methionine sulfoxide raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-07. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
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.
Laboratory work points toward modulation of neurotrophic signaling, particularly expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal tissue. Studies also describe effects on monoamine turnover, inflammatory mediators, and oxidative markers. These observations come mainly from animal models and cultured cells, so the causal chain in humans is not firmly established. Whether the reported molecular changes translate into measurable clinical benefit is an open question. Reviews generally present the mechanism as plausible rather than demonstrated.
常规纯度与身份确认依赖反相高效液相色谱，并辅以质谱测定分子量。氨基酸组成分析可用于验证序列构成，肽图分析则能进一步定位修饰或降解产物。杂质谱通常关注缺失序列肽、截短片段和氧化产物。不同方法的检出限并不相同，因此各实验室报告的纯度数值不宜直接横向比较。
多数实验室与市售的 Semax 以冻干粉形式提供。冻干粉通常建议保存在 -20 °C 或更低温度下，同时避免光照与反复升温。短期运输有时采用冷藏条件，但长期保存仍以冷冻为主。分包操作应尽量减少开盖次数，以降低吸湿和微生物污染的风险。开封后若未一次用完，建议在干燥环境中密封并尽快放回低温储存。
Laboratory descriptions of the material are consistent across suppliers. It appears as a white to off-white lyophilized powder that dissolves readily in water and in polar organic solvents such as dimethyl sulfoxide. Aqueous solutions are clear and colorless at low concentrations. Because the peptide contains methionine, oxidation at the sulfur atom is a recognized degradation pathway, and handling notes usually call for protected, desiccated storage. Reported purity for research-grade lots is generally above 95 percent as measured by reversed-phase high-performance liquid chromatography.
The compound is registered in Russia as a pharmaceutical product, most commonly formulated as a nasal solution, and has been used in that setting since the 1990s. Outside that jurisdiction it is generally handled as a research chemical rather than an approved medicine. Regulatory status therefore differs sharply between countries, and material sold internationally may not correspond to the Russian pharmaceutical formulation. Documentation with commercial samples is typically limited to a certificate of analysis covering purity and identity, not clinical status or local legal classification.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It corresponds to the ACTH(4-7) fragment extended at the C-terminus by a Pro-Gly-Pro tripeptide, an addition intended to slow enzymatic breakdown. The molecular formula is C37H51N9O10S and the molecular mass is approximately 814 daltons. In the literature it is often described as an ACTH(4-10) analog, although that label reflects a naming convention as much as a precise structural relationship. The compound was developed in Russia and remains most closely associated with that research tradition.
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。
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。
== History == Brucella canis was first discovered in the United States by Leland Carmichael in 1966, when the bacterium was identified in canine vaginal discharge and the tissues from mass abortions in beagles. B. canis was said to be a biovar of B. suis. With recent research, PCR assay data was able to contradict B. canis and B. suis. PCR data showed a complete difference between the two strains along with B. suis biovars unattained from B. canis DNA. PCR assays have been proven beneficial when differentiating between Brucella strains and vaccine strains. Investigations into the bacterium revealed that domestic dogs are primarily affected along with other canine species. B. canis causes reproductive issues in female dogs, usually in the form of late-term spontaneous abortions. While in males, epididymitis, orchitis, and infertility were observed due to the bacterium. During the 1970s and 1980s, B. canis was reported in North America, Europe, and Asia. The reports were mainly from commercial breeding kennels wherein the bacterium can easily spread. Increase in infections were also attributed to the growing adoption of dogs as pets. By the 2000s, molecular analysis revealed that B. canis is unique from other Brucella species, categorized as a naturally occurring rough species that needs an anti-rough lipopolysaccharide reagent for detection. B. canis has been recognized as a growing zoonotic risk worldwide, having the ability to infect humans. Laboratory exposure or contact with pet dogs that had aborted fetuses were the main sources of exposure to the bacterium.
Vasoconstriction (narrowing of blood vessels) and vascular smooth muscle hypertrophy (enlargement) induced by ATII may lead to increased blood pressure and hypertension. Further, constriction of the efferent arterioles of the kidney leads to increased perfusion pressure in the glomeruli. It contributes to ventricular remodeling and ventricular hypertrophy of the heart through stimulation of the proto-oncogenes c-fos, c-jun, c-myc, transforming growth factor beta (TGF-B), through fibrogenesis and apoptosis (programmed cell death). Stimulation by ATII of the adrenal cortex to release aldosterone, a hormone that acts on kidney tubules, causes sodium and chloride ions retention and potassium excretion. Sodium is a "water-holding" ion, so water is also retained, which leads to increased blood volume, hence an increase in blood pressure. Stimulation of the posterior pituitary to release vasopressin (antidiuretic hormone, ADH) also acts on the kidneys to increase water retention. If ADH production is excessive in heart failure, Na+ level in the plasma may fall (hyponatremia), and this is a sign of increased risk of death in heart failure patients. A decrease renal protein kinase C During the course of ACE inhibitor use, the production of ATII is decreased, which prevents aldosterone release from the adrenal cortex. This allows the kidney to excrete sodium ions along with water, and retain potassium ions. This decreases blood volume, leading to decreased blood pressure.
Cigarette smoking has been found to affect global epigenetic regulation of transcription across tissue types. Studies have shown differences in epigenetic markers such as DNA methylation, histone modifications and miRNA expression between smokers and non-smokers. Similar differences exist in children whose mothers smoked during pregnancy. These epigenetic effects are thought to be linked to many of negative health effects associated with smoking. Studies have shown an association between prenatal exposure to environmental tobacco smoke and conduct disorder in children. As well, postnatal tobacco smoke exposure may cause similar behavioral problems in children.
=== 9 April === Ukraine started electricity exports for the first time since six months after the invasion. Energy exports had been stopped due to multiple strikes on the electrical infrastructure. Ukrainian Energy Minister Herman Halushchenko stated that the electrical system had been producing extra capacity for almost two months.
Sources: en.wikipedia.org
Side effects are similar to those of morphine, but due to pentazocine's action at the κ-opioid receptor, it is more likely to invoke psychotomimetic effects. High dose may cause high blood pressure or high heart rate. It may also increase cardiac work after myocardial infarction when given intravenously and hence this use should be avoided where possible. Respiratory depression is a common side effect, but is subject to a ceiling effect, such that at a certain dose the degree of respiratory depression will no longer increase with dose increases. Albeit rarely, pentazocine has been associated with agranulocytosis, erythema multiforme and toxic epidermal necrolysis.
Primary cells are those directly isolated from host tissue. These cells provide an ex-vivo model of cell behavior without any genetic, epigenetic, or developmental changes; making them a closer replication of in-vivo conditions than cells derived from other methods. This constraint however, can also make studying them difficult. These are mature cells, often terminally differentiated, meaning that for many cell types proliferation is difficult or impossible. Additionally, the microenvironments these cells exist in are highly specialized, often making replication of these conditions difficult. Secondary cells are a portion of cells from a primary culture is moved to a new repository/vessel to continue being cultured. Medium from the primary culture is removed, the cells that are desired to be transferred are obtained, and then cultured in a new vessel with fresh growth medium. A secondary cell culture is useful in order to ensure that cells have both the room and nutrients that they require to grow. Secondary cultures are most notably used in any scenario in which a larger quantity of cells than can be found in the primary culture is desired. Secondary cells share the constraints of primary cells (see above) but have an added risk of contamination when transferring to a new vessel.
=== Non-beverage uses === Instant coffee is used as a flavouring for baked goods, confections, ice creams and food such as stews. Instant coffee is one of the possible ingredients in Caffenol, a non-toxic black-and-white photographic developer using standard household items developed in 1995 by a photographic chemistry class at Rochester Institute of Technology. In crafts, instant coffee can be used to stain paper to look aged.
=== Gelling agents === Agar, a gelatinous substance derived from red algae, has a number of commercial uses. It is a good medium on which to grow bacteria and fungi, as most microorganisms cannot digest agar. Alginic acid, or alginate, is extracted from brown algae. Its uses range from gelling agents in food, to medical dressings. Alginic acid also has been used in the field of biotechnology as a biocompatible medium for cell encapsulation and cell immobilization. Molecular cuisine is also a user of the substance for its gelling properties, by which it becomes a delivery vehicle for flavours.
As a medication, it is used to treat several conditions, including allergic reaction anaphylaxis, cardiac arrest, and superficial bleeding. Inhaled adrenaline may be used to improve the symptoms of croup. It may also be used for asthma when other treatments are not effective. It is given intravenously, by injection into a muscle, by inhalation, or by injection just under the skin. Common side effects include shakiness, anxiety, and sweating. A fast heart rate and high blood pressure may occur. Occasionally it may result in an abnormal heart rhythm. While the safety of its use during pregnancy and breastfeeding is unclear, the benefits to the mother must be taken into account. A case has been made for the use of adrenaline infusion in place of the widely accepted treatment of inotropes for preterm infants with clinical cardiovascular compromise. Although sufficient data strongly recommends adrenaline infusions as a viable treatment, more trials are needed to conclusively determine that these infusions will successfully reduce morbidity and mortality rates among preterm, cardiovascularly compromised infants. Epinephrine can also be used to treat open-angle glaucoma, as it increases the outflow of aqueous humor from the eye, which lowers intraocular pressure.
Sources: en.wikipedia.org
== Structure == Aquasomes form a three-layered structure, made of a polyhydroxy oligomer coated core upon which the drug is loaded. The biochemically active molecules are able to interact with the coated core through different Van der Waal forces, entropic forces, and ionic and non-covalent bonds. The structure of aquasomes enables them to carry a variety of substrates (chemicals), facilitating applications such as protein and peptide delivery and protection, and the delivery of nucleic acids for gene therapy applications. Aquasomes' solid core, made of ceramic or polymeric material, is attributed to the structural stability of the nanoparticle itself, and can result in improved solubility and biocompatibility of the drug. Different core designs have also been shown to affect the controlled release properties of the drug molecule. A commonly used core material is the ceramic calcium phosphate, which naturally occurs in the body. Hydroxyapatite, which is found in bone, is another commonly used core material. Hydroxyapatite cores have been shown to contribute to targeted delivery of encapsulated hepatitis B antigens intracellularly. The second layer of aquasomes is the carbohydrate coat, onto which the drug is adsorbed. Due to carbohydrate's action as a dehydroprotectant, it has been shown to function as a natural stabilizer to preserve the conformation (shape) of soft drugs. The dehydroprotectant property of the carbohydrate coat also enables protection of the biochemically active molecule from dehydration and protein degradation.
== Physiology and industrial uses == Rhizopus oryzae is involved in steroid transformations and it produces 4-desmethyl steroids which has been useful in the fermentation industry. The carbon sources does influence the ratio of polar and neutral lipids. The mycelium found in R. oryzae contains lipids and the highest lipid content occurs when grown on fructose. The highest unsaturated fatty acid content is observed at 30 °C and lowest at 15 °C. Proteolytic properties have been observed well under the conditions of pH 7 at 35 °C. Pyridozine and thiamine prefer proteinase production. R. oryzae can degrade aflatoxin A1 to isomeric hydroxy compounds and aflatoxin G1 to fluorescent metabolite aflatoxin A1. There are various factors that influence the production of dextro-lactic acids, fumaric acid, and metabolism of R. oryzae. For examples, in 40 °C there is more favorable growth for glucose consumption, however this influenced production of d-lactic acid production negatively. Glucose concentration of 15% is needed for optimal production of d-lactic acid. Fumaric acid production was suppressed in media containing more than 6 grams of NH4NO3 per liter and is favorable to d-lactic acid production. Rhizopus oryzae is considered GRAS by the FDA and thus recognized as safe to use industrially as it can consume a range of carbon sources. During fermentation. R. oryzae produce amylase, lipase, and protease activity to increase nutrient's ability to use many compounds as an energy and carbon source.
The main ingredients of the extracellular matrix are glycoproteins secreted by the cells. The most abundant glycoprotein in the ECM of most animal cells is collagen, which forms strong fibers outside the cells. In fact, collagen accounts for about 40% of the total protein in the human body. The collagen fibers are embedded in a network woven from proteoglycans. A proteoglycan molecule consists of a small core protein with many carbohydrate chains covalently attached, so that it may be up to 95% carbohydrate. Large proteoglycan complexes can form when hundreds of proteoglycans become noncovalently attached to a single long polysaccharide molecule. Some cells are attached to the ECM by still other ECM glycoproteins such as fibronectin. Fibronectin and other ECM proteins bind to cell surface receptor proteins called integrins that are built into the plasma membrane. Integrins span the membrane and bind on the cytoplasmic side to associated proteins attached to microfilaments of the cytoskeleton. The name integrin is based on the word integrate, integrins are in a position to transmit signals between the ECM and the cytoskeleton and thus to integrate changes occurring outside and inside the cell. Current research on fibronectin, other ECM molecules, and integrins is revealing the influential role of the ECM in the lives of cells. By communicating with a cell through integrins, the ECM can regulate a cell's behavior.
=== Withdrawal and dependence === Withdrawal symptoms typically occur 1–2 days after abruptly stopping gabapentin (almost unambiguously due to extended use and during a very short-term rebound phenomenon) — similar to, albeit less intense than most benzodiazepines. Agitation, confusion and disorientation are the most frequently reported, followed by gastrointestinal complaints and sweating, and more rare tremor, tachycardia, hypertension and insomnia. In some cases, users experience withdrawal seizures after chronic or semi-chronic use in the absence of periodic cycles or breaks during repeating and consecutive use. All these symptoms subside when gabapentin is re-instated or tapered off gradually at an appropriate rate. On its own, gabapentin appears not to have a substantial addictive power. In human and animal experiments, it shows limited to no rewarding effects. The vast majority of people abusing gabapentin are current or former abusers of opioids or sedatives. In these persons, gabapentin can boost the opioid "high" as well as decrease commonly experienced opioid-withdrawal symptoms such as anxiety.
== Medical uses == Terlipressin is indicated to improve kidney function in adults with hepatorenal syndrome with rapid reduction in kidney function. Indications for use include norepinephrine-resistant septic shock although, 2021 Surviving Sepsis Guidelines recommend against its use for adults with septic shock and hepatorenal syndrome. In addition, it is used to treat bleeding esophageal varices.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
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.