heptapeptide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-01-30 and is reviewed periodically as new material appears.
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。
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.
| 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 |
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。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
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.
=== EC 1.7.3 With oxygen as acceptor === EC 1.7.3.1: nitroalkane oxidase EC 1.7.3.2: acetylindoxyl oxidase EC 1.7.3.3: factor-independent urate hydroxylase EC 1.7.3.4: Now covered by EC 1.7.2.6, hydroxylamine dehydrogenase, and EC 1.7.3.6, hydroxylamine oxidase (cytochrome) EC 1.7.3.5: 3-aci-nitropropanoate oxidase EC 1.7.3.6: hydroxylamine oxidase (cytochrome)
Fibromas are benign tumors that are composed of fibrous or connective tissue. They can grow in all organs, arising from mesenchyme tissue. The term "fibroblastic" or "fibromatous" is used to describe tumors of the fibrous connective tissue. When the term fibroma is used without modifier, it is usually considered benign, with the term fibrosarcoma reserved for malignant tumors.
Depolarization opens both the sodium and potassium channels in the membrane, allowing the ions to flow into and out of the axon, respectively. If the depolarization is small (say, increasing Vm from −70 mV to −60 mV), the outward potassium current overwhelms the inward sodium current and the membrane repolarizes back to its normal resting potential around −70 mV. However, if the depolarization is large enough, the inward sodium current increases more than the outward potassium current and a runaway condition (positive feedback) results: the more inward current there is, the more Vm increases, which in turn further increases the inward current. A sufficiently strong depolarization (increase in Vm) causes the voltage-sensitive sodium channels to open; the increasing permeability to sodium drives Vm closer to the sodium equilibrium voltage ENa≈ +55 mV. The increasing voltage in turn causes even more sodium channels to open, which pushes Vm still further towards ENa. This positive feedback continues until the sodium channels are fully open and Vm is close to ENa. The sharp rise in Vm and sodium permeability correspond to the rising phase of the action potential. The critical threshold voltage for this runaway condition is usually around −45 mV, but it depends on the recent activity of the axon. A cell that has just fired an action potential cannot fire another one immediately, since the Na+ channels have not recovered from the inactivated state. The period during which no new action potential can be fired is called the absolute refractory period.
Xi has called traditional Chinese culture the "soul" of the nation and the "foundation" of the CCP's culture. He has praised the "splendid Chinese civilization", calling the CCP's governance part of "the uninterrupted development of a civilization for several thousand years" which is "rarely seen among nations in the world". Xi has also called for integrating the basic tenets of Marxism with China's traditional culture. He has established the "Four Confidences", which has later been added to the CCP constitution, calling for CCP members, government officials and the Chinese people to be "confident in our chosen path, confident in our guiding theories, confident in our political system, and confident in our culture." He unveiled Global Civilization Initiative in 2023, calling for "respecting the diversity of civilizations, advocating the common values of humanity, valuing the inheritance and innovation of civilizations, and strengthening international people-to-people exchanges and cooperation".
Sources: en.wikipedia.org
Treatment of depression: Used in adults who may present with symptoms of anxiety, low mood, lack of enthusiasm, and restlessness. Treatment of anxiety: Indicated for patients with anxiety disorders, especially when depression is also present or when there is associated asthenia (unexplained fatigue or weakness). Management of asthenia: Used for conditions characterized by fatigue, low energy, and diminished motivation, frequently seen with mood disturbances. Psychosomatic and neurotic disorders: Recommended for depressive neuroses, psychogenic depression, masked depression, neurasthenia, and psychosomatic affections where anxiety, depression, or apathy are prominent. Menopausal depression: Often indicated for mood changes associated with menopause. Depression in alcoholics and drug addicts: Used in cases where mood disorders accompany substance dependence.
== Dysfunction == Impaired sudomotor function can occur in any disorder that directly and/or indirectly affects the autonomic nervous system, including diabetes mellitus, amyloidosis, infections, neurodegenerative diseases, multiple system atrophy, and pure autonomic failure. Sudomotor dysfunction can manifest as increased or decreased sweating patterns. Both patterns have the potential to affect an individual's quality of life. Excessive sweating can cause social embarrassment, while insufficient sweating can result in heat intolerance and dry skin. Depending on the severity of dyshidrosis, it may result in hyperkeratosis, rhagades, ulcerations, and poor wound healing due to altered epidermal moisturization. Sudomotor dysfunction is one of the most common and earliest neurophysiological manifestations of small fiber neuropathies. In some cases, it may be the only detectable neurologic manifestation. The gold standard for diagnosis of small fiber neuropathies is Intraepidermal Nerve Fiber Density (IENFD) measured from punch skin biopsies, but this procedure is invasive and inappropriate for long term follow-up. Sudomotor testing can be a valuable diagnostic tool for the early detection of small fiber neuropathies.
Hemoglobin pathogens are disorders caused by inherited autosomal recessive genes or hemoglobin structures that have been altered and changed. Autosomal recessive inheritance means acquiring two changed genes from each parent. If both parents are carriers for the autosomal recessive gene, there is a 75% chance the child will be normal and a 25% chance of having and expressing the disorder. There are various autosomal recessive disorders and hemoglobin pathogens, among these, beta-thalassemia is associated with changes in HbA2 levels in our blood. Thalassemia is a disorder involving both alpha and beta globin chains, is characterized by a deficiency in the globin chains within the hemoglobin, not characterized by the structural change to these chains. This deficiency leads to two disorders: beta-thalassemia and alpha-thalassemia. Beta-thalassemia has beta globin chains that are reduced and alpha-thalassemia has alpha globin chains that are also reduced. This disorder is the most common autosomal recessive disorder in some countries. Hemoglobin A2 is employed to diagnose thalassemia disorders, encompassing both beta and alpha types. In beta-thalassemia, affected individuals express elevated HbA2 levels, which can be a potential indicator of the heterozygous gene marker for the disorder. Normal levels range from 2.1-3.2%, but in the beta-thalassemia disorder, the levels increase to 3.5-6.0%. Additionally, individuals with beta-thalassemia exhibit a high red cell count and low hemoglobin levels.
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 registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.