If you have been reading about Pro-Gly-Pro tail 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 2026-06-14. Numbers and descriptions here follow the published literature rather than marketing material.
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。
Purity assessment relies mainly on reversed-phase high-performance liquid chromatography, which separates the target heptapeptide from truncated sequences, deletion analogues, and oxidised forms. Mass spectrometry, usually coupled to liquid chromatography, confirms identity through the expected molecular ion and reveals modifications such as methionine sulfoxide formation. Amino acid analysis can verify composition, and tandem mass spectrometry supports sequence confirmation. Ultraviolet detection near 254 to 280 nanometres is convenient because the phenylalanine and histidine residues absorb in that region. Nuclear magnetic resonance is rarely used for routine release testing.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
Solid semax is typically supplied as a lyophilised powder that is hygroscopic and sensitive to moisture, light, and repeated temperature cycling. Long-term storage of the dry peptide is generally recommended at approximately -20 degrees Celsius, while shorter working periods may use refrigeration at 2 to 8 degrees Celsius. Vials should remain tightly closed and desiccated when brought to room temperature, because condensation can damage the material before it is weighed. Dividing a batch into aliquots is preferable to thawing one container repeatedly.
| Property | Value | Notes |
|---|---|---|
| 化学类别 | 合成七肽 | ACTH(4-10) 结构类似物 |
| 氨基酸序列 | Met-Glu-His-Phe-Pro-Gly-Pro | 单字母写作 MEHFPGP |
| 分子量 | 约 813.9 Da | 随确切形式和盐型略有变化 |
| 常见同义词 | ACTH(4-10) 类似物 | 俄语文献称 Семакс |
| 开发来源 | 俄罗斯 | 二十世纪八十年代 |
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. It was developed as a fragment analog of adrenocorticotropic hormone, modeled specifically on the ACTH(4-10) region. The first four residues reproduce that fragment, while a Pro-Gly-Pro tripeptide is appended at the C-terminus. Work on the compound originated in Russia, where it entered clinical use as an intranasal preparation. Its sequence places it among short regulatory peptides studied for effects on the central nervous system rather than on the adrenal axis.
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
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.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
The cell's energy is equal to the voltage times the charge. Each gram of lithium represents Faraday's constant / 6.941(atomic mass), or 13,901 coulombs. At 3 V, this gives 41.7 kJ per gram of lithium, or 11.6 kWh per kilogram of lithium. This is slightly more than the heat of combustion of gasoline; however, lithium-ion batteries as a whole are still significantly heavier per unit of energy due to the additional materials used in production. Note that the cell voltages involved in these reactions are larger than the potential at which an aqueous solutions would electrolyze.
gives excellent agreement of Griffith's predicted fracture stress with experimental results for glass. For the simple case of a thin rectangular plate with a crack perpendicular to the load, the energy release rate,
The 5 body regions are right upper, left upper, right lower, left lower, and axial. The Widespread Pain Index (WPI) was introduced by the American College of Rheumatology in 2010. It measures the number of body regions experiencing pain, out of a total of 19: left and right shoulder girdle, upper arm, lower arm, hip/buttock/trochanter, upper leg, lower leg, and jaw; plus the chest, abdomen, neck, upper back and lower back. The Symptom Severity Scale (SSS) assesses the severity of six symptoms; fatigue (score 0-3, for no problem, mild, moderate and severe), trouble thinking or remembering (0-3), waking up tired (unrefreshed) (0-3), pain or cramps in lower abdomen (0-1), depression (0-1) and headache (0-1). As of 2022, among diagnosis methods in the US, the ACR 2016 criteria have been judged as the best FM diagnosis criteria available. The UK RCP also recommends these criteria for FM diagnosis. A similar diagnostic approach is taken in Germany.In 2019, the American Pain Society in collaboration with the U.S. Food and Drug Administration developed a new diagnostic system using two dimensions. The first dimension included core diagnostic criteria, and the second included common features. The core diagnostic criteria are:
Sources: en.wikipedia.org
=== Adulthood === Human vocal cords are paired structures located in the larynx, just above the trachea, which vibrate and are brought in contact during phonation. The human vocal cords are roughly 12–24 mm in length, and 3–5 mm thick. Histologically, the human vocal cords are a laminated structure composed of five different layers. The vocalis muscle, main body of the vocal cords, is covered by the mucosa, which consists of the epithelium and the lamina propria. The latter is a pliable layer of connective tissue subdivided into three layers: the superficial layer (SL), the intermediate layer (IL), and the deep layer (DL). Layer distinction is either made looking at differential in cell content or extracellular matrix (extracellular matrix) content. The most common way being to look at the extracellular matrix content. The SLP has fewer elastic and collagenous fibers than the two other layers, and thus is looser and more pliable. The ILP is mostly composed of elastic fibers, while the DLP has fewer elastic fibers, and more collagenous fibers. In those two layers, which form what is known as the vocalis ligament, the elastic and collagenous fibers are densely packed as bundles that run almost parallel to the edge of the vocal fold. There is a steady increase in the elastin content of the lamina propria as humans age (elastin is a yellow scleroprotein, the essential constituent of the elastic connective tissue) resulting in a decrease in the ability of the lamina propria to expand caused by cross-branching of the elastin fibers.
== Management of ships == Fleet management also refers to the management of ships while at sea. Shipping fleet management contracts are normally given to fleet management companies that handle aspects like crewing, maintenance, and day-to-day operations. This gives the ship owner time to concentrate on cargo booking.
[C]hildren are used in many parts of the world as an illicit drug consumers market and for purposes of illicit production, distribution and trade in narcotic drugs and psychotropic substances, which entails a danger of incalculable gravity.
Sources: en.wikipedia.org
== Using data obtained to find concentration of unknown == In summary, in order to find a standard curve, one must use varying concentrations of BSA (Bovine Serum Albumin) in order to create a standard curve with concentration plotted on the x-axis and absorbance plotted on the y-axis. Only a narrow concentration of BSA is used (2-10 ug/mL) in order to create an accurate standard curve. Using a broad range of protein concentration will make it harder to determine the concentration of the unknown protein. This standard curve is then used to determine the concentration of the unknown protein. The following elaborates on how one goes from the standard curve to the concentration of the unknown. First, add a line of best fit, or Linear regression and display the equation on the chart. Ideally, the R2 value will be as close to 1 as possible. R represents the sum of the square values of the fit subtracted from each data point. Therefore, if R2 is much less than one, consider redoing the experiment to get one with more reliable data.
The four hereditary types of VWD described are type 1, type 2, type 3, and pseudo- or platelet-type. Most cases are hereditary, but acquired forms of VWD have been described. The International Society on Thrombosis and Haemostasis's classification depends on the definition of qualitative and quantitative defects.
== Further reading == Inglis, Julia J.; Criado, Gabriel; Medghalchi, Mino; Andrews, Melanie; Sandison, Ann; Feldmann, Marc; Williams, Richard O. (29 October 2007). "Collagen-induced arthritis in C57BL/6 mice is associated with a robust and sustained T-cell response to type II collagen". Arthritis Research & Therapy. 9 (5): R113. doi:10.1186/ar2319. ISSN 1478-6354. PMC 2212575. PMID 17967186. Pietrosimone, K. M.; Jin, M.; Poston, B.; Liu, P. (20 October 2015). "Collagen-Induced Arthritis: A model for Murine Autoimmune Arthritis". Bio-Protocol. 5 (20) e1626. doi:10.21769/bioprotoc.1626. ISSN 2331-8325. PMC 4629450. PMID 26539560. Holmdahl, Rikard; Bockermann, Robert; Bäcklund, Johan; Yamada, Hisakata (1 February 2002). "The molecular pathogenesis of collagen-induced arthritis in mice—a model for rheumatoid arthritis". Ageing Research Reviews. 1 (1): 135–147. doi:10.1016/S0047-6374(01)00371-2. ISSN 1568-1637. PMID 12039453. S2CID 28243127.
== External links == Collagen+type+III at the U.S. National Library of Medicine Medical Subject Headings (MeSH) "COL3A1". Ehlers Danlos Syndrome Variant Database. Archived from the original on 2021-01-26. Retrieved 2018-12-05. "Report for CCDS2297.1". Consensus Coding Sequence (CDS) Database. National Center for Biotechnology Information (NCBI).
Sources: en.wikipedia.org
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。
Semax 被描述为 ACTH(4-10) 的结构类似物，两者共享部分序列特征。它保留了该片段的部分神经相关活性方向，但去除了完整片段带来的激素释放效应。二者并非同一物质，也不能互相替代。
加入的 Pro-Gly-Pro 三肽被普遍认为能提升分子对蛋白水解酶的稳定性。这种设计让短肽在体内维持时间更长。具体延长的程度以及不同组织中是否一致，文献中仍存在不同报告。
Dry powder is usually kept at about -20 degrees Celsius for long-term storage and at 2 to 8 degrees Celsius for short working periods. Containers should stay sealed and protected from light and moisture to limit degradation.