A practical reference on mass spectrometry: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
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 |
|---|---|---|
| Solid storage temperature | -20 °C or below | Desiccated and protected from light |
| Solution storage temperature | -80 °C as single-use aliquots | Avoid repeated freeze-thaw cycles |
| Purity assessment method | RP-HPLC, around 214 nm | Reported as main-peak area percent |
| Identity confirmation method | ESI-MS or MALDI-TOF | Measured mass compared with calculated mass |
| Common synonyms | ACTH(4-10) analog; Met-Glu-His-Phe-Pro-Gly-Pro | Also written as Semaxum in some sources |
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.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
Clinical reports describe use in ischaemic stroke, transient ischaemic attack, optic nerve conditions, and cognitive complaints, but most of these studies are small and were conducted in a single region. Systematic reviews have generally described the evidence base as limited in size and variable in methodological quality. Randomised controlled data suitable for international regulatory assessment are scarce. As a result, major treatment guidelines outside Russia do not include the peptide, and interest in it remains largely research-driven rather than routine clinical.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
== Controversies and criticism == In 2006, when he was a professor at the MIT Media Lab, Ariely conducted experiments including administering electric shocks with a research assistant who had no human-subject training. As a consequence, MIT's ethics committee banned Ariely from supervising data collection for a year. Ariely confirmed this and said that he was not aware that the research assistant did not have the needed one-hour online human-subject training. In 2021, a 2012 paper written by Francesca Gino, Max H. Bazerman, Nina Mazar, Lisa L Shu, and Ariely was discovered to be based on falsified data and was subsequently retracted. In 2024, Ariely told Business Insider that Duke had completed a three-year investigation that, according to him, concluded that data from the paper had been falsified but found no evidence that Ariely had used fake data knowingly. Duke University declined to comment on the grounds that their procedure is not to comment. In a 2024 LinkedIn article posted to his account, Ariely argued that he was able to replicate the findings in two papers he co-authored. In July 2021, the journal Psychological Science challenged a 2004 paper by James Heyman and Ariely, "prompted by some uncertainty regarding the values of statistical tests reported in the article and the analytic approach taken to the data". The authors were unable to resolve the ambiguities, because the original participant-level data was no longer available.
In 1965, Chinese scientists first synthesized crystalline bovine insulin (Chinese: 人工合成结晶牛胰岛素), which was the first functional crystalline protein being fully synthesized in the world. Research on synthesizing bovine insulin started on 1958. Members in the research group were from the Chemistry Department of Beijing University (Chinese: 北京大学化学系), Shanghai Institute of Biochemistry, CAS (Chinese: 中科院上海生物化学研究所) and Shanghai Institute of Organic Chemistry, CAS (Chinese: 中科院上海有机化学研究所). Insulin is a protein (peptide) consisting of two chain, A and B. Chain A consists of 21 amino acid residues while chain consists of 30 amino acid residues. The main function of insulin is to regulate the concentrate of sugar in blood. Type 1 diabetes are caused by dysfunction on the synthesis or secretory of insulin while injecting insulin can treat type 1 diabetes. In 1979, Wang Yinglai, the project's lead scientist, nominated Niu Jingyi, a team member who had made significant contributions, for the Nobel Chemistry Prize, but the nomination was unsuccessful.
=== Peripheral === Thyroxine is believed to be a prohormone and a reservoir for the most active and main thyroid hormone, T3. T4 is converted as required in the tissues by iodothyronine deiodinase. Deficiency of deiodinase can mimic hypothyroidism due to iodine deficiency. T3 is more active than T4, though it is present in less quantity than T4.
Sources: en.wikipedia.org
Diamondback moths cause US$4 to $5 billion of damage each year worldwide. The approach is similar to the sterile technique tested on mosquitoes, where males are transformed with a gene that prevents any females born from reaching maturity. They underwent field trials in 2017. Genetically modified moths have previously been released in field trials. In this case a strain of pink bollworm that were sterilized with radiation were genetically engineered to express a red fluorescent protein making it easier for researchers to monitor them. Silkworm, the larvae stage of Bombyx mori, is an economically important insect in sericulture. Scientists are developing strategies to enhance silk quality and quantity. There is also potential to use the silk producing machinery to make other valuable proteins. Proteins currently developed to be expressed by silkworms include; human serum albumin, human collagen α-chain, mouse monoclonal antibody and N-glycanase. Silkworms have been created that produce spider silk, a stronger but extremely difficult to harvest silk, and even novel silks.
This concept of feed-forward stimulation will likely become more prevalent as physiological markers of targeted diseases and neural disorders are discovered and verified. The on-demand stimulation may may extend the duration of battery life if sensing and signal-processing demands of the system are sufficiently power-efficient. New electrode designs could yield more efficient and precise stimulation, requiring less current and minimizing unwanted side-stimulation. In addition, to overcome the challenge of preventing lead migration in areas of the body that are subject to motion such as turning and bending, researchers are exploring developing small stimulation systems that are recharged wirelessly rather than through an electrical lead.
=== Haemophilus influenzae type b (Hib) infection === Naturally acquired disease caused by H. influenzae seems to occur in humans only. In healthy children under the age of 5, H. influenzae type b was responsible for more than 80% of aggressive infections, before the introduction of the [Hib] vaccine. In infants and young children, H. influenzae type b (Hib) causes bacteremia, pneumonia, epiglottitis and acute bacterial meningitis. On occasion, it causes cellulitis, osteomyelitis, and infectious arthritis. It is one cause of neonatal infection. Due to routine use of the Hib vaccine in the US since 1990, the incidence of invasive Hib disease has decreased to 1.3/100,000 in children. However, Hib remains a major cause of lower respiratory tract infections in infants and children in developing countries where the vaccine is not widely used. Unencapsulated H. influenzae strains are unaffected by the Hib vaccine and cause ear infections (otitis media), eye infections (conjunctivitis), and sinusitis in children, and are associated with pneumonia.
== Epidemiology == Hypermobility occurs in about 10 to 25% of the population. It is reported more often in females than males. Hypermobile joints are also relatively common among children, though this is often benign.
Sources: en.wikipedia.org
Each freeze-thaw cycle can degrade a fraction of the peptide and promote aggregation. Dividing a stock solution into single-use volumes removes repeated cycling as a variable. It also limits the time a thawed solution spends at room temperature.
A high main-peak percentage says little about identity, counter-ion content, or residual solvents. It also does not distinguish an isomer or a closely eluting analog. Mass confirmation and the accompanying documentation cover those gaps.
Salt form changes mass, solubility, and hygroscopicity, and acetate and trifluoroacetate salts behave differently in solution. Storage guidance still centers on -20 °C for powder and lower temperatures for solutions. The certificate should state which salt is present.
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。