This is a working overview of 肽纯度, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-09 and is reviewed periodically as new material appears.
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.
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.
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.
Proposed mechanisms center on neurotrophic signaling rather than on classical melanocortin receptor activation. Rodent experiments have reported shifts in the expression of brain-derived neurotrophic factor and nerve growth factor after administration, together with changes in the associated receptor systems. Several authors argue that the peptide acts largely through its degradation products and their interaction with peptidergic pathways, but this remains a hypothesis rather than a settled finding. No single molecular target has been identified in a way that the field broadly accepts.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Contains one methionine sulfur atom |
| Molecular mass | Approximately 814 Da | Consistent with a seven-residue peptide |
| Appearance | White to off-white powder | Typical lyophilized form |
| Solubility | Freely soluble in water | Also soluble in dimethyl sulfoxide |
| Typical storage | -20 °C, desiccated | Limits methionine oxidation |
各国监管态度分化明显。俄罗斯按处方药管理，部分东欧国家留有使用记录；欧盟与美国未批准其作为药物上市，市面流通品通常标注为研究用化学品。身份差异意味着标示含量、纯度与无菌性缺少统一核查。体育领域还牵涉反兴奋剂名录，跨境携带则受目的地药品法规约束。
Semax 是人工设计的七肽，序列为 Met-Glu-His-Phe-Pro-Gly-Pro，骨架取自促肾上腺皮质激素片段 ACTH(4-10)。它于二十世纪八十年代在苏联的分子遗传学研究机构内合成。设计目标是保留该片段与注意力和记忆相关的活性，同时剔除促皮质激素释放等内分泌作用。此后俄罗斯将其登记为药品并进入临床使用。
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。
Regulatory status differs sharply between jurisdictions. In Russia the peptide is registered as a prescription nasal preparation, while agencies such as the United States Food and Drug Administration have not approved it for any indication. Products sold elsewhere are typically labeled for laboratory research only, and such labels shift responsibility for safe handling to the purchaser. Because the same name covers pharmaceutical-grade nasal drops and bulk research powder, identity and purity documentation becomes the main practical concern when comparing sources.
Semax is a synthetic seven-amino-acid peptide whose sequence extends the ACTH(4-10) fragment with a C-terminal proline-glycine-proline tripeptide. The commonly cited sequence is Met-Glu-His-Phe-Pro-Gly-Pro, giving a molecular formula near C37H51N9O10S and a molecular weight close to 813.9 g/mol. It belongs to the broader class of synthetic ACTH fragments studied for central nervous system effects rather than for adrenal steroid stimulation. In practice the material appears as a lyophilized white powder for laboratory work or as a dilute saline solution in clinical settings.
Development is attributed to researchers at the Institute of Molecular Genetics in Moscow during the early 1980s, building on earlier Soviet work with ACTH fragments. Russian regulatory approval followed for intranasal use, and the compound has remained commercially available there for decades. Most published human data originate from Russian and, later, some Eastern European clinical reports, which are not always accessible in English translation. Outside that region the material is generally handled as a research chemical rather than a licensed medicine.
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.
Practical handling follows from those properties. Bulk material is best divided into single-use portions soon after receipt, because each thaw exposes the whole container to moisture and temperature cycling. Vials should be allowed to reach room temperature before opening to prevent condensation on the powder. Low-binding plasticware reduces loss of dilute solutions, and sterile filtration is used when a preparation must remain free of microbial growth. Records of batch number, reconstitution date and storage history are what allow a later analytical result to be interpreted meaningfully.
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.
Bio Products Laboratory Limited (BPL) is a company involved in the manufacture of human blood plasma products, located in Elstree, Hertfordshire, England. It is run as a commercial business and supplies plasma derived products to the National Health Service in the UK as well as to markets in over 45 countries. BPL was a state owned organization and it was part of the U.K. National Health Service for most of its existence. On 1 September 2022, Permira and the Marcucci family acquired BPL and announced that their operations will be merged with another company acquired by the duo, Kedrion.
==== Neonatal hypoglycemia ==== Low blood sugar may occur in healthy neonates aged less than 48 hours who have not eaten for a few hours. During the 48-hour neonatal period, the neonate adjusts glucagon and epinephrine levels following birth, which may trigger transient hypoglycemia. In children who are aged greater than 48 hours, serum glucose on average ranges from 70 to 100 mg/dL (3.9–5.5 mmol/L), similar to adults, with hypoglycemia being far less common.
Breadfruit – used similarly as jackfruit in savory dishes Coconut burger – made from sapal, the coconut pulp by-products of traditional coconut milk extraction in Filipino cuisine Eggplant – semitropical/tropical plant with a highly textured flesh Grapefruit – during the course of the Special Period economic crisis Cubans prepared steaks made out of breaded and fried grapefruit rind known as "bistec de toronja". Jackfruit – a fruit whose flesh has a similar texture to pulled pork when cooked
Ensuring data privacy and security: Farmers have concerns about who can access their data. Their concerns extend to government use of data; German farmers reported a "lack of data security and excessive transparency vis-à-vis the public authorities." Scholars have issued repeated calls for policymakers to address agricultural data privacy and security. Address data ownership: According to the European Parliamentary Research Service, "it is clear that the farmer owns the data generated on his fields." The German Agricultural Society and others concur. However, in practice, farmers lack control over data about themselves and their farms. Besides establishing regulations to boost stakeholder confidence, policymakers can harness digital agriculture for the provision of public goods. First, the United Nations' Global Open Data for Agriculture and Nutrition (GODAN) calls for open access to agricultural data as a basic right. Rather than stakeholders operating in "data silos," where no one shares information for fear of competition, open data sources (when appropriately anonymized) can foster collaboration and innovation. Open-sourced data can rebalance the power asymmetry between farmers and large agribusinesses who collect data. Second, governments can finance research and development of digital agriculture.
Sources: en.wikipedia.org
Archaeol's biosynthesis proceeds by a multistep process mediated by several enzymes. In simplified terms, glycerol 1-phosphate is etherified to two geranylgeranyl substituents contributed by geranylgeranyl pyrophosphate. The double bonds are reduced by nicotinamide and flavins. The phosphate group is subject to modification. Archaea utilize biosynthetic pathways of isoprenoids that is distinct compared to bacteria and eukarya. The C5 precursors to the geranylgeranyl chains are isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are produced by modified mevalonic acid pathway.
circular DNA Any DNA molecule, single-stranded or double-stranded, which forms a continuous closed loop without ends; e.g. bacterial chromosomes, mitochondrial and plastid DNA, as well as many other varieties of extrachromosomal DNA, including plasmids and some viral DNA. Contrast linear DNA.
== Difference between xeno-, exo-, and astro-biology == "Astro" means "star" and "exo" means "outside". Both exo- and astrobiology deal with the search for naturally evolved life in the Universe, mostly on other planets in the circumstellar habitable zone. (These are also occasionally referred to as xenobiology.) Whereas astrobiologists are concerned with the detection and analysis of life elsewhere in the Universe, xenobiology attempts to design forms of life with a different biochemistry or different genetic code than on planet Earth.
=== COVID-19 === In 2020, the monoclonal antibody therapies bamlanivimab/etesevimab and casirivimab/imdevimab were given emergency use authorizations by the US Food and Drug Administration to reduce the number of hospitalizations, emergency room visits, and deaths because of COVID-19. In September 2021, the Biden administration purchased US$2.9 billion worth of Regeneron monoclonal antibodies at $2,100 per dose to curb the shortage. As of December 2021, in vitro neutralization tests indicate monoclonal antibody therapies (with the exception of sotrovimab and tixagevimab/cilgavimab) were not likely to be active against the Omicron variant. Over 2021–22, two Cochrane reviews found insufficient evidence for using neutralizing monoclonal antibodies to treat COVID-19 infections. The reviews applied only to people who were unvaccinated against COVID‐19, and only to the COVID-19 variants existing during the studies, not to newer variants, such as Omicron. In March 2024, pemivibart, a monoclonal antibody drug, received an emergency use authorization from the US FDA for use as pre-exposure prophylaxis to protect certain moderately to severely immunocompromised individuals against COVID-19.
=== Hepatic Function === The liver stores excess glucose in the form of glycogen after a meal, in response to insulin. Between meals (or during fasting), the liver is stimulated to break down this glycogen to release glucose (glycogenolysis) and also synthesizes new glucose (gluconeogenesis); this glucose is released into the bloodstream to maintain normal function of the brain and other organs that burn glucose for energy. Glycogenolysis and gluconeogenesis are stimulated by hormones such as glucagon that activate the cyclic AMP pathway in liver hepatocytes, and this cAMP promotes activation of metabolic enzymes leading to glucose production and release; asprosin appears to utilize this same system of control. Asprosin was reported to stimulate glucose release from hepatocytes, and plasma levels of asprosin in obese high-fat-fed mice have been reported to nearly double. However, in a study in 2019, a pharma replication group reported their inability to replicate these two key observations using recombinant asprosin, suggesting that issues with reagent purity may have been responsible for the effect observed in the initial asprosin study. Nevertheless, a third group reported in 2019 that they had identified the liver receptor for asprosin, OR4M1, an olfactory receptor family GPCR, and showed that plasma asprosin levels increased with fasting and with diet-induced obesity, and confirmed asprosin's effect on stimulation of hepatic glucose production, replicating all facets of the original study.
Sources: en.wikipedia.org
It is registered as a pharmaceutical product in Russia, where it is typically supplied as a nasal solution. In most other countries it is not an approved drug and is traded as a research chemical instead. Approval status depends entirely on the jurisdiction involved.
Most published work uses intranasal administration, matching the route of the registered Russian formulation. Some animal experiments use intravenous or intraperitoneal injection. The route matters because the intact peptide is cleared rapidly from blood, so exposure differs between methods.
A purity value describes the share of the powder accounted for by the target peptide, usually by high-performance liquid chromatography. It does not confirm that the sequence is correct, which requires mass spectrometry or amino acid analysis. Purity and identity are separate checks.
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.