If you have been reading about 甲硫氨酸氧化 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.
Updated 2025-08-27. Numbers and descriptions here follow the published literature rather than marketing material.
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。
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 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.
| Property | Value | Notes |
|---|---|---|
| 分子式 | C37H51N9O10S | 游离碱形式 |
| 等电点 | 约 6.5 | 估算值，随缓冲体系变化 |
| 主要降解途径 | 水解与氧化 | 侧链氧化最为常见 |
| 溶液储存 | 2 至 8 摄氏度避光 | 避免反复冻融 |
| 常规分析手段 | 反相色谱与质谱联用 | 氨基酸分析辅助核对 |
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.
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.
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.
Top-icing is the practice of placing a 2-inch (51 mm) to 4-inch (100 mm) layer of crushed ice on top of agricultural products that have high respiration rates, need high relative humidity, and benefit from having the cooling agent sit directly atop the load (or within individual boxes). Cars with pre-cooled fresh produce were top-iced just before shipment. Top-icing added considerable dead weight to the load. Top-icing a 40-foot (12 m) reefer required in excess of 10,000 pounds (4,500 kg) of ice. It had been postulated that as the ice melted, the resulting chilled water would trickle down through the load, continuing the cooling process. It was found, however, that top-icing benefited only the uppermost layers of the cargo, and that the water from melting ice often passed through spaces between the cartons and pallets, with little or no cooling effect. It was ultimately determined that top-icing is useful only in preventing an increase in temperature and was eventually discontinued.
is the Fermi energy). The kinetic inductance, representing the collective inertial effect, is intimately linked to graphene plasmonics, and was directly measured via microwave network analysis in 2014.
He will be part of the wound healing and offloading working groups for the 2023 update. Viswanathan currently serves as national president of the Research Society for the Study of Diabetes in India (RSSDI). On 30 March 2024, MV Hospital for Diabetes and the Prof. M. Viswanathan Diabetes Research Centre, Royapuram, conducted the 38th Prof. M. Viswanathan DRC Gold Medal Oration in Chennai. During the event, the hospital launched a 'Wound Clinic Training Program' designed to educate healthcare professionals on preventing complications associated with diabetic foot infections. In October 2024, MV Hospital for Diabetes, in collaboration with the Academy of Physicians in Wound Healing (United States), established a School of Podiatry under the name Diabetic Foot Research India, aimed at providing training in podiatric care for medical and paramedical professionals.
Tube lubrication: The surface of the bar or tube is coated with a drawing lubricant such as phosphate or oil to aid cold drawing. Push pointing: Several inches of the lead ends of the bar or tube are reduced in size by swaging or extruding so that it can pass freely through the drawing die. This is done because the die opening is always smaller in size than the original bar or coil section. Cold drawing, process drawing: In this process, the material is drawn at room temperature. The reduced end of the bar or coil, which is smaller than the die opening, is passed through the die where it enters a gripping device of the drawing machine. The drawing machine pulls ("draws") the remaining unreduced section of the bar or coil through the die. The die reduces the cross section of the bar or coil, shapes its profile, and increases its length. Finished product: The drawn product, which is referred to as "cold drawn" or "cold finished", exhibits a bright or polished finish, increased mechanical properties, improved machining characteristics, and precise and uniform dimensional tolerances. Multi-pass drawing: The cold drawing of complex shapes or profiles may involve the workpiece being drawn multiple times through progressively smaller die openings in order to produce the desired shape and tolerances. Material is generally annealed between each drawing pass to increase its ductility and remove internal stresses produced during the cold working.
Sources: en.wikipedia.org
=== Fluid replacement === The amount of fluid replaced depends on the estimated degree of dehydration. If dehydration is so severe as to cause shock (severely decreased blood pressure with insufficient blood supply to the body's organs), or a depressed level of consciousness, rapid infusion of saline (1 liter for adults, 10 mL/kg in repeated doses for children) is recommended to restore circulating volume. Slower rehydration based on calculated water and sodium shortage may be possible if the dehydration is moderate, and again saline is the recommended fluid. Very mild ketoacidosis with no associated vomiting and mild dehydration may be treated with oral rehydration and subcutaneous rather than intravenous insulin under observation for signs of deterioration. Normal saline (0.9% saline) has generally been the fluid of choice. There have been a few small trials looking at balanced fluids with few differences. A special but unusual consideration is cardiogenic shock, where the blood pressure is decreased not due to dehydration but due to the inability of the heart to pump blood through the blood vessels. This situation requires ICU admission, monitoring of the central venous pressure (which requires the insertion of a central venous catheter in a large upper body vein), and the administration of medication that increases the heart pumping action and blood pressure.
== Function == The melanocortin system is one of the mammalian body's tools to regulate food intake in a push-pull fashion. The only neurons known to release melanocortins are located in the arcuate nucleus of the hypothalamus. However, melanocortins are also produced by keratinocytes in response to UV exposure. Accordingly, there is a subpopulation called POMC neurons and one called AgRP neurons. When POMC neurons release α-MSH, appetite is decreased. On the other hand, when AgRP neurons release AgRP, appetite is stimulated. Leptin, the energy surfeit hormone, and Ghrelin, the hunger hormone, are upstream regulators of the melanocortin system in the brain. These hormones also regulate the release of peptides other than the melanocortins. Disturbance of the leptin-melanocortin pathway can lead to early onset obesity as well as various metabolic disorders and suppressed immune function.
The side effects of ketoconazole are sometimes harnessed in the treatment of non-fungal conditions. While ketoconazole blocks the synthesis of the sterol ergosterol in fungi, in humans, at high dosages (>800 mg/day), it potently inhibits the activity of several enzymes necessary for the conversion of cholesterol to steroid hormones such as testosterone and cortisol. Specifically, ketoconazole has been shown to inhibit cholesterol side-chain cleavage enzyme, which converts cholesterol to pregnenolone, 17α-hydroxylase and 17,20-lyase, which convert pregnenolone into androgens, and 11β-hydroxylase, which converts 11-deoxycortisol to cortisol. All of these enzymes are mitochondrial cytochrome p450 enzymes. Based on these antiandrogen and antiglucocorticoid effects, ketoconazole has been used with some success as a second-line treatment for certain forms of advanced prostate cancer and for the suppression of glucocorticoid synthesis in the treatment of Cushing's syndrome. However, in the treatment of prostate cancer, concomitant glucocorticoid administration is needed to prevent adrenal insufficiency. Ketoconazole has additionally been used, in lower dosages, to treat hirsutism and, in combination with a GnRH analogue, male-limited precocious puberty. In any case, the risk of hepatotoxicity with ketoconazole limits its use in all of these indications, especially in those that are benign such as hirsutism. Ketoconazole has been used to prevent the testosterone flare at the initiation of GnRH agonist therapy in men with prostate cancer.
Sources: en.wikipedia.org
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。
甲硫氨酸侧链含硫醚，在氧气、光照或金属离子存在时容易被氧化。氧化产物极性略增，常在色谱图上表现为主峰之前的肩峰或前伸峰。
通常建议冷藏避光，并在较短时间内使用。不存在适用于所有配方的统一期限，具体取决于浓度、缓冲体系与容器材质。
It is a short synthetic peptide built from seven amino acids: methionine, glutamic acid, histidine, phenylalanine and three prolines. The sequence derives from the 4-10 fragment of adrenocorticotropic hormone with an added proline-glycine-proline tail. No plant or animal extract is involved; the material is produced by solid-phase peptide synthesis.