This is a working overview of heptapeptide, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
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.
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.
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.
| 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. 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.
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.
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。
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.
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.
=== Pathways === Until recently, necrosis was thought to be an unregulated process. However, there are two broad pathways in which necrosis may occur in an organism. The first of these two pathways initially involves oncosis, where swelling of the cells occurs. Affected cells then proceed to blebbing, and this is followed by pyknosis, in which nuclear shrinkage transpires. In the final step of this pathway cell nuclei are dissolved into the cytoplasm, which is referred to as karyolysis. The second pathway is a secondary form of necrosis that is shown to occur after apoptosis and budding. In these cellular changes of necrosis, the nucleus breaks into fragments (known as karyorrhexis).
Following this in 1994, Teuscher and Lindequist defined biogenic substances as "chemical compounds which are synthesised by living organisms and which, if they exceed certain concentrations, cause temporary or permanent damage or even death of other organisms by chemical or physicochemical effects" in their book, Biogene Gifte. This emphasis in research and classification on the toxicity of biogenic substances was partly due to the cytotoxicity-directed screening assays that were used to detect the biologically active compounds. The diversity of biogenic products has since been expanded from cytotoxic substances through the use of alternative pharmaceutical and industrial assays.
20 September 74 of 75 persons on an Air Vietnam Douglas DC-4 were killed after a mid-air collision with a USAF F-4 Phantom. Both aircraft were approaching Da Nang Air Base when the F-4 clipped the wing of the DC-4 causing it to crash into a field, killing two farmers on the ground. The PAVN/VC attacked Tu Van refugee center in Quảng Ngãi Province, killing 8 persons and wounding two, all families of local People's Self-Defense Force members. In nearby Bình Sơn District, eight members of a police official's family were killed.
Any condition that results in the production of abnormal hemoglobin is included under the broad category of hemoglobinopathies. Worldwide, it is estimated that 7% of the population may carry a hemoglobinopathy with clinical significance. The most well known condition in this group is sickle cell disease. Newborn screening for a large number of hemoglobinopathies is done by detecting abnormal patterns using isoelectric focusing, which can detect many different types of abnormal hemoglobins. In the United States, newborn screening for sickle cell disease was recommended for all infants in 1987, however it was not implemented in all 50 states until 2006. Early identification of individuals with sickle cell disease and other hemoglobinopathies allows treatment to be initiated in a timely fashion. Penicillin has been used in children with sickle cell disease, and blood transfusions are used for patients identified with severe thalassemia.
Sources: en.wikipedia.org
DiCaprio rejected a role in Boogie Nights (1997) to star opposite Kate Winslet in James Cameron's Titanic as members of different social classes who fall in love aboard RMS Titanic. DiCaprio had doubts, but was encouraged by Cameron to pursue the part. With a production budget of more than $200 million, Titanic was the most expensive in history at the time. It became the highest-grossing film at the time, earning more than $2.1 billion in box-office receipts worldwide. It won 11 Academy Awards—the most wins for any film—including Best Picture; DiCaprio's failure to gain a nomination led to a protest against the Academy of Motion Picture Arts and Sciences by more than 200 fans. He was nominated for other high-profile awards, including a Golden Globe Award for Best Actor.
Some women complain of a "small penis" when the trim procedure is performed, owing to the un-addressed clitoral hood tissue and completely removed (amputated) labia minor. Most plastic surgeons do not perform this procedure, and instead favor the extended wedge approach, which is technically more demanding, but produces a more natural result and is able to create a natural and proportioned appearance to the vulva. Reconstructive procedures are often required after the trim (amputation) labiaplasty.
FAD, or flavin adenine dinucleotide, is a prosthetic group (a non-polypeptide unit bound to a protein that is required for function) that consists of an adenine nucleotide and a flavin mononucleotide. FAD is a unique electron acceptor. Its fully reduced form is FADH2 (known as the hydroquinone form), but FAD can also be partially oxidized as FADH by either reducing FAD or oxidizing FADH2. Dehydrogenases typically fully reduce FAD to FADH2. The production of FADH is rare. The double-bonded nitrogen atoms in FAD make it a good acceptor in taking two hydrogen atoms from a substrate. Because it takes two atoms rather than one, FAD is often involved when a double bond is formed in the newly oxidized substrate. FAD is unique because it is reduced by two electrons and two protons, as opposed to both NAD+ and NADP, which only take one proton.
Sources: en.wikipedia.org
Normally pathogenic bacteria are weakened so they are no longer pathogenic. Commensal or food-grade bacteria which are not pathogenic. Using bacterial surface display of antigens is a valuable alternative to conventional vaccine design for various reasons, one of them being that the proteins expressed on the bacterial cell surface can act favourably as an adjuvant. Conventional vaccines require the addition of adjuvants. Another advantage of generating vaccines using bacterial display systems is that the whole bacterial cell can be incorporated in the live vaccine Unlike bacteriophage display systems which are generally used in vaccine development to find unknown epitopes, bacterial display systems are used to express known epitopes and the cells act as a vaccine delivery system.
=== Biosynthesis === It is believed that the biosynthesis of guanacastepenes occurs via the mevalonate pathway. This pathway begins with acetyl-CoA and yields both isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP). IPP and DMAPP are then converted into geranylgeranyl pyrophosphate (GGPP), the most important diterpene precursor. A cationic cyclization cascade converts GGPP into the macrocyclic intermediate β-araneosene and ultimately into the dolabellane skeleton. Dolabellane is then rearranged into the neodolabellane skeleton via stereospecific hydride and methyl shifts, thereby fixing the stereochemistry at C11 and C12 and shifting the C15 methyl group across the ring fusion. The carbon skeleton of Guanacastepene A is closely related to the dolastane and neodolabellane families. Therefore, it is assumed that the biogenesis of dolastanes proceeds via a further intramolecular cyclization of the dolabellane-derived cation, resulting in the tricyclic [5-7-6]-dolastane (guanacastane) skeleton. This basic framework is diversified through a series of oxidation reactions in which the characteristic functional groups of guanacastepenes are incorporated. The guanacastepenes characterized to date represent only a fraction of the metabolites present in the CR115 extract. The tricyclic guanacastepenes A, B, and C are considered the simplest members of this family; successive oxidation and functionalization are thought to lead to the formation of structurally more complex ring systems.
=== Self-medication theory === The self-medication theory suggests that people with severe mental illnesses misuse substances in order to relieve a specific set of symptoms and counter the negative side-effects of antipsychotic medication. Khantizan proposes that substances are not randomly chosen, but are specifically selected for their effects. For example, using stimulants such as nicotine or amphetamines can be used to combat the sedation that can be caused by higher doses of certain types of antipsychotic medication. Conversely, some people taking medications with a stimulant effect such as the SNRI antidepressants Effexor (venlafaxine) or Wellbutrin (bupropion) may seek out benzodiazepines or opioid narcotics to counter the anxiety and insomnia that such medications sometimes evoke. Some studies show that nicotine administration can be effective for reducing motor side-effects of antipsychotics, with both bradykinesia (stiff muscles) and dyskinesia (involuntary movement) being prevented.
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.
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.