A practical reference on peptide degradation: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2026-04-23 and is reviewed periodically as new material appears.
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.
Published research covers ischemic stroke, traumatic brain injury, cognitive impairment, optic nerve conditions and attention-related measures. Much of the human evidence comes from small trials conducted in one country, which limits how far the results generalize. Animal models supply the larger share of the data, and effects seen in rodents do not transfer automatically to people. Reviews have noted that methodological reporting is often incomplete, making it difficult to pool results or compare treatment schedules across studies.
Pharmacokinetic accounts emphasize rapid breakdown. After intravenous dosing the intact peptide disappears from blood within minutes, and nasal delivery produces low but measurable concentrations. Metabolites rather than the parent molecule may account for part of the observed activity, although the relative contribution is unresolved. Dosing in the literature varies widely and no optimal schedule has been agreed. These gaps are regularly cited as a reason the findings have not produced broad clinical adoption beyond the original research setting.
| 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 |
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.
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.
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。
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.
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.
Dehydrogenase enzymes transfer electrons from the substrate to an electron carrier; what carrier is used depends on the reaction taking place. Common electron acceptors used by this subclass are NAD+, FAD, and NADP+. Electron carriers are reduced in this process and considered oxidizers of the substrate. Electron carriers are coenzymes that are often referred to as "redox cofactors."
Proteins of interest can then be selectively bound to the ligands to separate them from other proteins, after which it can be eluted. The agarose beads used are typically of 4% and 6% densities with a high binding capacity for protein.
However, it is not structurally similar to a bird beak (or any "true" beak, for that matter), being fleshy instead of keratinous. Red blood cells in mammals lack a cell nucleus. In comparison, the red blood cells of other vertebrates have nuclei; the only known exceptions are salamanders of the genus Batrachoseps and fish of the genus Maurolicus. Caniforms like skunks and raccoons in North and South America and feliforms such as mongoose and civets in Asia and Africa have both evolved to fill the niche of small to medium omnivore/insectivore on their side of the world. Some species of mongoose and civet can even spray their attacker with musk similar to the skunk and some civets have also independently evolved similar markings to the raccoon such as the African civet. River dolphins of the three species that live exclusively in freshwater, live in different rivers: Ganges and Brahmaputra Rivers of India, the Yangtze River of China, and the Amazon River. Mitochondrial and nuclear DNA sequence analysis demonstrates the three are not related. Mangabeys comprise three different genera of Old World monkeys. The genera Lophocebus and Cercocebus resemble each other and were once thought to be closely related, so much so that all the species were in one genus. However, it is now known that Lophocebus is more closely related to baboons, while the Cercocebus is more closely related to the mandrill. Sperm whales and the microscopic copepods both use the same buoyancy control system.
Severe combined immunodeficiencies (SCIDs) are a rare group of genetic disorders characterized by the body's inability to create functional T cells and B cells. SCIDs are the most severe form of primary immunodeficiency, making their sufferers extremely vulnerable to infection due to their highly compromised immune system. There are at least seven different known genes in which mutations lead to a form of SCID, each of which has different clinical presentations. SCID involves defective antibody response due to either direct involvement with B lymphocytes or through improper B lymphocyte activation due to non-functional T-helper cells. Consequently, both "arms" (B cells and T cells) of the adaptive immune system are impaired due to a defect in one of several possible genes. Some SCID sufferers, such as David Vetter, have become famous for living in a sterile environment to avoid infection, leading to the name bubble boy disease and bubble baby disease. SCID patients are usually affected by severe bacterial, viral, or fungal infections early in life and often present with interstitial lung disease, chronic diarrhea, and failure to thrive. Ear infections, recurrent Pneumocystis jirovecii pneumonia, and profuse oral candidiasis commonly occur. These babies, if untreated, usually die within one year due to severe, recurrent infections unless they have undergone successful hematopoietic stem cell transplantation or gene therapy in clinical trials.
Sources: en.wikipedia.org
Ultrasound-assisted extractive electrospray ionization mass spectrometry (EESI-MS) has been developed at ETH Zurich (Switzerland) by Zhu, Chingin et al., (2008) for a rapid detection of melamine in untreated food samples. Ultrasounds are used to nebulize the melamine-containing liquids into a fine spray. The spray is then ionised by extractive electrospray ionisation (EESI) and analysed using tandem mass spectrometry (MS/MS). An analysis requires 30 seconds per sample. The limit of detection of melamine is a few nanograms of melamine per gram of milk. Huang et al. (2008) have also developed at Purdue University (US) a simpler instrumentation and a faster method by using a low-temperature plasma probe to ionize the samples. The major obstacles being solved, the ESI-MS technique allows now high-throughput analysis of melamine traces in complex mixtures. The Melaminometer was a hypothetical design for a synthetic biology circuit, to be used for detecting melamine and related chemical analogues such as cyanuric acid. The conceptual project is hosted at OpenWetWare as open source biology in collaboration with DIYbio and has been discussed in various newspapers in the context of homebrew biotechnology. As of October 2009, the design has not been verified. Because melamine resin is often used in food packaging and tableware, melamine at ppm level (1 part per million) in food and beverage has been reported due to migration from melamine-containing resins.
The high retail value of saffron is maintained on world markets because of labour-intensive harvesting methods, which require some 440,000 hand-picked saffron stigmas per kilogram (200,000 stigmas/lb) – equivalently, 150,000 crocus flowers per kilogram (70,000 flowers/lb). Forty hours of labour are needed to pick 150,000 flowers. One freshly picked crocus flower yields on average 30 mg of fresh saffron or 7 mg dried; roughly 150 flowers yield 1 g (1⁄32 oz) of dry saffron threads; to produce 12 g (7⁄16 oz) of dried saffron, 450 g (1 lb) of flowers are needed; the yield of dried spice from fresh saffron is only 13 g/kg (0.2 oz/lb).
Cold War 2 is a 2016 police procedural action thriller film written and directed by Longman Leung and Sunny Luk. A Hong Kong-Chinese co-production, the film is a sequel to the 2012 box office hit, Cold War, and stars returning cast members Aaron Kwok, Tony Leung, Charlie Young, Eddie Peng, Aarif Rahman and Ma Yili, joined by new cast members Chow Yun-fat, Janice Man, Tony Yang and Bibi Zhou. Cold War 2 was released on 8 July 2016 in 2D, 3D and IMAX 3D. It will be followed by two prequels, Cold War 1994 and Cold War 1995.
=== Anorexia === Interactions between MCH and chemokines/cytokines that lead to an overall decrease in MCH release and neuron excitability has been linked with infection-induced anorexia. Chemokines and cytokines often appear as the result of inflammation or infection, and they can then damage MCH neurons, which can lead to anorexia in an individual.
This causes the inhibition of pro-inflammatory and pruritogenic (itch-causing) cytokines that depend on JAK1 and JAK3, which include IL-2, IL-4, IL-6, IL-13, and IL-31 (TSLP, another pruritogenic cytokine that uses JAKs, has also been found to be inhibited). IL-31 is a key cytokine at the pruritogenic receptors at neurons near the skin, and also induces peripheral blood mononuclear cells and keratinocytes to release pro-inflammatory cytokines. Suppression of IL-4 and IL-13 causes a decrease of Th2-cell differentiation, which plays a role in atopic dermatitis. Oclacitinib's relatively little effect on JAK2 prevent it from suppressing hematopoiesis or the innate immune response. Oclacitinib inhibits JAK, not the pruritogenic cytokines themselves; studies in mice showed that suddenly stopping the medication caused an increase in itchiness caused by a rebound effect, where more cytokines were produced to overcome lack of response by JAK.
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.
The main proposal is modulation of neurotrophic factors such as brain-derived neurotrophic factor, supported largely by animal experiments. Receptor-level targets have not been firmly established. Most reviews describe the mechanism as only partially characterized.