Everything below concerns synthetic heptapeptide. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2025-07-28. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
Semax is a synthetic heptapeptide whose sequence is Met-Glu-His-Phe-Pro-Gly-Pro. The first four residues correspond to the ACTH(4-10) fragment, while the terminal Pro-Gly-Pro extension was added to improve metabolic stability. Its molecular formula is C37H51N9O10S and its monoisotopic mass is approximately 813.9 Da. The compound is classified as a peptide research chemical and as a registered pharmaceutical product in Russia, but it does not hold marketing approval in the European Union or the United States. Naming conventions vary across supplier catalogs.
| Property | Value | Notes |
|---|---|---|
| Typical analytical method | Reversed-phase HPLC with UV detection | Separates target peptide from truncated and oxidised forms |
| Identity confirmation | LC-MS or ESI-MS | Compares observed and calculated molecular ion |
| Primary degradation route | Methionine oxidation | Forms the sulfoxide; monitored as an early-eluting peak |
| Short-term storage | 2 to 8 degrees Celsius | Applies to working vials and reconstituted portions |
| Common synonyms | ACTH(4–10) analogue, MEHFPGP | Descriptive names used in laboratory catalogues |
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。
溶液状态的稳定性明显低于冻干粉。肽类在水溶液中可能经历水解、氧化与聚集，其中甲硫氨酸和天冬酰胺等残基常是敏感位点。Semax 含有甲硫氨酸，因此氧化风险相对突出。工作液一般主张现配现用，或冷藏并在数日内用尽。缓冲液种类、pH 和离子强度都会影响降解速率，而关于最佳条件的公开数据并不统一。
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.
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.
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。
=== Multicellularity === Most bacterial species exist as single cells; others associate in characteristic patterns: Neisseria forms diploids (pairs), streptococci form chains, and staphylococci group together in "bunch of grapes" clusters. Bacteria can also group to form larger multicellular structures, such as the elongated filaments of Actinomycetota species, the aggregates of Myxobacteria species, and the complex hyphae of Streptomyces species. These multicellular structures are often only seen in certain conditions. For example, when starved of amino acids, myxobacteria detect surrounding cells in a process known as quorum sensing, migrate towards each other, and aggregate to form fruiting bodies up to 500 micrometres long and containing approximately 100,000 bacterial cells. In these fruiting bodies, the bacteria perform separate tasks; for example, about one in ten cells migrate to the top of a fruiting body and differentiate into a specialised dormant state called a myxospore, which is more resistant to drying and other adverse environmental conditions.
=== Column selection === The choice of column depends on the sample and the active measured. The main chemical attribute regarded when choosing a column is the polarity of the mixture, but functional groups can play a large part in column selection. The polarity of the sample must closely match the polarity of the column stationary phase to increase resolution and separation while reducing run time. The separation and run time also depends on the film thickness (of the stationary phase), the column diameter and the column length.
Citizens may teach and may be taught religion privately.' Among further restrictions, those adopted in 1929 included express prohibitions on a range of church activities, including meetings for organized Bible study. Both Christian and non-Christian establishments were shut down by the thousands in the 1920s and 1930s. By 1940, as many as 90% of the churches, synagogues, and mosques that had been operating in 1917 were closed; the majority of them were demolished or re-purposed for state needs with little concern for their historic and cultural value. More than 85,000 Orthodox priests were shot in 1937 alone. Only a twelfth of the Russian Orthodox Church's priests were left functioning in their parishes by 1941. In the period between 1927 and 1940, the number of Orthodox Churches in Russia fell from 29,584 to less than 500 (1.7%). The Soviet Union was officially a secular state, but a 'government-sponsored program of forced conversion to atheism' was conducted under the doctrine of state atheism. The government targeted religions based on state interests, and while most organized religions were never outlawed, religious property was confiscated, believers were harassed, and religion was ridiculed while atheism was propagated in schools. In 1925, the government founded the League of Militant Atheists to intensify the propaganda campaign.
=== Medical Nursing Homes === Medical nursing homes, including residential treatment centers and geriatric care facilities, are health care institutions which have accommodation facilities and which engage in providing short-term or long-term medical treatment of a general or specialized nature not performed by hospitals to inpatients with any of a wide variety of medical conditions.
Sources: en.wikipedia.org
In 2019, the European Medicines Agency's Pharmacovigilance Risk Assessment Committee (PRAC) recommended that product labels for all SSRIs and SNRIs, including sertraline, be updated to state that sexual dysfunction may be long-lasting even after treatment is stopped. Health Canada followed with similar label updates in 2021. In 2024, Australia's Therapeutic Goods Administration aligned all SSRI and SNRI product information to reflect this risk, noting that sertraline already carried a warning about persistent sexual dysfunction.
The Zostavax vaccine (both single dose and two-dose regime) is likely effective at protecting people from herpes zoster disease for a duration of up to three years. The degree of longer term protection (beyond 4 years from the initial vaccination) is not clear. The need for re-vaccination after the first full vaccine schedule is complete remains to be confirmed. Zostavax was shown to reduce the incidence of shingles by 51% in a study of 38,000 adults aged 60 and older who received the vaccine. The vaccine also reduced by 67% the number of cases of postherpetic neuralgia (PHN) and reduced the severity and duration of pain and discomfort associated with shingles, by 61%. The FDA originally recommended it for individuals 60 years of age or older who are not severely allergic to any of its components and who meet the following requirements:
In chemistry, a molecule or ion is called chiral () if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes. This geometric property is called chirality (). The terms are derived from Ancient Greek χείρ (cheir) 'hand'; which is the canonical example of an object with this property. A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right-handed" or "left-handed" by their absolute configuration or some other criterion. The two enantiomers have the same chemical properties, except when reacting with other chiral compounds. They also have the same physical properties, except that they often have opposite optical activities. A homogeneous mixture of the two enantiomers in equal parts, a racemic mixture, differs chemically and physically from the pure enantiomers. Chiral molecules will usually have a stereogenic element from which chirality arises. The most common type of stereogenic element is a stereogenic center, or stereocenter. In the case of organic compounds, stereocenters most frequently take the form of a carbon atom with four distinct groups attached to it in a tetrahedral geometry. Less commonly, other atoms like N, P, S, and Si can also serve as stereocenters, provided they have four distinct substituents (including lone pair electrons) attached to them.
Sources: en.wikipedia.org
Satiety value is the degree at which food gives a human the feeling of satiety per calorie. The concept of the Satiety Value and Satiety Index was developed by Australian researcher and doctor, Susanna Holt. Highest satiety value is expected when the food that remains in the stomach for a longer period produces greatest functional activity of the organ. Foods with the most satiation per calorie are often:
=== Coagulation factor disorders === The best-known coagulation factor disorders are the hemophilias. The three main forms are hemophilia A (factor VIII deficiency), hemophilia B (factor IX deficiency or "Christmas disease") and hemophilia C (factor XI deficiency, mild bleeding tendency). Von Willebrand disease (which behaves more like a platelet disorder except in severe cases), is the most common hereditary bleeding disorder and is characterized as being inherited autosomal recessive or dominant. In this disease, there is a defect in von Willebrand factor (vWF), which mediates the binding of glycoprotein Ib (GPIb) to collagen. This binding helps mediate the activation of platelets and formation of primary hemostasis. In acute or chronic liver failure, there is insufficient production of coagulation factors, possibly increasing risk of bleeding during surgery. Thrombosis is the pathological development of blood clots. These clots may break free and become mobile, forming an embolus or grow to such a size that occludes the vessel in which it developed. An embolism is said to occur when the thrombus (blood clot) becomes a mobile embolus and migrates to another part of the body, interfering with blood circulation and hence impairing organ function downstream of the occlusion. This causes ischemia and often leads to ischemic necrosis of tissue. Most cases of venous thrombosis are due to acquired states (older age, surgery, cancer, immobility).
Save for a brief mention in the Barrie Examiner, it was the first time Carrey received significant mainstream corporate media coverage and the glowing praise in one of Canada's highest-circulation dailies created demand for his impressionist stand-up act throughout the country. In April 1981, Carrey appeared in an episode of the televised stand-up show An Evening at the Improv. That summer, he landed one of the main roles in Introducing... Janet, a made-for-TV movie that premiered in September 1981 on the CBC drawing more than a million viewers for its first airing in Canada. Playing a struggling impressionist comic Tony Moroni, it was Carrey's first acting role. The CBC promotion the movie had received as well its subsequent high nationwide viewership further solidified the youngster's comedic status in the country; by the time the movie finished its CBC run of repeats several years later, its title for the home video release on VHS was changed to Rubberface in order to take advantage of the comic's by then established prominence for doing elaborate contortionist impressions. Making more comedy club appearances in the United States, Carrey was noticed by comedian Rodney Dangerfield who signed Carrey to open his tour performances. By December 1981, a well-known comic in Canada, Toronto Star reported about Carrey waiting for a United States work permit having received interest from Johnny Carson's Tonight Show, largely off his reputation from Canada.
Sources: en.wikipedia.org
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.
Oxidation of the methionine residue to the sulfoxide is a frequently reported change, and it usually appears as an earlier-eluting peak in reversed-phase chromatography. Backbone hydrolysis products can also accumulate in aqueous solution.
Liquid chromatography coupled with mass spectrometry is the usual approach, because the observed molecular ion can be compared with a calculated mass of about 813.9 Da. Retention time alone does not establish identity.
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.