Everything below concerns Lyophilized powder. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-11-17. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
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.
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。
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Free acid form of the heptapeptide; depends on terminal groups |
| Molecular mass | About 813.9 g/mol | Average mass used for mass spectrometry confirmation |
| Appearance | White to off-white solid | Supplied as a lyophilised powder; hygroscopic |
| Solubility class | Freely soluble in aqueous media | Water, saline, and phosphate buffers; limited organic solubility |
| Typical storage temperature | -20 degrees Celsius | Long term and dry; short working periods may use 2 to 8 degrees Celsius |
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.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
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.
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.
=== Hormonal === Inhibition of ceramide synthesis with myriocin in obese mice may lead to both improved leptin signaling and decreased insulin resistance by decreasing SOCS-3 expression. An elevated level of ceramide can cause insulin resistance by inhibiting the ability of insulin to activate the insulin signal transduction pathway and/or via the activation of JNK.
Sjögren's disease may be excluded in people with past head and neck radiation therapy, active hepatitis C confirmed with a positive PCR test, acquired immunodeficiency syndrome, sarcoidosis, amyloidosis, graft-versus-host disease, and IgG4-related disease. Patients using anticholinergic drugs must stop using them for some time before being evaluated for symptoms of dryness.
== Skene's gland == Because the Skene's gland and the male prostate act similarly by secreting prostate-specific antigen (PSA), which is an ejaculate protein produced in males, and of prostate-specific acid phosphatase, the Skene's gland is sometimes referred to as the "female prostate". Although homologous to the male prostate (developed from the same embryological tissues), various aspects of its development in relation to the male prostate are widely unknown and a matter of research.
Sources: en.wikipedia.org
==== Other uses ==== Sulfur fumigation could be used to disinfect wine barrels and prevent wine spoilage: In the mid-15th century, under the reign of Frederick III, several imperial decrees forbade the use of sulfur in wine barrels in Germany (thus implying that it was an attested practice). The ban was relaxed by his successor, Maximilian I. The practice then spread to France; in the 17th century, French wines were known to be sulfured when exported, French white wines being particularly affected. The Netherlands, importer of French wine, had their own sulfuring process using "allumettes hollandaises" (Dutch wicks), and were said to excessively sulfur the wine. That type of heavily sulfured wine was called "vin muet" in French, and "stomme" in Dutch, which both translate to "silent wine". Mixing some stomme with wine would make the wine sweeter, as well as making it last longer. However, as sulfuring was known to alter the taste and to potentially transfer impurities like arsenic to the wine, there were some health concerns around it. The Netherlands therefore decided to ban stomme in 1613, but the practice nevertheless perdured. In the late 18th century, furniture makers of German and Swiss origin in Pennsylvania, Maryland, Virginia and North Carolina used molten sulfur to produce decorative inlays. This type of inlay was mostly used on chests, schranks and clocks, but a wide range of surviving examples can be found, including tables, cupboards, cradles and many more.
Every polyhedron has a dihedral angle at every edge describing the relationship of the two faces that share that edge. This dihedral angle, also called the face angle, is measured as the internal angle with respect to the polyhedron. An angle of 0° means the face normal vectors are antiparallel and the faces overlap each other, which implies that it is part of a degenerate polyhedron. An angle of 180° means the faces are parallel, as in a tiling. An angle greater than 180° exists on concave portions of a polyhedron. Every dihedral angle in a polyhedron that is isotoxal and/or isohedral has the same value. This includes the 5 Platonic solids, the 13 Catalan solids, the 4 Kepler–Poinsot polyhedra, the 2 convex quasiregular polyhedra, and the 2 infinite families of bipyramids and trapezohedra.
2006 – Ada Yonath "for ingenious structural discoveries of the ribosomal machinery of peptide-bond formation and the light-driven primary processes in photosynthesis. 2022 – Bonnie L. Bassler and Carolyn R. Bertozzi "for their seminal contributions to understanding the chemistry of cellular communication and inventing chemical methodologies to study the role of carbohydrates, lipids, and proteins in such biological processes."
Sources: en.wikipedia.org
The enzyme uses molecular oxygen and reduced nicotinamide adenine dinucleotide phosphate (NADPH) to insert a hydroxy group into a specific position in one of the benzene rings of the starting material. It is a cytochrome P450 protein containing heme which acts as an oxidoreductase. The systematic name of this enzyme class is flavonoid,NADPH:oxygen oxidoreductase (3′-hydroxylating). Other names in common use include flavonoid 3′-hydroxylase, flavonoid 3-hydroxylase (erroneous), NADPH:flavonoid-3′-hydroxylase, and flavonoid 3-monooxygenase (erroneous). In palnts including Matthiola incana from which it was first characterised, it is part of the pathway to anthocyanins.
In chemical reaction engineering, "yield", "conversion" and "selectivity" are terms used to describe ratios of how much of a reactant has reacted—conversion, how much of a desired product was formed—yield, and how much desired product was formed in ratio to the undesired product—selectivity, represented as X, S, and Y. According to the Elements of Chemical Reaction Engineering manual, yield refers to the amount of a specific product formed per mole of reactant consumed. In chemistry, mole is used to describe quantities of reactants and products in chemical reactions. The Compendium of Chemical Terminology defined yield as the "ratio expressing the efficiency of a mass conversion process. The yield coefficient is defined as the amount of cell mass (kg) or product formed (kg,mol) related to the consumed substrate (carbon or nitrogen source or oxygen in kg or moles) or to the intracellular ATP production (moles)." In the section "Calculations of yields in the monitoring of reactions" in the 1996 4th edition of Vogel's Textbook of Practical Organic Chemistry (1978), the authors write that, "theoretical yield in an organic reaction is the weight of product which would be obtained if the reaction has proceeded to completion according to the chemical equation. The yield is the weight of the pure product which is isolated from the reaction." In 'the 1996 edition of Vogel's Textbook, percentage yield is expressed as,
Bachem Holding AG is a Swiss biotechnology company specializing in the development and manufacture of peptides and complex organic molecules for use as active pharmaceutical ingredients (APIs). The company focuses on peptide-based therapeutics, including large-scale commercial production and process development for pharmaceutical applications. It was founded in 1971 and is a subsidiary of Ingro Finanz AG. The head office is in Bubendorf in the canton of Basel-Landschaft. Bachem operates production facilities in Vionnaz (Switzerland), Vista and Torrance (United States), and St Helens (United Kingdom), as well as a sales and distribution site in Tokyo. Bachem is one of the largest manufacturers of peptide-based APIs globally, supplying pharmaceutical and biotechnology companies with products used in both clinical development and commercial therapies. In recent years, the company has expanded its manufacturing capacity, including new large-scale production facilities in Switzerland and the United States. At the end of 2025, the company employed 2,511 people, reported revenue of CHF 695.1 million, and net income of CHF 148.8 million.
Sources: en.wikipedia.org
It is described as a synthetic analogue of the ACTH(4–10) fragment, a short segment of adrenocorticotropic hormone. Its sequence differs from that fragment and includes two proline residues, which influence stability and behaviour in solution.
It appears in Russian pharmaceutical listings as a nasal formulation, but it is not an authorised medicine in the United States or the European Union. Outside those markets it is normally encountered as a research chemical rather than a prescription product.
Laboratory and animal work points to melanocortin signalling and changes in neurotrophic factor levels, especially brain-derived neurotrophic factor. The exact receptor targets and the degree to which these findings transfer to humans are still unresolved.
电喷雾或基质辅助激光解吸电离质谱是常用手段，测得的质子化离子质荷比可换算为分子量。结果与理论值落在合理误差内，才支持结构一致的判断。