The short version of neurotrophic factor fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-30. Anything still debated is marked as such rather than presented as settled.
Semax binds to melanocortin receptors and is thought to influence neuronal survival and plasticity rather than to act through the adrenal axis. Laboratory work has shown increased expression of brain-derived neurotrophic factor and nerve growth factor in treated tissue. Changes in c-Fos, a marker of neuronal activation, have also been reported. Because the peptide is rapidly degraded by peptidases, its effects are generally attributed to downstream signaling cascades rather than to sustained receptor occupancy.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
| Property | Value | Notes |
|---|---|---|
| Appearance | White lyophilized powder | Typical for synthetic peptides |
| Solubility | Freely soluble in water | Also soluble in saline |
| Storage temperature | -20 C or below | Protect from repeated freeze-thaw |
| Analytical method | Reverse-phase HPLC | Confirms purity and identity |
| Common synonym | ACTH(4-10) analog | Reflects structural origin |
从分子层面看，Semax 是线性七肽，没有二硫键、糖基或脂链修饰，N 端为游离氨基，C 端为游离羧基。分子含组氨酸与谷氨酸侧链，因此在水和甲醇等极性溶剂中溶解良好，在非极性溶剂中溶解有限。计算分子量约为 814 Da，与其质子化离子的质荷比吻合，可用于质谱确认。
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。
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.
Terminology around the compound varies by source. It appears in catalogues and papers as Semax, as the heptapeptide ACTH(4-7)-Pro-Gly-Pro, and under various alphanumeric laboratory codes used by individual suppliers. These names refer to the same sequence but may imply different salt forms, purity grades, or counter-ions. Peptide databases usually list the free base mass, while product descriptions sometimes report acetate or trifluoroacetate salts with a different formula weight. Because naming conventions for research peptides are not standardised across vendors, checking the declared sequence and measured mass is more reliable than relying on a trade name alone.
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.
== Chemistry == Many different geometric isomers of retinol, retinal and retinoic acid are possible as a result of either a trans or cis configuration of four of the five double bonds found in the polyene chain. The cis isomers are less stable and can readily convert to the all-trans configuration (as seen in the structure of all-trans-retinol shown at the top of this page). Nevertheless, some cis isomers are found naturally and carry out essential functions. For example, the 11-cis-retinal isomer is the chromophore of rhodopsin, the vertebrate photoreceptor molecule. Rhodopsin is composed of the 11-cis-retinal covalently linked via a Schiff base to the opsin protein (either rod opsin or blue, red, or green cone opsins). The process of vision relies on the light-induced isomerisation of the chromophore from 11-cis to all-trans resulting in a change of the conformation and activation of the photoreceptor molecule. Many of the non-visual functions of vitamin A are mediated by retinoic acid, which regulates gene expression by activating nuclear retinoic acid receptors. The non-visual functions of vitamin A are essential in the immunological function, reproduction, and embryonic development of vertebrates as evidenced by the impaired growth, susceptibility to infection, and birth defects observed in populations receiving suboptimal vitamin A in their diet.
== Sources == MCD peptide is a component of bumblebee (Megabombus pennsylvanicus) venom. In addition to MCD peptide, melittin and apamin have also been identified in this venom and are also described as voltage-dependent channel blockers. MCD peptide is also present in the venom of the honey bee Apis mellifera.
Big gastrin (G-34) is a form of gastrin with 34 amino acids in its sequence. Big gastrin is a hormone produced by G cells and can be found inside of the stomach. G-34 promotes the secretion of gastric acid in dogs. In dogs, the half life of this peptide is between 14.7 and 16.8 minutes. In humans, an over production of this hormone by gastrinomas leads to Zollinger–Ellison syndrome.
Expansion of the bone marrow in the developing child leads to a distinctive facial shape often referred to as "Chipmunk facies". Other skeletal changes include osteoporosis, growth retardation, and malformation of the spine. People with thalassemia can get too much iron in their bodies, either from the disease itself as RBCs are destroyed, or as a consequence of frequent blood transfusions. Excess iron is not excreted, but forms toxic non-transferrin-bound iron. This can lead to organ damage, potentially affecting the heart, liver, endocrine system, bones and spleen. Symptoms include an irregular heartbeat, cardiomyopathy, cirrhosis of the liver, hypothyroidism, delayed puberty and fertility problems, brittle and deformed bones, and an enlarged spleen. The spleen is the organ which removes damaged red blood cells from circulation; in thalassemia patients it is abnormally active, causing it to enlarge and possibly become hyperactive, a condition called hypersplenism. The immune system can become compromised in a number of ways; anemia, iron overload, and hypersplenism may affect the immune response and increase the risk of severe infection.
Sources: en.wikipedia.org
Cl2 + H2O ⇌ HClO + HCl Cl2 + 4 OH− ⇌ 2 ClO− + 2 H2O + 2 e− Cl2 + 2 e− ⇌ 2 Cl− When acids are added to aqueous salts of hypochlorous acid (such as sodium hypochlorite in commercial bleach solution), the resultant reaction is driven to the left, and chlorine gas is formed. Thus, the formation of stable hypochlorite bleaches is facilitated by dissolving chlorine gas into basic water solutions, such as sodium hydroxide. The acid can also be prepared by dissolving dichlorine monoxide in water; under standard aqueous conditions, anhydrous hypochlorous acid is currently impossible to prepare due to the readily reversible equilibrium between it and its anhydride:
It's possible that hackers have gotten into administrative computer systems of utility companies, but says those aren't linked to the equipment controlling the grid, at least not in developed countries. [Schmidt] has never heard that the grid itself has been hacked. In June 2019, Russia said that its electrical grid has been under cyber-attack by the United States. The New York Times reported that American hackers from the United States Cyber Command planted malware potentially capable of disrupting the Russian electrical grid.
=== Gr–Gu === Sam Granick (1909–1977). American biochemist at the Rockefeller University, known for his studies of ferritin and iron metabolism. Member Natl. Acad. Sci. USA. David E. Green (1910–1983). American biochemist at the University of Wisconsin, pioneer in the study of enzymes involved in oxidative phosphorylation. Member Natl. Acad. Sci. USA. Rowena Green Matthews (b. 1938). American biochemist at the University of Michigan Ann Arbor, working on the role of organic cofactors of enzymes, especially folic acid and cobalamin. Member Natl. Acad. Sci. USA. Lewis Joel Greene (b. 1934), American-Brazilian biochemist at the University of São Paulo, known for studies of protein chemistry. François Gros (1925–2022). French biologist and pioneer of cellular biochemistry at the French Academy of Sciences. Kun-Liang Guan (b. 1963). Chinese-American biochemist at the University of Michigan who works on gene regulation. F. Peter Guengerich (b. 1949). Biochemist and toxicologist at Vanderbilt University, working on cytochromes P450, DNA damage and carcinogenesis, and drug metabolism. Note. His personal Wikipedia page is very uninformative. Joan Guinovart (1947–2025). Spanish biochemist at the Institute for Research in Biomedicine (IRB Barcelona) known for studies of glycogen. Irwin Gunsalus (1912–2008). American biochemist at the University of Illinois, who discovered lipoic acid. He coauthored The Bacteria: A Treatise on Structure and Function with Roger Y. Stanier, a highly influential five-volume work. Member Natl. Acad. Sci. USA. Herbert Gutfreund FRS (1921–2021).
Sources: en.wikipedia.org
=== Catabolism === Catabolism of cardiolipin may happen by the catalysis of phospholipase A2 (PLA) to remove fatty acyl groups. Phospholipase D (PLD) in the mitochondrion hydrolyses cardiolipin to phosphatidic acid.
This stage of the aerobic system occurs on the cristae (infoldings of the membrane of the mitochondria). The reaction of each NADH in this electron transport chain provides enough energy for 3 molecules of ATP, while reaction of FADH2 yields 2 molecules of ATP. This means that 10 total NADH molecules allow the regeneration of 30 ATP, and 2 FADH2 molecules allow for 4 ATP molecules to be regenerated (in total 34 ATP from oxidative phosphorylation, plus 4 from the previous two stages, producing a total of 38 ATP in the aerobic system). NADH and FADH2 are oxidized to allow the NAD+ and FAD to be reused in the aerobic system, while electrons and hydrogen ions are accepted by oxygen to produce water, a harmless byproduct.
Many Irish nationalists sympathised with the Boers as oppressed by British imperialism, much like they viewed themselves. Irish miners already in the Transvaal at the start of the war formed the nucleus of two Irish commandos. The Second Irish Brigade was headed by an Australian of Irish parents, Colonel Arthur Lynch. Groups of Irish volunteers went to fight with the Boers—despite the fact that there were many Irish troops fighting in the British army, including the Royal Dublin Fusiliers. In Britain, the "Pro-Boer" campaign expanded, with writers often idealising the Boer society. The war highlighted the dangers of Britain's policy of non-alignment and deepened her isolation. The 1900 UK general election, also known as the "Khaki election", was called by the Prime Minister, Lord Salisbury, on the back of British victories. There was much enthusiasm for the war at this point, resulting in a victory for the Conservative government. However, support waned as it became apparent the war would not be easy and it dragged on, partially contributing to the Conservatives' spectacular defeat in 1906. There was outrage at scorched earth tactics and conditions in the concentration camps. It became apparent there were serious problems with public health in Britain as up to 40% of recruits in Britain were unfit for conscription, and suffered from medical problems such as rickets and other poverty-related illnesses. This came at a time of increasing concern for the poor in Britain. 22,000 Empire troops were killed.
Props of the Gravity Gun and Portal Gun are popular items for both cosplayers and collectors. Notable examples include two film-quality replicas by Australian artist Harrison Krix, which were auctioned for charity in 2010 and 2011.
Sources: en.wikipedia.org
It is associated with the melanocortin receptor family, particularly subtypes found in the central nervous system. This interaction is separate from the adrenal pathway activated by full-length ACTH.
Peptidases degrade the compound within minutes in circulation. This short half-life is one reason nasal delivery is used, placing the substance close to the olfactory and trigeminal pathways.
No large multicenter trials have been published in English-language journals. The existing human evidence consists mainly of smaller studies conducted in Russia, which limits generalization.
Semax is a synthetic seven-amino-acid peptide derived from a fragment of corticotropin. It is used in Russia as a nasal preparation, while elsewhere it is studied as a research compound. It is not approved as a medicine in most countries.