semax raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-04-21 and is reviewed periodically as new material appears.
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.
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.
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular weight | ~813.9 Da (free heptapeptide) | N-acetylated form is about 42 Da heavier |
| Residue count | 7 (heptapeptide) | Four residues from ACTH(4-10), three added |
| Appearance | White to off-white powder | Usually supplied lyophilized |
| Solubility class | Freely soluble in water | Also dissolves in DMSO and polar organic solvents |
| Related parent fragment | ACTH(4-10) | Parent motif is Met-Glu-His-Phe |
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。
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
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.
Portal 2 development was restarted specifically to keep the portal concept but adding new elements to freshen the gameplay. During this period, Valve had witnessed another student project out of DigiPen, Tag: The Power of Paint, which allows the player to spray paint onto surfaces to alter their behavior. The team was brought into Valve, though not initially as part of the Portal franchise. The Tag team had found a way to incorporate their paints with real-time fluid dynamics code previously made by Valve, and the concept became the "conversion gels" found in Portal 2. Valve included a co-operative play mode, based on their own observations and stories from players about working out the solutions to Portal's puzzles in a group environment. With this feature, they sought the ability to enable cross-platform play of Portal 2 between computers and consoles through Steamworks. This led to a surprise reveal by Newell that Portal 2 would be released on the PlayStation 3, despite previously expressing how he felt about the difficulties in supporting the console, and that it would include support for cross-platform play between the PC and PS3 versions through a limited Steamworks interface. Valve brought in writer Jay Pinkerton, who had formerly worked on National Lampoon, as well as Left 4 Dead writer Chet Faliszek to assist Wolpaw with the larger story.
In his free time, Thomas visited the cinema in Uplands, took walks along Swansea Bay, and frequented Swansea's pubs, especially the Antelope and the Mermaid Hotels in Mumbles. In the Kardomah Café, close to the newspaper office in Castle Street, he met his creative contemporaries, including his friend the poet Vernon Watkins and the musician and composer, Daniel Jones with whom, as teenagers, Thomas had helped to set up the "Warmley Broadcasting Corporation". This group of writers, musicians and artists became known as "The Kardomah Gang". This was also the period of his friendship with Bert Trick, a local shopkeeper, left-wing political activist and would-be poet, and with the Rev. Leon Atkin, a Swansea minister, human rights activist and local politician. In 1933, Thomas visited London for probably the first time.
=== Radioiodine === In iodine-131 (radioiodine) radioisotope therapy, which was first pioneered by Dr. Saul Hertz, radioactive iodine-131 is given orally (either by pill or liquid) on a one-time basis, to severely restrict, or altogether destroy the function of a hyperactive thyroid gland. This isotope of radioactive iodine used for ablative treatment is more potent than diagnostic radioiodine (usually iodine-123 or a very low amount of iodine-131), which has a biological half-life of 8–13 hours. Iodine-131, which also emits beta particles that are far more damaging to tissues at short range, has a half-life of approximately 8 days. People not responding sufficiently to the first dose are sometimes given an additional radioiodine treatment at a larger dose. Iodine-131 in this treatment is picked up by the active cells in the thyroid and destroys them, rendering the thyroid gland mostly or completely inactive. Since iodine is picked up more readily (though not exclusively) by thyroid cells, and (more importantly) is picked up even more readily by overactive thyroid cells, the destruction is local, and there are no widespread side effects with this therapy. Radioiodine ablation has been used for over 50 years, and the only major reasons for not using it are pregnancy and breastfeeding (breast tissue also picks up and concentrates iodine). Once the thyroid function is reduced, replacement hormone therapy (levothyroxine) taken each day orally replaces the thyroid hormone that is normally produced by the body.
Tissues which take up stains are called chromatic. Chromosomes were so named because of their ability to absorb a violet stain. Positive affinity for a specific stain may be designated by the suffix -philic. For example, tissues that stain with an azure stain may be referred to as azurophilic. This may also be used for more generalized staining properties, such as acidophilic for tissues that stain by acidic stains (most notably eosin), basophilic when staining in basic dyes, and amphophilic when staining with either acid or basic dyes. In contrast, chromophobic tissues do not take up coloured dye readily.
== Pathophysiology == Myophosphorylase is involved in the breakdown of glycogen to glucose-1-phosphate for use in muscle. The enzyme removes 1,4 glycosyl residues from the outer branches of glycogen and adds inorganic phosphate to form glucose-1-phosphate. Ordinarily, the removal of 1,4 glycosyl residues by myophosphorylase leads to the formation of glucose-1-phosphate during glycogen breakdown and the polar, phosphorylated glucose cannot leave the cell membrane and so is marked for intracellular catabolism. In McArdle's disease, deficiency of myophosphorylase leads to the accumulation of intramuscular glycogen and a lack of glucose-1-phosphate for cellular fuel. Myophosphorylase comes in two forms: form 'a' is phosphorylated by phosphorylase kinase, form 'b' is not phosphorylated. Form 'a' is de-phosphorylated into form 'b' by the enzyme phosphoprotein phosphatase, which is activated by elevated insulin. Both forms have two conformational states: active (R or relaxed) and inactive (T or tense). When either form 'a' or 'b' is in the active state, then the enzyme converts glycogen into glucose-1-phosphate. Myophosphorylase-b is allosterically activated by elevated AMP within the cell, and allosterically inactivated by elevated ATP and/or glucose-6-phosphate. Myophosphorylase-a is active unless allosterically inactivated by elevated glucose within the cell. In this way, myophosphorylase-a is the more active of the two forms as it will continue to convert glycogen into glucose-1-phosphate even with high levels of glycogen-6-phosphate and ATP.
Sources: en.wikipedia.org
A cigarette filter or filter tip is a component of a cigarette. Filters are typically made from cellulose acetate fibre. Most factory-made cigarettes are equipped with a filter; those who roll their own can buy them separately. Filters can reduce the presence of some substances, such as tar, in cigarette smoke, but do not actually make them any safer to smoke.
Moreover, the nucleus of any atom that has a net nuclear spin and that is bonded to a hydrogen atom could potentially be imaged via heteronuclear magnetization transfer MRI that would image the high-gyromagnetic-ratio hydrogen nucleus instead of the low-gyromagnetic-ratio nucleus that is bonded to the hydrogen atom. In principle, heteronuclear magnetization transfer MRI could be used to detect the presence or absence of specific chemical bonds. Multinuclear imaging is primarily a research technique at present. However, potential applications include functional imaging and imaging of organs poorly seen on 1H MRI (e.g., lungs and bones) or as alternative contrast agents. Inhaled hyperpolarized 3He can be used to image the distribution of air spaces within the lungs. Injectable solutions containing 13C or stabilized bubbles of hyperpolarized 129Xe have been studied as contrast agents for angiography and perfusion imaging. 31P can potentially provide information on bone density and structure, as well as functional imaging of the brain. Multinuclear imaging holds the potential to chart the distribution of lithium in the human brain, this element finding use as an important drug for those with conditions such as bipolar disorder.
White Rhodesians mostly spoke English, with a minority that spoke Afrikaans. Approximately 70% of black Rhodesians spoke Shona, and around 20% spoke Ndebele. A majority of Rhodesia's Indian community spoke Gujarati and a minority spoke Hindi.
The reaction proceeds with an initial [4+1] cycloaddition followed by a reversion to eliminate a thermodynamic sink and prevent reversibility. This product is stable if a tertiary amine or isocyanopropanoate is used. If a secondary or primary isocyanide is used, the produce will form an imine which is quickly hydrolyzed. Isocyanide is a favored chemical reporter due to its small size, stability, non-toxicity, and absence in mammalian systems. However, the reaction is slow, with second order rate constants on the order of 10−2 M−1•s−1.
Sources: en.wikipedia.org
Developmental expression patterns of four chemosensory protein genes from the Eastern spruce budworm, Choristoneura fumiferana. Insect Mol Biol. 2005; 14: 289-300. 19. Ma C, Cui S, Tian Z, Zhang Y, Chen G, Gao X, Tian Z, Chen H, Guo J, Zhou Z. OcomCSP12, a chemosensory protein expressed specifically by ovary, mediates reproduction in Ophraella communa (Coleoptera: Chrysomelidae). Front Physiol. 2019; 10: 1290. 20. Picimbon JF, Dietrich K, Breer H, Krieger J. Chemosensory proteins of Locusta migratoria (Orthoptera : Acrididae). Insect Biochem Mol Biol. 2000a; 30: 233-241. 21. Guo W, Wang X, Ma Z, Xue L, Han J, Yu D, Kang L. CSP and Takeout genes modulate the switch between attraction and repulsion during behavioral phase change in the migratory locust. PLoS Genet. 2011; 7: e1001291. 22. Martín-Blázquez R, Chen B, Kang L, Bakkali M. Evolution, expression and association of the chemosensory protein genes with the outbreak phase of the two main pest locusts. Sci Rep. 2018; 7: 6653. 23. Zhu J, Iovinella I, Dani FR, Pelosi P, Wang G. Chemosensory proteins: A versatile binding family. In: Picimbon JF (Ed.), Olfactory Concepts of Insect Control-Alternative to Insecticides. vol. 2 Springer Nature, Switzerland, 2019, pp. 147–169. 24. Liu GX, Yue S, Rajashekar B, Picimbon JF. Expression of chemosensory protein (CSP) structures in Pediculus humanis corporis and Acinetobacter baumannii. SOJ Microbiol Infect Dis. 2019; 7: 1-17. 25. Liu GX, Ma HM, Xie HY, Xuan N, Picimbon JF.
water A polar inorganic compound with the chemical formula H2O that is a tasteless, odorless, and generally colorless liquid at standard temperature and pressure, though it also occurs naturally as a solid and a gas at the Earth's surface. It is the most abundant substance on Earth and therefore an integral component of virtually all chemical and biological systems. Water is often described as the "universal solvent" for its inherent ability to dissolve many substances.
== Connection to nitrogen storage in Cyanobacteria == Cyanophycin is highly resistant to degradation by all conventional proteases, and the only enzyme known to be capable of hydrolyzing it is cyanophycinase. Cyanophycin is a non-ribosomally synthesized peptidyl polymer that is used for nitrogen storage by cyanobacteria and other select eubacteria. Approximately 90% of cyanobacteria are diazotrophic, meaning that they can grow without an external source of fixed nitrogen. Diazotrophic growth was severely impaired in bacteria with a mutated cyanophycinase gene, indicating that the inability to degrade cyanophycin is detrimental for the diazotrophic growth of the cyanobacterium, due to an excess of nitrogen storage.
=== Considerations === Since Scoville ratings are defined per unit of dry mass, comparison of ratings between products having different water content can be misleading. For example, typical fresh chili peppers have a water content around 90%, whereas Tabasco sauce has a water content of 95%. For law-enforcement-grade pepper spray, values from 500,000 up to 5 million SHU have been reported, but the actual strength of the spray depends on the dilution. This problem can be overcome by stating the water content along with the Scoville value. One way to do so is the "D-value", defined as total mass divided by dry mass. Numerical results for any specimen vary depending on its cultivation conditions and the uncertainty of the laboratory methods used to assess the capsaicinoid content. Pungency values for any pepper are variable, owing to expected variation within a species, possibly by a factor of 10 or more, depending on seed lineage, climate and humidity, and soil composition supplying nutrients. The described inaccuracies in measurement methods contribute to the imprecision of measured values.
In regions where Druze and Christians coexist, such as parts of Lebanon, Syria and Israel, the veneration of Mary often reflects a blend of traditions. Shared pilgrimage sites and mutual respect for places like the Church of Saidet et Tallé in Deir el Qamar, the Our Lady of Lebanon shrine in Harrisa, the Our Lady of Saidnaya Monastery in Saidnaya, and the Stella Maris Monastery in Haifa exemplify this. Historical records and writings by authors like Pierre-Marie Martin and Glenn Bowman show that Druze leaders and community members have historically shown deep reverence for Marian sites. They often sought her intercession before battles or during times of need, demonstrating a cultural and spiritual integration of Marian veneration into their religious practices. In Lebanon, the Virgin Mary serves as a unifying figure among Druze, Muslims, and Christians, fostering a sense of shared heritage and mutual respect. Nour Fara Haddad, a scholar of religious anthropology, states that this unity is particularly important in maintaining the social and cultural bonds between these communities.
Sources: en.wikipedia.org
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.
Semax is a synthetic analog of the ACTH(4-10) fragment rather than a copy of the full hormone. Truncation plus the added tail removes the steroidogenic portion of ACTH. That distinction explains why it is studied for nervous-system effects instead of adrenal stimulation.
It is registered as a prescription product in Russia and has been used there clinically, chiefly by the intranasal route. No approval exists in the United States or the European Union. Availability elsewhere typically falls under research-chemical distribution, with varying purity documentation.
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.