neurotrophic factor comes up often in conversation and rarely with the context attached. Here we lay out the basics in order, then work through the practical considerations.
Updated 2026-02-05. Numbers and descriptions here follow the published literature rather than marketing material.
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.
Development took place during the 1980s at institutes of the Russian Academy of Sciences, where peptide fragments of ACTH were screened for cognitive and neuroprotective effects. The compound received regulatory approval in Russia as a nasal preparation, marketed for conditions such as ischemic stroke, transient ischemic attacks, and optic nerve disorders. Registration in other countries has not followed. Most published clinical reports originate from a small number of Russian research groups, and independent replication outside that setting remains limited. The regulatory status therefore differs sharply between Russia and the rest of the world.
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.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
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。
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.
== Use and effects == A phase 1 dose-ranging clinical trial found that zalsupindole is non-hallucinogenic in humans across a dose range of 2 to 360 mg orally. Nonetheless, it produced changes in brain function as measured by quantitative electroencephalography (qEEG).
It has to be appreciated that at the time the menace of doping for the health of athletes or of the purity of competition had yet to enter the morals because, after this marathon, the official race report said: The marathon has shown from a medical point of view how drugs can be very useful to athletes in long-distance races. Hicks was, in the phrase of the time, "between life and death" but recovered, collected his gold medal a few days later, and lived until 1952. Nonetheless, he never again took part in athletics.
As enologists began better understanding the science of fermentation, nitrogen was identified as a principal nutrient and winemakers as early as the 1900s began adding ammonium salts to their must. Urea was also used as an early nitrogen supplement but research linking it to the development of ethyl carbamate has led to its banning in many countries, including the United States since 1990. There are many types of nitrogen supplements available for winemakers to use. Most of them are complex formulations that include nitrogen (from either amino acids or ammonium salts) along with vitamins, minerals and other growth factors and sold under brand names like Go-Ferm, Superfood, Fermaid K (the later two also containing some DAP). Amino acids can be added directly to the must though as of 2010 only glycine is permitted to be added to must in the United States.
. There is general formula for friction force in a liquid: The vector differential of friction force is equal the viscosity tensor increased on vector product differential of the area vector of adjoining a liquid layers and rotor of velocity:
Sources: en.wikipedia.org
== External links == GLUT4+Protein at the U.S. National Library of Medicine Medical Subject Headings (MeSH) USCD—Nature molecule pages: The signaling pathway, "GLUT4"; contains a high-resolution network map. Accessed 25 December 2009.
==== Yeasts ==== Actin's cytoskeleton is key to the processes of endocytosis, cytokinesis, determination of cell polarity and morphogenesis in yeasts. In addition to relying on actin, these processes involve 20 or 30 associated proteins, which all have a high degree of evolutionary conservation, along with many signalling molecules. Together these elements allow a spatially and temporally modulated assembly that defines a cell's response to both internal and external stimuli. Yeasts contain three main elements that are associated with actin: patches, cables, and rings. Despite not being present for long, these structures are subject to a dynamic equilibrium due to continual polymerization and depolymerization. They possess a number of accessory proteins including ADF/cofilin, which has a molecular weight of 16kDa and is coded for by a single gene, called COF1; Aip1, a cofilin cofactor that promotes the disassembly of microfilaments; Srv2/CAP, a process regulator related to adenylate cyclase proteins; a profilin with a molecular weight of approximately 14 kDa that is related/associated with actin monomers; and twinfilin, a 40 kDa protein involved in the organization of patches.
== Methodology == Category 1: Stability (weighted 25% of total) Prevalence of summary offense Prevalence of violent crime Threat of terrorism Threat of war Threat of civil disorder Category 2: Healthcare (20%) Availability of private health care Quality of private healthcare Availability of publicly funded health care Quality of publicly funded health care Availability of over-the-counter drug World Bank's general health care indicators Category 3: Culture & Environment (25%) Humidity, temperature rating Discomfort of climate to travelers Transparency International's level of corruption Social or religious restrictions Level of censorship Sporting availability from 3 sport indicators Cultural availability from 4 cultural indicators Food and drink from 4 cultural indicators Consumer goods and services from product availability Category 4: Education (10%) Availability of private education Quality of private education World Bank's state school indicators Category 5: Infrastructure (20%) Street network quality Public transport quality International transportation service quality Availability of good quality housing Energy provision quality Water provision quality Telecommunications quality
=== Pseudomonas syringae pv. tomato strain DC3000 and Arabidopsis thaliana === As mentioned above, the genome of P. syringae pv. tomato DC3000 has been sequenced, and approximately 40 Hop (Hrp Outer Protein) effectors - pathogenic proteins that attenuate the host cell - have been identified. These 40 effectors are not recognized by A. thaliana thus making P. syringae pv. tomato DC3000 virulent against it - that is, P. syringae pv. tomato DC3000 is able to infect A. thaliana - thus A. thaliana is susceptible to this pathogen. Many gene-for-gene relationships have been identified using the two model organisms, P. syringae pv. tomato strain DC3000 and Arabidopsis. The gene-for-gene relationship describes the recognition of pathogenic avirulence (avr) genes by host resistance genes (R-genes). P. syringae pv. tomato DC3000 is a useful tool for studying avr: R-gene interactions in A. thaliana because it can be transformed with avr genes from other bacterial pathogens, and furthermore, because none of the endogenous hops genes is recognized by A. thaliana, any observed avr recognition identified using this model can be attributed to recognition of the introduced avr by A. thaliana. The transformation of P. syringae pv. tomato DC3000 with effectors from other pathogens have led to the identification of many R-genes in Arabidopsis to further advance knowledge of plant pathogen interactions.
=== Depression === A variety of meta-analyses have been conducted to evaluate the efficacy of paroxetine in depression. They have variously concluded that paroxetine is superior to placebo and that it is equivalent to other antidepressants. Despite this, there was no clear evidence that paroxetine was better or worse compared with other antidepressants at increasing response to treatment at any point in time.
Sources: en.wikipedia.org
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.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
Suppliers normally quote a percentage of total chromatographic peak area, most often from reversed-phase HPLC. That figure says nothing about what the remaining percentage contains, and it depends on the detection wavelength used. A mass spectrometry result is a separate and stronger check on identity.