Everything below concerns 肽纯度. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-02-23. Where a claim depends on a specific study, the study is described rather than over-claimed.
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
Lyophilized material is chemically stable for extended periods when kept dry, cold, and protected from light. The powder is hygroscopic, so vials should be warmed to room temperature before opening to reduce condensation on the contents. Once dissolved, the peptide is far less stable because peptide bonds are susceptible to hydrolysis and the methionine residue can oxidize. Solutions are typically aliquoted and held at 2-8 °C for short intervals or frozen for longer ones, and repeated freeze-thaw cycles should be avoided.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
| Property | Value | Notes |
|---|---|---|
| 结构类别 | 线性合成七肽 | 无环化结构，不含二硫键 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | N 端为甲硫氨酸 |
| 分子量 | 约 814 Da | 游离碱形式的计算值 |
| 外观 | 白色至类白色粉末 | 具吸湿性 |
| 溶解性 | 易溶于水 | 亦可溶于甲醇等极性溶剂 |
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its design combines the ACTH(4-7) core fragment with a C-terminal Pro-Gly-Pro extension, a modification intended to improve stability and prolong activity. The molecule is hydrophilic, carries no lipid chains or glycosylation, and has a theoretical mass just over 810 daltons in its free form. All seven residues are proteinogenic amino acids, so no non-natural building blocks appear in the backbone. A free N-terminal methionine and C-terminal proline define the unmodified parent peptide.
The compound was developed during the 1980s at the Institute of Molecular Genetics in Moscow as part of research on fragments of adrenocorticotropic hormone. Early work examined short ACTH-derived sequences that retained neurotrophic effects while lacking the endocrine activity of the full hormone. Semax entered clinical use in Russia during the 1990s, where it received registration for several neurological indications. Outside that region it remained primarily a laboratory research material rather than an approved therapeutic. English-language literature on it grew more slowly and frequently cited the original Russian studies.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It was derived from the ACTH(4-10) fragment, a short segment of adrenocorticotropic hormone that lacks the hormonal activity associated with the full-length peptide. Researchers at the Institute of Molecular Genetics in Moscow developed the compound during the 1980s. It has been registered as a pharmaceutical product in Russia and several neighbouring countries, where it is supplied as a nasal solution, and it is also sold internationally as a research chemical.
The proposed mechanism centres on neurotrophic signalling rather than direct receptor activation. Semax is reported to increase expression of brain-derived neurotrophic factor and nerve growth factor in several brain regions, and to shift the balance between excitatory and inhibitory neurotransmitter systems. Interaction with melanocortin receptors has been suggested because of the parent ACTH fragment. Many of these findings come from rodent studies, and the extent to which they translate to human physiology remains an open question.
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。
=== Built under license === Focke-Wulf C.19 – license-built (autogyro)– licence-built version of the Cierva C.19, with Siemens Sh 14 engine. (one prototype, converted from Cierva C.19 Mk.IV) Focke-Wulf C.30 Heuschrecke (Grasshopper) – licence-built version of the Cierva C.30, with Siemens Sh 14 engine. Focke-Wulf FWP.149D – license-built Piaggio P.149
=== Contaminant removal === Graphene oxide is non-toxic and biodegradable. Its surface is covered with epoxy, hydroxyl, and carboxyl groups that interact with cations and anions. It is soluble in water and forms stable colloid suspensions in other liquids because it is amphiphilic (able to mix with water or oil). Dispersed in liquids it shows excellent sorption capacities. It can remove copper, cobalt, cadmium, arsenate, and organic solvents.
=== Canonical signaling: The SMAD pathway === Smads are a class of intracellular signalling proteins and transcription factors for the TGF-β family of signalling molecules. This pathway conceptually resembles the Jak-STAT signal transduction pathway characterized in the activation of cytokine receptors implicated, for example, in the B cell isotype switching pathway. As previously stated, the binding of the TGF-β ligand to the TGF-β receptor, the type 2 receptor kinase phosphorylates and activates the type 1 receptor kinase that activates a signaling cascade. In the case of Smad, receptor-activated Smads are phosphorylated by the type 1 TGF-β receptor kinase, and these go on to complex with other Smads, which is able to translocate into the cell nucleus to induce transcription of different effectors. More specifically, activated TGF-β complexes bind to the type 2 domain of the TGF-β receptor which then recruits and phosphorylates a type 1 receptor. The type 1 receptor then recruits and phosphorylates a receptor regulated SMAD (R-SMAD). The R-SMAD then binds to the common SMAD (coSMAD) SMAD4 and forms a heterodimeric complex. This complex then enters the cell nucleus where it acts as a transcription factor for various genes, including those to activate the mitogen-activated protein kinase 8 pathway, which triggers apoptosis. The SMAD pathway is regulated by feedback inhibition. SMAD6 and SMAD7 may block type I receptors.
Sources: en.wikipedia.org
Pudzianowski faced boxer-turned-mixed martial artist Artur Szpilka at XTB KSW 83: Colosseum 2 on 3 June 2023. He lost the bout via technical knockout in the second round. Pudzianowski returned from an almost two year layoff to face another former World's Strongest Man, Eddie Hall, at KSW 105, on 26 April 2025. The bout was contested at Super Heavyweight, with two four-minute rounds. Pudzianowski was finished in the first round, being hurt by a right hand from Hall almost immediately, before succumbing to ground and pound 30 seconds in.
=== Energy conversion === Photocatalytic water splitting is an artificial photosynthesis process in which water is dissociated into hydrogen (H2) and oxygen (O2), using artificial or natural light. Methods such as photocatalytic water splitting are currently being investigated to produce hydrogen as a clean source of energy. The superior electron mobility and high surface area of graphene oxide sheets suggest it may be implemented as a catalyst that meets the requirements for this process. Specifically, graphene oxide's compositional functional groups of epoxide (-O-) and hydroxide (-OH) allow for more flexible control in the water splitting process. This flexibility can be used to tailor the band gap and band positions that are targeted in photocatalytic water splitting. Recent research experiments have demonstrated that the photocatalytic activity of graphene oxide containing a band gap within the required limits has produced effective splitting results, particularly when used with 40-50% coverage at a 2:1 hydroxide:epoxide ratio. When used in composite materials with CdS (a typical catalyst used in photocatalytic water splitting), graphene oxide nanocomposites have been shown to exhibit increased hydrogen production and quantum efficiency.
=== Nomenclatures === The dextrorotary (+)- or d- enantiomer is (1S,2S)-pseudoephedrine, whereas the levorotatory (−)- or l- form is (1R,2R)-pseudoephedrine. In the outdated d-/l- system, (+)-pseudoephedrine is also referred to as l-pseudoephedrine and (−)-pseudoephedrine as d-pseudoephedrine (in the Fischer projection, the phenyl ring is drawn at the bottom). Often the d-/l- system (with small caps) and the d-/l- system (with lower-case) are confused. The result is that the dextrorotatory d-pseudoephedrine is wrongly named d-pseudoephedrine and the levorotatory l-pseudoephedrine (the diastereomer) wrongly l-pseudoephedrine. The IUPAC names of the two enantiomers are (1S,2S)- and (1R,2R)- 2-methylamino-1-phenylpropan-1-ol, for the dextrorotatory and levorotatory enantiomers respectively. Synonyms for both are psi-ephedrine and threo-ephedrine. Pseudoephedrine is the INNTooltip International Nonproprietary Name of the (+)-/dextrorotatory form, when used as a pharmaceutical substance.
Sources: en.wikipedia.org
==== Specialized substitution matrices and their extensions ==== The real substitution rates in a protein depends not only on the identity of the amino acid, but also on the specific structural or sequence context it is in. Many specialized matrices have been developed for these contexts, such as in transmembrane alpha helices, for combinations of secondary structure states and solvent accessibility states, or for local sequence-structure contexts. These context-specific substitution matrices lead to generally improved alignment quality at some cost of speed but are not yet widely used. Since the 2000s, an increasing amount of matrices are defined for subsets of proteins not optimally aligned by traditional "general-purpose" matrices. These include:
== Manufacturing == Erythritol can be produced by enzymatic hydrolysis of the starch from corn to generate glucose. Glucose is then fermented with yeast or another fungus to produce erythritol. Because production through chemical synthesis is commercially not profitable, industrial production is biotechnologically done by fermentation of sugar with a genetically engineered strain of the yeast Yarrowia lipolytica. Alternatively, glycerol may be used as a carbon source and high osmotic pressure to increase yields up to 62%.
In response, the corporation aggressively executed a $200 million structural cost take-out program to mitigate rising supply chain costs and volatile tariff headwinds. Despite these efforts, annual net sales for fiscal 2025 fell to $15.52 billion, down from $16.60 billion in 2024. To stimulate demand, the company launched its largest pipeline of new product refreshes in over a decade, introducing more than 100 new appliances globally across its core brands, including KitchenAid, JennAir, and Maytag. In February 2026, Whirlpool announced a strategic recapitalization plan, launching concurrent public offerings of common stock and depositary shares totaling approximately $800 million. The net proceeds were aimed at deleveraging its balance sheet by paying down outstanding balances under its revolving credit facility and accelerating strategic investments in manufacturing automation. However, the company faced severe financial pressure in early 2026 due to rapid macroeconomic deterioration, shifting tariff landscapes, and high inventory reduction costs. In May 2026, Whirlpool reported a first-quarter GAAP net loss of $85 million, a steep reversal from the prior year's net earnings. To combat multi-year inflationary cost pressures, management announced a 10% domestic price increase in April 2026—its largest pricing action in a decade—with an additional 4% hike scheduled for July 2026.
Sources: en.wikipedia.org
不存在。它是依据 ACTH 的一段序列人工设计的分子，天然蛋白质中找不到与之完全相同的七肽。名称属于研究代号，而非天然物质名。
Semax 对应 ACTH 第 4 至第 10 位的片段，并在两端做了替换与延长，使其不再具备促肾上腺皮质激素的典型内分泌活性。这一改动同时改变了它在体内的稳定性与分布特征。
俄罗斯将其列为处方药物，需要医生开具处方。多数其他国家把它当作研究化合物，不能作为药品销售或宣称疗效。具体合法性取决于当地法规。
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.