Everything below concerns RP-HPLC. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-13. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility class | Freely soluble in water | Also dissolves in aqueous buffers |
| Typical storage temperature | -20 °C | Dry, desiccated, protected from light |
| Typical analytical method | RP-HPLC with UV detection | Often paired with LC-MS |
| Water content | Reported as Karl Fischer value | Freeze-dried material is hygroscopic |
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.
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。
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。
Transition options for transgender adolescents and youth are significantly limited compared to those for transgender adults. Prepubescent transgender youth can go through various social changes, such as presenting as their gender and asking to be called by a different name or different pronouns. Medical options for transition become available once the child begins to enter puberty. Under close supervision by a team of doctors, puberty blockers may be used to limit the effects of puberty. Discrimination has a significant effect on the mental health of young transgender people. The lack of family acceptance, rejection in schools and abuse from peers can be powerful stressors, leading to poor mental health and substance abuse. A study done on transgender youth in San Francisco found that higher rates of both transgender-based and racial bias are associated with increased rates of depression, post-traumatic stress disorder, and suicidal ideation. The Swiss National Advisory Commission on Biomedical Ethics (NCE) has suggested that research into treatments for gender-incongruent and gender-diverse young people should routinely consider the impact of social factors, including discrimination and social support, when analyzing their results. In a 2018 review, evidence suggested that hormonal treatments for transgender adolescents can achieve their intended physical effects.
== Cause == CJD is a type of transmissible spongiform encephalopathy (TSE), which is caused by prions. Prions are misfolded proteins that occur in the neurons of the central nervous system (CNS). The CJD prion is dangerous because it promotes refolding of cellular prion proteins into the diseased state. The number of misfolded protein molecules will increase exponentially, and the process leads to a large quantity of insoluble proteins in affected cells. This mass of misfolded proteins disrupts neuronal cell function and causes cell death. Mutations in the gene for the prion protein can cause a misfolding of the dominantly alpha helical regions into beta pleated sheets. This change in conformation disables the protein's ability to undergo digestion. Once the prion is transmitted, the defective proteins invade the brain and induce other prion protein molecules to misfold in a self-sustaining feedback loop. These neurodegenerative diseases are commonly called prion diseases. PrPC, the normal fibril cellular proteins responsible for a wide range of CNS functions, are misfolded by what current research suggests are small, highly neurotoxic oligomeric aggregates, known as PrPSc, which interact with cell surfaces to disrupt neuronal function. The binding of prion oligomers to normal prion protein on neurons may trigger toxic signals similar to how oligomeric β-amyloid causes synaptic damage in Alzheimer's disease.
== Background == Peptides can serve as sturdy building blocks for a wide range of materials as they can be designed to combine with a range of other building blocks such as lipids, sugars, nucleic acids, metallic nanocrystals, and so on; this gives the peptides an edge over carbon nanotubes, which are another popular nanomaterial, as the carbon structure is unreactive. They also exhibit biocompatibility and molecular recognition; the latter is particularly useful as it enables specific selectivity for building ordered nanostructures. Additionally, peptides have superb resistance to extreme temperature, detergents, and denaturants. The ability of peptides to perform self-assembly allows them to be used as fabrication tools, which will continue to grow as a fundamental part of nanomaterials production. The self-assembling of peptides is facilitated through the molecules' structural and chemical compatibility with each other. The structures formed demonstrate physical and chemical stability. An advantage to using self-assembling peptides to build nanostructures in a bottom-up approach is that specific features can be incorporated; the peptides can be modified to serve specific functions. This approach means the final structures are made from the self-integration of small, simple building blocks. This approach is needed for nanoscale structure, as the top-down method of miniaturizing devices using sophisticated lithography and etching techniques has reached a physical limit.
Sources: en.wikipedia.org
Singapore's stated foreign policy priority is maintaining security in Southeast Asia and surrounding territories. An underlying principle is political and economic stability in the region. It has diplomatic relations with more than 180 sovereign states. As one of the five founding members of ASEAN, Singapore is a strong supporter of the ASEAN Free Trade Area (AFTA) and the ASEAN Investment Area (AIA); it is also the host of the APEC Secretariat. Singapore is also a founding member of The Forum of Small States (FOSS), a voluntary and informal grouping at the UN. Singapore maintains membership in other regional organisations, such as Asia–Europe Meeting, the Forum for East Asia-Latin American Cooperation, the Indian Ocean Rim Association, and the East Asia Summit. It is also a member of the Non-Aligned Movement, the United Nations and the Commonwealth. While Singapore is not a formal member of the G20, it has been invited to participate in G20 processes in most years since 2010. Singapore is also the location of the Pacific Economic Cooperation Council (PECC) Secretariat. In general, bilateral relations with other ASEAN members are strong; however, disagreements have arisen, and relations with neighbouring Malaysia and Indonesia have sometimes been strained. Malaysia and Singapore have clashed over the delivery of fresh water to Singapore, and access by the Singapore Armed Forces to Malaysian airspace. Border issues exist with Malaysia and Indonesia, and both have banned the sale of marine sand to Singapore over disputes about Singapore's land reclamation.
Zebrafish Amphipod Hyalella curvispina, the earthworm Eisenia Andrei Tilapia Oreochromis mossambicus Frog Pseudacris regilla and salamander Ambystoma gracile Toad Rhinella arenarum Rainbow trout oncorhynchus mykiss Comparison between the toad Rhinella arenarum and the rainbow trout oncorhynchus mykiss Comparison between fish Mysidopsis bahia and Cyprinodon variegatus
Opponents of seed oils have argued that linoleic acid, an essential fatty acid found in seed oils such as safflower oil and sunflower oil increases chronic disease risk such as cardiovascular disease, cancer and systemic inflammation. This idea is not supported by data from recent clinical trials or long-term epidemiological studies. It has been shown that higher in vivo circulating and tissue levels of linoleic acid are associated with lower risk of major cardiovascular events. A 2025 review of human outcome data concluded that linoleic acid from seed oils does not increase chronic disease risk. The review also noted that the human research evidence shows that linoleic acid intake does not affect inflammation or increase inflammatory biomarkers. The World Cancer Research Fund and Cancer Council Australia have stated that there is no scientific evidence that consuming seed oils increases cancer risk.
Seven genes encode seven distinct 14-3-3 proteins in most mammals (See Human genes below) and 13–15 genes in many higher plants, though typically in fungi they are present only in pairs. Protists have at least one. Eukaryotes can tolerate the loss of a single 14-3-3 gene if multiple genes are expressed, but deletion of all 14-3-3s (as experimentally determined in yeast) results in death. 14-3-3 proteins are structurally similar to the Tetratrico Peptide Repeat (TPR) superfamily, which generally have 9 or 10 alpha helices, and usually form homo- and/or hetero-dimer interactions along their amino-termini helices. These proteins contain a number of known common modification domains, including regions for divalent cation interaction, phosphorylation & acetylation, and proteolytic cleavage, among others established and predicted. 14-3-3 binds to peptides. There are common recognition motifs for 14-3-3 proteins that contain a phosphorylated serine or threonine residue, although binding to non-phosphorylated ligands has also been reported. This interaction occurs along a so-called binding groove or cleft that is amphipathic in nature. To date, the crystal structures of six classes of these proteins have been resolved and deposited in the public domain.
Sources: en.wikipedia.org
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.
Dry lyophilised powder is generally kept at minus twenty degrees Celsius, protected from light and moisture. Repeated freeze-thaw cycles are avoided because they encourage aggregation and moisture uptake. Solutions are less stable than the solid form and degrade faster at room temperature.
A certificate documents what the supplier measured, not what an independent party confirmed. Methods, instruments and acceptance criteria can differ between suppliers. Third-party testing is the usual way to resolve discrepancies.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.