-bpy)2(NO3)2. This investigation centered mainly on size- and shape-selective clathration. A second set of examples was based on a two-dimensional, square-grid MOF containing single Pd(II) ions as nodes and 2-hydroxypyrimidinolates as struts. Despite initial coordinative saturation, the palladium centers in this MOF catalyze alcohol oxidation, olefin hydrogenation, and Suzuki C–C coupling. At a minimum, these reactions necessarily entail redox oscillations of the metal nodes between Pd(II) and Pd(0) intermediates accompanying by drastic changes in coordination number, which would certainly lead to destabilization and potential destruction of the original framework if all the Pd centers are catalytically active. The observation of substrate shape- and size-selectivity implies that the catalytic reactions are heterogeneous and are indeed occurring within the MOF. Nevertheless, at least for hydrogenation, it is difficult to rule out the possibility that catalysis is occurring at the surface of MOF-encapsulated palladium clusters/nanoparticles (i.e., partial decomposition sites) or defect sites, rather than at transiently labile, but otherwise intact, single-atom MOF nodes. "Opportunistic" MOF-based catalysis has been described for the cubic compound, MOF-5.
== Other early lodges == On April 15, 1820, Cubans received news that Rafael del Riego and his Liberal constitutionalist movement was triumphant in Spain. Juan Manuel de Cagigal publicly swore his allegiance to the 1812 Constitution, after being forced to do so by regiments of the Spanish Army from Málaga and Catalonia. Only days after the announcement of the new situation in Spain, several Masonic Lodges and other secret societies that had been operating in secret began operating openly. They had large numbers, and during the era of the Liberal Triennium, they took advantage of the situation to establish more lodges.
== Pathophysiology == Chronic wounds may affect only the epidermis and dermis, or they may affect tissues all the way to the fascia. They may be formed originally by the same things that cause acute ones, such as surgery or accidental trauma, or they may form as the result of systemic infection, vascular, immune, or nerve insufficiency, or comorbidities such as neoplasias or metabolic disorders. The reason a wound becomes chronic is that the body's ability to deal with the damage is overwhelmed by factors such as repeated trauma, continued pressure, ischemia, or illness. Though much progress has been accomplished in the study of chronic wounds lately, advances in the study of their healing have lagged behind expectations. This is partly because animal studies are difficult because animals do not get chronic wounds, since they usually have loose skin that quickly contracts, and they normally do not get old enough or have contributing diseases such as neuropathy or chronic debilitating illnesses. Nonetheless, current researchers now understand some of the major factors that lead to chronic wounds, among which are ischemia, reperfusion injury, and bacterial colonization.
Reaction to the poem has been mixed. Although its authenticity has been doubted from the beginning, some claimed that it was an "insight" of Li Bai who would foresee the war crime of Japan. Some Chinese felt disgraced by the humor, and blamed the author was so childish and shameful to imitate Li Bai in a bad taste apocryphal poem. However, most people simply took it as a joke.
Sources: en.wikipedia.org
== Emergencies == As the complete cross-matching process takes approximately 1 hour, it is not always used in emergencies. In the case of an emergency, a type-specific blood to which the recipient has no antibodies, can be requested. It is thought that this lifesaving measure is of more benefit than any risk of an antibody-mediated transfusion reaction. This type of blood has less risk of a serious transfusion reaction because it is both ABO compatible and Rhesus (Rh)-compatible. Universal donor blood, which is both type O and Rh negative, can be given if the recipient's blood group is not known, as may happen in an emergency. It is the policy of some institutions to reserve the releasing of O− blood only for female patients of childbearing age. This serves two purposes. First, it preserves the lower stock of O− blood and secondly, this eliminates the risk of O− negative mothers forming anti-D (Rh) antibodies from exposure to O+ blood. Anti-D (Rh) can cross the placenta during pregnancy and attack an unborn child's RBCs if they are D (Rh) positive causing haemolytic disease of the newborn. In an emergency, blood grouping can be done easily and quickly in 2 or 3 minutes in the laboratory on glass slides with appropriate reagents, by trained technical staff. This method depends on the presence or absence of agglutination (clumping of red blood cells), which can usually be visualized directly. Presence of agglutination indicates incompatibility. Occasionally a light microscope may be needed.
== External links == International Chemical Safety Card 0457 NIOSH Pocket Guide to Chemical Hazards. "#0226". National Institute for Occupational Safety and Health (NIOSH). Concise International Chemical Assessment Document 31: N,N-Dimethylformamide
Emoxypine inhibits oxidation of biomembrane lipids. Increases the activity of antioxidant enzymes, specifically that of superoxide dismutase, responsible for the formation and consumption of lipid peroxides and active oxygen forms. Inhibits free radicals during the synthesis of prostaglandin catalyzed cyclooxygenase and lipoxygenase, increases the correlation prostacyclin/ thromboxane A2 and blocks the leukotriene formation. Increases the content of polar fraction of lipids (phosphatidyl serine and phosphatidyl inositol) and reduces the cholesterol/phospholipids ratio which proves its lipid-regulatory properties; shifts structure transition into the low temperature zones, that is provokes the reduction of membrane viscosity and the increase of its fluidity, increases lipid-protein ratio. Modulates the activity of membrane-bound enzymes: phosphodiesterase, cyclic nucleotides, adenylate cyclase, aldoreductase, acetylcholinesterase. Modulates the receptor complexes of the brain membranes, i.e. benzodiazepine, GABA, acetylcholine receptors by increasing their binding ability. Stabilizes biomembranes, i.e. membrane structures of blood cells - erythrocytes and thrombocytes during their haemolysis or mechanical injury accompanied by the formation of free radicals. Changes the monoamine level and increases the dopamine content in the brain. Still, the antioxidant and membrane-protective effects have not been proven in reviews and meta-analyses.
== Mechanism of action == Azacitidine is a chemical analogue of the nucleoside cytidine, which is present in DNA and RNA. It is thought to have antineoplastic activity via two mechanisms – at low doses, by inhibiting of DNA methyltransferase, causing hypomethylation of DNA, and at high doses, by its direct cytotoxicity to abnormal hematopoietic cells in the bone marrow through its incorporation into DNA and RNA, resulting in cell death. Azacitidine is a ribonucleoside, so it is incorporated into RNA to a larger extent than into DNA. In contrast, decitabine (5-aza-2'-deoxycytidine) is a deoxyribonucleoside, so it can only incorporate into DNA. Azacitidine's incorporation into RNA leads to the disassembly of polyribosomes, defective methylation and acceptor function of transfer RNA, and inhibition of the production of proteins. Its incorporation into DNA leads to covalent binding with DNA methyltransferases, which prevents DNA synthesis and subsequently leads to cytotoxicity. It has been shown effective against human immunodeficiency virus in vitro and human T-lymphotropic virus.
== Production == 5-HTP is produced from the amino acid tryptophan through the action of the enzyme tryptophan hydroxylase. Tryptophan hydroxylase is one of the biopterin-dependent aromatic amino acid hydroxylases. Production of 5-HTP is the rate-limiting step in 5-HT (serotonin) synthesis. 5-HTP is normally rapidly converted to 5-HT by amino acid decarboxylase.
Sources: en.wikipedia.org
He was one of the main leaders of the Military Union, which took participation in the 1923 coup d'état. He was also in the home of Ivan Rusev during the night of the coup. He was an active role in the unification of parties to create the Democratic Alliance. In October, he participated in the negotiations for the creation of an electoral coalition with the Bulgarian Workers' Social Democratic Party (broad socialists), and in the elections of 18 November he was elected deputy from the Sofia Rural Collegium. In April 1925, Georgiev attended the funeral of retired General Konstantin Georgiev, a deputy and chairman of the Sofia organization of the Democratic Union and garrison leader of the Military Union, and was wounded in the St Nedelya Church assault. In an article dedicated to Nikola Rachev, who died in the blast, he called the bombers "freaks" preparing a "death blow" against Bulgaria. Later that year, he was sent to Pirin as a government representative during the Incident at Petrich.
The three substrates of this enzyme are (R)-β-alanopine, oxidised nicotinamide adenine dinucleotide (NAD+), and water. Its products are β-alanine, reduced NADH, pyruvic acid and a proton. β-alanopine is a type of opine. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is N-(D-1-carboxyethyl)-beta-alanine:NAD+ oxidoreductase (beta-alanine-forming).
wstd: weight of internal standard wspl: weight of sample n[H]std: the integrated area of the peak selected for comparison in the standard, corrected for the number of protons in that functional group n[H]spl: the integrated area of the peak selected for comparison in the sample, corrected for the number of protons in that functional group MWstd: molecular weight of standard MWspl: molecular weight of sample P: purity of internal standard
== Biological significance == Steroids and their metabolites are often signalling molecules (the most notable examples are steroid hormones), and steroids and phospholipids are components of cell membranes. Steroids such as cholesterol decrease membrane fluidity. Similar to lipids, steroids are highly concentrated energy stores. However, they are not typically sources of energy; in mammals, they are normally metabolized and excreted. Steroids play critical roles in a number of disorders, including malignancies like prostate cancer, where steroid production inside and outside the tumor promotes cancer cell aggressiveness.
The election of Abraham Lincoln in 1860 drastically intensified the secession debate in Knoxville, and the city's leaders met on November 26 to discuss the issue. Those who favored secession, such as J.G.M. Ramsey, believed it was the only way to ensure the rights of Southerners. Those who rejected secession, such as Maynard and Temple, believed that East Tennesseans, most of whom were yeoman farmers, would be rendered subservient to a government dominated by Southern planters. In February 1861, Tennessee held a vote on whether or not to hold a statewide convention to consider seceding and joining the Confederacy. In Knoxville, 77% voted against this measure, affirming the city's allegiance to the Union. Throughout the first half of 1861, Brownlow and J. Austin Sperry (the radical secessionist editor of the Knoxville Register) assailed one another mercilessly in their respective papers, and Union and Secessionist leaders blasted one another in speeches across the region. Simultaneous Union and Confederate recruiting rallies were held on Gay Street. Following the attack on Fort Sumter in April, Governor Isham Harris made moves to align the state with the Confederacy, prompting the region's Unionists to form the East Tennessee Convention, which met at Knoxville on May 30, 1861. The convention submitted a petition to Governor Isham Harris, calling his actions undemocratic and unconstitutional.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.