The short version of lyophilisation fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-24. Anything still debated is marked as such rather than presented as settled.
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。
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。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
| 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.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
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.
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.
type of shadowing (lines, dots or rings) reticular (crisscrossing lines) companion shadow (lines paralleling bony landmarks) nodular (many small dots) rings or cysts ground glass consolidation (diffuse opacity with air bronchograms) location (where is the lesion worst?) upper (e.g., sarcoid, tuberculosis, silicosis/pneumoconiosis, ankylosing spondylitis, Langerhans cell histiocytosis) lower (e.g., cryptogenic fibrosing alveolitis, connective tissue disease, asbestosis, drug reactions) central (e.g., pulmonary edema, alveolar proteinosis, lymphoma, Kaposi's sarcoma, PCP) peripheral (e.g., cryptogenic fibrosing alveolitis, connective tissue disease, chronic eosinophilic pneumonia, bronchiolitis obliterans organizing pneumonia) lung volume increased (e.g., Langerhans cell histiocytosis, lymphangioleiomyomatosis, cystic fibrosis, allergic bronchopulmonary aspergillosis) decreased (e.g., fibrotic lung disease, chronic sarcoidosis, chronic extrinsic allergic alveolitis) Pleural effusions may occur with cancer, sarcoid, connective tissue diseases and lymphangioleiomyomatosis. The presence of a pleural effusion argues against pneumocystis pneumonia.
Hans Wolfgang Schumann argues that a comparison of the twelve nidanas with the five skhandhas shows that the 12 link chain contains logical inconsistencies, which can be explained when the chain is considered to be a later elaboration. Schumann thus concluded that the twelvefold chain was a later synthesis composed by Buddhist monks, consisting of three shorter lists. These lists may have encompassed nidana 1–4, 5–8, and 8-12. Schumann also proposes that the 12 nidanas are extended over three existences, and illustrates the succession of rebirths. While Buddhaghosa and Vasubandhu maintain a 2-8-2 schema, Schumann maintains a 3-6-3 scheme. According to Richard Gombrich, the twelve-fold list is a combination of two previous lists, the second list beginning with tanha, "thirst", the cause of suffering as described in the second noble truth". The first list consists of the first four nidanas, which reference Vedic cosmogony, as described by Jurewicz. According to Gombrich, the two lists were combined, resulting in contradictions in its reverse version.
== Biology and Uses == Pisolithus arhizus is made up of networks of hyphae, the thin filamentous structures that compose the its mycelium. In Pisolithus fungi, spores are produced in basidia on the fungus's fruiting body. A recent study testing arhizus compounds looked into the cellular compounds and discovered twenty new "triterpenoid" compounds that had never before been documented, as well as assorted pigments and phenolic acids. As its chemical composure continues to be researched, studies have claimed significant medical potential for the Pisolithus group in general. A study on the broader genus revealed compounds with significant antibiotic properties and killed resistant strains of bacteria from real patients' wounds. Also, certain triterpenoids yielded impressive results in killing leukemia, melanoma, and brain cancer cells without harming healthy human blood cells they were with. A paper that hones in on Pisolithus arhizus specifically notes that arhizus had anti-genotoxic properties in addition to the antibacterial effects found from using methanol and ethanol extracts of the fungus (in comparison to the specific isolated compounds from the study mentioned before). The fungus also showed strong cytotoxicity (at high concentrations eliminated up to 97% cancer cells) against a colon cancer cell line. Although the study didn't give results of the testing on healthy human cells, it's findings are promising for future research.
Membrane interaction of alpha-synuclein modulates or affects its rate of aggregation. The membrane-mediated modulation of aggregation is very similar to that observed for other amyloid proteins such as IAPP and abeta. Aggregated states of alpha-synuclein permeate the membrane of lipid vesicles. They are formed upon interaction with peroxidation-prone polyunsaturated fatty acids (PUFA) but not with monounsaturated fatty acids and the binding of lipid autoxidation-promoting transition metals such as iron or copper provokes oligomerization of alpha-synuclein. The aggregated alpha-synuclein has a specific activity for peroxidized lipids and induces lipid autoxidation in PUFA-rich membranes of both neurons and astrocytes, decreasing resistance to apoptosis. Lipid autoxidation is inhibited if the cells are pre-incubated with isotope-reinforced PUFAs (D-PUFA).
Sources: en.wikipedia.org
== Medical uses == In the United States, sotagliflozin is indicated to reduce the risk of cardiovascular death, hospitalization for heart failure, and urgent heart failure visit in adults with heart failure; or type 2 diabetes, chronic kidney disease, and other cardiovascular risk factors.
Around 99.8% of genes that undergo mutations are deemed silent because the nucleotide change does not change the amino acid being translated. Although silent mutations are not supposed to have an effect on the phenotypic outcome, some mutations prove otherwise like the Multi-Drug Resistance Gene 1. MDR1 codes for the P-glycoprotein which helps get rid of drugs in the body. It is located in the intestines, liver, pancreas, and brain. MDR 1 is located in the same places that CYP3A4 is located in, which is an enzyme that helps get rid of toxins or drugs from the liver and intestines. Silent mutations like MDR 1 do express a change in phenotypic response. A study done on mice showed when they did not have enough of the MDR 1 gene, their body did not recognize the ivermectin or cyclosporine drug, leading to the creation of toxins in their bodies. MDR1 has over fifty single nucleotide polymorphisms (SNP's) which are changes in the nucleotide base sequence. In MDR1 the gene exon 26 which represents 3535C can mutate to 3535T which then changes the transfer RNA into one that is not often as seen, leading to changes in the outcome during translation. This is an example of how some silent mutations are not always silent. The multi-drug resistance genes at Exon 26 C3435T, exon 21 G2677T/A, and exon 12 C1236T have been studied to have SNP's that occur at the same time, therefore making the phenotypic "function "change. This suggests a haplotype dependency between exon 26 and other exon that have polymorphisms.
The specialised force of the CIF was raised by the Government following the worsening situation in the Jungle Mahals. The force was charged with the specific task of curbing presence of the maoists within the state. The force was allowed its own recruiting process so as to select the best men from within the force. The force is headed by an Additional Director General of Police ranked officer.
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。
不是。Semax 是完全人工合成的七肽，自然界中没有对应的已知肽段。它的设计灵感来自促肾上腺皮质激素片段 ACTH(4-10)，但序列经过了替换和延长。