This is a working overview of Oxidation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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。
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
Later generations of the molecule include an N-acetylated form and an amidated form, both marketed online alongside the parent peptide. These variants differ in terminal chemistry and stability, and they are frequently discussed in the same breath even though they have not been compared in controlled trials. Supply outside formal healthcare systems comes largely from laboratories that synthesize peptides to order. Purity and identity of these materials vary widely, and no single body oversees the international trade.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
| 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 |
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
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.
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.
Freeze-drying – the Andean civilizations learned to freeze dry potatoes (chuño) and other food items, so that the resultant dehydrated powder could be stored for years and then later transported across vast distances to feed countless peoples. The Spanish conquistadors used this Andean invented freeze-drying technique to transport several tonnes of dehydrated potatoes across the Atlantic Ocean back to Europe to feed Europeans.
=== EC 2.7.8: Transferases for other substituted phosphate groups === EC 2.7.8.1: diacylglycerol ethanolaminephosphotransferase EC 2.7.8.2: diacylglycerol cholinephosphotransferase EC 2.7.8.3: ceramide cholinephosphotransferase EC 2.7.8.4: serine ethanolaminephosphotransferase EC 2.7.8.5: CDP-diacylglycerol—glycerol-3-phosphate 1-phosphatidyltransferase EC 2.7.8.6: undecaprenyl-phosphate galactose phosphotransferase EC 2.7.8.7: holo-[acyl-carrier-protein] synthase EC 2.7.8.8: CDP-diacylglycerol—serine O-phosphatidyltransferase EC 2.7.8.9: phosphomannan mannosephosphotransferase EC 2.7.8.10: sphingosine cholinephosphotransferase EC 2.7.8.11: CDP-diacylglycerol—inositol 3-phosphatidyltransferase EC 2.7.8.12: CDP-glycerol glycerophosphotransferase EC 2.7.8.13: phospho-N-acetylmuramoyl-pentapeptide-transferase EC 2.7.8.14: CDP-ribitol ribitolphosphotransferase EC 2.7.8.15: UDP-N-acetylglucosamine—dolichyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.16: deleted, now included with EC 2.7.8.2 diacylglycerol cholinephosphotransferase EC 2.7.8.17: UDP-N-acetylglucosamine—lysosomal-enzyme N-acetylglucosaminephosphotransferase EC 2.7.8.18: UDP-galactose—UDP-N-acetylglucosamine galactose phosphotransferase EC 2.7.8.19: UDP-glucose—glycoprotein glucose phosphotransferase EC 2.7.8.20: phosphatidylglycerol—membrane-oligosaccharide glycerophosphotransferase EC 2.7.8.21: membrane-oligosaccharide glycerophosphotransferase EC 2.7.8.22: 1-alkenyl-2-acylglycerol choline phosphotransferase EC 2.7.8.23: carboxyvinyl-carboxyphosphonate phosphorylmutase EC 2.7.8.24: CDP-diacylglycerol—choline O-phosphatidyltransferase EC 2.7.8.25: Now EC 2.4.2.52, triphosphoribosyl-dephospho-CoA synthase EC 2.7.8.26: adenosylcobinamide-GDP ribazoletransferase EC 2.7.8.27: sphingomyelin synthase EC 2.7.8.28: 2-phospho-L-lactate transferase EC 2.7.8.29: L-serine-phosphatidylethanolamine phosphatidyltransferase EC 2.7.8.30: Now EC 2.4.2.53, undecaprenyl-phosphate 4-deoxy-4-formamido-L-arabinose transferase EC 2.7.8.31: undecaprenyl-phosphate glucose phosphotransferase EC 2.7.8.32: 3-O-α-D-mannopyranosyl-α-D-mannopyranose xylosylphosphotransferase EC 2.7.8.33: UDP-N-acetylglucosamine—undecaprenyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.34: CDP-L-myo-inositol myo-inositolphosphotransferase EC 2.7.8.35: UDP-N-acetylglucosamine—decaprenyl-phosphate N-acetylglucosaminephosphotransferase EC 2.7.8.36: undecaprenyl phosphate N,N′-diacetylbacillosamine 1-phosphate transferase EC 2.7.8.37: α-D-ribose 1-methylphosphonate 5-triphosphate synthase EC 2.7.8.38: archaetidylserine synthase EC 2.7.8.39: archaetidylinositol phosphate synthase EC 2.7.8.40: UDP-N-acetylgalactosamine-undecaprenyl-phosphate N-acetylgalactosaminephosphotransferase EC 2.7.8.41: cardiolipin synthase (CMP-forming) EC 2.7.8.42: Kdo2-lipid A phosphoethanolamine 7′′-transferase EC 2.7.8.43: lipid A phosphoethanolamine transferase EC 2.7.8.44: teichoic acid glycerol-phosphate primase EC 2.7.8.45: teichoic acid glycerol-phosphate transferase EC 2.7.8.46: teichoic acid ribitol-phosphate primase EC 2.7.8.47: teichoic acid ribitol-phosphate polymerase
=== Leadership === Roger D. Cone began his tenure as the Mary Sue Coleman Director of the University of Michigan Life Sciences Institute in September 2016. A leading researcher in brain regulation of body weight, Cone also serves as vice provost and director of U-M's biosciences initiative. The managing director is Anna Schork. The institute's first director was Jack E. Dixon. In 2002, Mary Sue Coleman, U-M's president, appointed cell biologist and expert on insulin signaling Alan R. Saltiel as director. Saltiel served as the director until 2015, followed by interim director Stephen Weiss, who led the institute from 2015 to 2016.
=== Appearance === Color: LEDs can emit light of an intended color without using any color filters as traditional lighting methods need. This is more efficient and can lower initial costs. Cool light: In contrast to most light sources, LEDs radiate very little heat in the form of IR that can cause damage to sensitive objects or fabrics. Wasted energy is dispersed as heat through the base of the LED. Color rendition: Most cool-white LEDs have spectra that differ significantly from a black body radiator like the sun or an incandescent light. The spike at 460 nm and dip at 500 nm can make the color of objects appear differently under cool-white LED illumination than sunlight or incandescent sources, due to metamerism, red surfaces being rendered particularly poorly by typical phosphor-based cool-white LEDs. The same is true with green surfaces. The quality of color rendition of an LED is measured by the Color Rendering Index (CRI). Dimming: LEDs can be dimmed either by pulse-width modulation or lowering the forward current. This pulse-width modulation is why LED lights, particularly headlights on cars, when viewed on camera or by some people, seem to flash or flicker. This is a type of stroboscopic effect.
Sources: en.wikipedia.org
=== Nigeria === In Nigeria, medical laboratory science is a high skilled profession charged by Act 11 of 2003 Laws of the Federation of Nigeria. The initial qualification awarded graduates of the programme, like some other medical programmes, was Associate of the Institute of Medical Laboratory Technology/Science (AIMLT/AIMLS). The Medical Laboratory Science Council of Nigeria, which was established by Act. 2004 Cap 114 Laws of the Federation of Nigeria, regulates the practice of medical laboratory science in Nigeria. In Nigeria, the Medical Laboratory Science programme is Bachelor of Medical Laboratory Science (BMLS), regulated by the National Universities Commission (NUC) and the Medical Laboratory Science Council of Nigeria (MLSCN). Students at their first year (100 level) are trained under the Faculty of Science in Basic Sciences and Faculty of Arts, Management and Social science in General studies and Entrepreneurship. At the 200 level, students are taught basic medical sciences and are introduced to Medical Laboratory Science. The third year of the programme marks the beginning of the professional training as students are engaged in the classroom for lectures as well as in the Hospital laboratory for the professional or practical training. At the fourth year, students are taught the basics in all the special areas of medical laboratory science. At the end of 400 level programme, successful students are presented for the first professional examination, to be moderated by the Medical Laboratory Science Council of Nigeria.
Carbodiimide activation opens the possibility for racemization of the activated amino acid. Racemization can be circumvented with 'racemization suppressing' additives such as the triazoles 1-hydroxy-benzotriazole (HOBt), and 1-hydroxy-7-aza-benzotriazole (HOAt). These reagents attack the O-acylisourea intermediate to form an active ester, which subsequently reacts with the peptide to form the desired peptide bond. Ethyl cyanohydroxyiminoacetate (Oxyma), an additive for carbodiimide coupling, acts as an alternative to HOAt.
Histology image: 08008loa – Histology Learning System at Boston University Atlas image: eye_1 at the University of Michigan Health System—"Sagittal Section Through the Eyeball" MedlinePlus Encyclopedia: 002295
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 originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.