If you have been reading about Methionine oxidation and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2025-09-05. Where a claim depends on a specific study, the study is described rather than over-claimed.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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.
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.
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 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.
Pakistan and Bangladesh have experienced strained relations, particularly under the Awami League governments led by Sheikh Hasina, driven by her pro-India stance and historical grievances. Pakistan, a prominent member of the Organisation of Islamic Cooperation (OIC), prioritises maintaining cultural, political, social, and economic relations with Arab and other Muslim-majority nations in its foreign policy. In September 2025, Pakistan and Saudi Arabia signed a Strategic Mutual Defence Agreement under which any aggression against one country is considered an aggression against both, formalising a defensive commitment that also extends Pakistan's nuclear umbrella to Saudi Arabia.
This process through which perceived inferiority can be exercised physically can be looked back on through a foundational perspective of the "Nigrescence Theory". This theory explains the distinction of one's own socialized identity through various stages, and the pigmentation of the skin that someone is born with that is associated with the socialization process within a culture. More specifically, out of the four stages associated with this theory, the first one, named the "pre-encounter" stage, highlights the underlying concept one not associating themselves with their own culture or values due partly to the misinformation one has been taught to believe and therefore seeks validation and worthiness from those who have misinformed that person.
The breast augmentation patient usually is a young woman whose personality profile indicates psychological distress about her personal appearance and her bodily self image, and a history of having endured criticism (teasing) about the aesthetics of her person. The studies Body Image Concerns of Breast Augmentation Patients (2003) and Body Dysmorphic Disorder and Cosmetic Surgery (2006) reported that the woman who underwent breast augmentation surgery also had undergone psychotherapy, suffered low self-esteem, presented frequent occurrences of psychological depression, had attempted suicide, and had body dysmorphia, a type of mental illness. Post-operative patient surveys about mental health and quality-of-life, reported improved physical health, physical appearance, social life, self-confidence, self-esteem, and satisfactory sexual functioning. Furthermore, the women reported long-term satisfaction with their breast implant outcomes; some despite having medical complications that required surgical revision, either corrective or aesthetic. Likewise, in Denmark, 8% of breast augmentation patients had a pre-operative history of psychiatric hospitalization. In 2008, the longitudinal study Excess Mortality from Suicide and other External Causes of Death Among Women with Cosmetic Breast Implants (2007), reported that women who sought breast implants are almost 3 times as likely to commit suicide as are women who have not sought breast implants.
Sources: en.wikipedia.org
== Classification == The MEROPS protease classification system counts 14 superfamilies plus several currently unassigned families (as of 2013) each containing many families. Each superfamily uses the catalytic triad or dyad in a different protein fold and so represent convergent evolution of the catalytic mechanism. For superfamilies, P indicates a superfamily containing a mixture of nucleophile class families, and C indicates purely cysteine proteases. Within each superfamily, families are designated by their catalytic nucleophile (C denoting cysteine proteases).
The late 20th century also saw an expansion of the application of analytical chemistry from somewhat academic chemical questions to forensic, environmental, industrial and medical questions, such as in histology. Modern analytical chemistry is dominated by instrumental analysis. Many analytical chemists focus on a single type of instrument. Academics tend to either focus on new applications and discoveries or on new methods of analysis. The discovery of a chemical present in blood that increases the risk of cancer would be a discovery that an analytical chemist might be involved in. An effort to develop a new method might involve the use of a tunable laser to increase the specificity and sensitivity of a spectrometric method. Many methods, once developed, are kept purposely static so that data can be compared over long periods of time. This is particularly true in industrial quality assurance (QA), forensic, and environmental applications. Analytical chemistry plays an increasingly important role in the pharmaceutical industry where, aside from QA, it is used in the discovery of new drug candidates and in clinical applications where understanding the interactions between the drug and the patient are critical. The 21st century has been defined by the digitalization of analytical chemistry. The handling of large datasets ("big data") from instruments like Orbitrap mass spectrometers has made advanced data analysis, including machine learning, an essential skill.
Hydrolysis and oxidation are the two primary degradation processes that occur in an oil during cooking. Oxidative stability is how resistant an oil is to reacting with oxygen, breaking down and potentially producing harmful compounds while exposed to continuous heat. Oxidative stability is the best predictor of how an oil behaves during cooking. The Rancimat method is one of the most common methods for testing oxidative stability in oils. This determination entails speeding up the oxidation process in the oil (under heat and forced air), which enables its stability to be evaluated by monitoring volatile substances associated with rancidity. It is measured as "induction time" and recorded as total hours before the oil breaks down. Canola oil requires 7.5 hours, for example, whereas extra virgin olive oil (EVOO) and virgin coconut oil will last over a day at 110 °C (230 °F) of continuous heat. The differing stabilities correlate with lower levels of polyunsaturated fatty acids, which are more prone to oxidation. EVOO is high in monounsaturated fatty acids and antioxidants, conferring stability. Some plant cultivars have been bred to produce "high-oleic" oils with more monounsaturated oleic acid and less polyunsaturated linoleic acid for enhanced stability. The oxidative stability does not directly correspond to the smoke point and thus the latter cannot be used as a reference for safe and healthy cooking.
Sources: en.wikipedia.org
=== Angevin transition === After the Polish royal line and Piast junior branch died out in 1370, Poland came under the rule of Louis I of Hungary of the Capetian House of Anjou, who presided over a union of Hungary and Poland that lasted until 1382. In 1374, Louis granted the Polish nobility the Privilege of Koszyce to assure the succession of one of his daughters in Poland. His youngest daughter Jadwiga (d. 1399) assumed the Polish throne in 1384.
If silver or white (Blanco) tequila is the desired final product, distillation is the final process it undergoes. Rested (Reposado) or aged (Añejo) tequila must be matured in 200-liter (or larger) white oak barrels for at least two months for the former and 12 months for the latter. The newest category of tequila classification, extra añejo, must be aged for at least three years in oak barrels. There are, however, more than 50 different companies producing tequila in the Mexican state of Jalisco, with different maturation times according to the variety of tequila and desired quality of the final product. All companies producing tequila have their aging processes regulated and fiscalized by the Mexican government.
=== Myocardium / cardiomyopathy === (I40) Acute myocarditis (I41) Myocarditis in diseases classified elsewhere (I42) Cardiomyopathy (I42.0) Dilated cardiomyopathy (I42.1) Obstructive hypertrophy cardiomyopathy (I42.2) Other hypertrophic cardiomyopathy (I42.3) Endomyocardial (eosinophilic) disease Eosinophilic myocarditis Endomyocardial (tropical) fibrosis Löffler's endocarditis (I42.4) Endocardial fibroelastosis (I42.5) Other restrictive cardiomyopathy (I42.6) Alcoholic cardiomyopathy (I42.8) Other cardiomyopathies Arrhythmogenic right ventricular dysplasia (I43) Cardiomyopathy in diseases classified elsewhere
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。