neurotrophic signaling is one of those subjects where the details matter more than the headlines. This page pulls together the background, the mechanisms, and the practical points readers ask about most.
Last reviewed on 2026-08-01. Where a claim depends on a specific study, the study is described rather than over-claimed.
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。
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。
The C-terminal Pro-Gly-Pro extension is not incidental. Proline-rich tails are known to resist several common peptidases, and the published literature attributes the longer half-life of Semax, relative to unmodified ACTH fragments, to this feature. The modification also removes the melanocyte-stimulating and corticosteroidogenic activity that characterizes longer ACTH-derived sequences. Because the molecule is small and hydrophilic, it is typically formulated as an aqueous solution for intranasal or parenteral delivery. Acetylation or amidation at the termini appears in closely related research peptides and shifts the mass by a fixed increment.
Reported pharmacological work centers on neurotrophic signaling, including changes in BDNF and NGF expression in hippocampal tissue in animal models. Human data come largely from studies conducted in Russia, and how well those results generalize to other populations remains an open question. Regulatory status differs sharply by jurisdiction: Semax is a registered prescription medicine in Russia, while it holds no approved marketing status in the United States or the European Union. Outside such jurisdictions it is generally handled as a research chemical, which affects both documentation and quality expectations.
| Property | Value | Notes |
|---|---|---|
| 外观 | 白色至类白色粉末 | 常见于冻干制剂 |
| 溶解度 | 易溶于水 | 在极性溶剂中一般也可溶 |
| 建议储存温度 | -20 °C | 冻干粉，避光密封 |
| 常见分析手段 | 反相高效液相色谱 | 常与质谱联用 |
| 主要降解路径 | 水解与氧化 | 溶液状态更显著 |
Identity and purity of semax are established with reversed-phase high-performance liquid chromatography coupled to ultraviolet detection, usually at 214 nanometres. Mass spectrometry, most often electrospray ionisation in positive mode, confirms the molecular mass and reveals truncated sequences. Amino acid analysis and peptide mapping after enzymatic digestion provide additional structural confirmation. Laboratories typically report purity as the percentage area of the main peak, a figure that does not capture isomeric or oxidised variants unless the method resolves them.
The peptide is prone to several degradation pathways. Oxidation of the methionine residue produces a sulfoxide that elutes close to the parent peak in many chromatographic systems. Hydrolysis of peptide bonds and deamidation of susceptible residues in related sequences also reduce purity over time. Lyophilised material kept dry at minus twenty degrees Celsius and shielded from light is the most stable form commonly described in laboratory practice.
Material sold for laboratory use varies widely in stated purity and documentation. A certificate of analysis should list the analytical method, the column and detector used, and the observed purity value. Independent verification by an outside laboratory is the practical way to confirm identity when documentation is absent or internally inconsistent. Regulatory status differs by country, and a product legal in one jurisdiction may be unapproved or controlled in another.
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.
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.
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.
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.
== Animal feed == Copra meal is used as fodder for horses and cattle. Its high oil and protein levels are fattening for stock. The protein in copra meal has been heat treated and provides a source of high-quality protein for cattle, sheep and deer, because it does not break down in the rumen. Coconut oil can be extracted using either mechanical expellers or solvents (hexane). Mechanically expelled copra meal is of higher feeding value, because it contains typically 8–12% oil, whereas the solvent-extracted copra meal contains only 2–4% oil. Premium quality copra meal can also contain 20–22% crude protein, and < 20ppb aflatoxin. High-quality copra meal contains < 12% non-structural carbohydrate (NSC), which makes it well suited for feeding to horses that are prone to ulcers, insulin resistance, colic, tying up, and acidosis.
=== Phosphoenolpyruvate carboxykinase (PEPC-K) === Glyceroneogenesis can be regulated at two reaction pathways. First, it can be held at the decarboxylation of oxaloacetate to phosphoenolpyruvate. Secondly, the TCA cycle can affect glyceroneogenesis when the glutamate or substrates in the TCA cycle are being used as a precursor. Decarboxylation of oxaloacetate to phosphoenolpyruvate is catalyzed by PEPC-K, the essential enzyme which regulates glyceroneogenesis. Increases in PEPC-K levels or overexpression of the gene that codes for PEPC-K will increase glyceroneogenesis. Also, oxaloacetate can be decarboxylated to phosphoenolpyruvate when more PEPC-K can catalyze the reaction. Gene expression of PEPC-K can be suppressed by norepinephrine, glucocorticoids, and insulin. Norepinephrine is a neurotransmitter which decreases the activity of PEPC-K when the cell is in a cold environment. Glucocorticoids are steroid hormones involved in the reciprocal regulation of glyceroneogenesis in the liver and adipose tissues. Through a poorly-understood mechanism, they induce transcription of PEPC-K in the liver while decreasing transcription in adipose tissues. Insulin is a peptide hormone that causes cells to take in glucose. Through glyceroneogenesis, insulin down-regulates the expression of PEPC-K in both liver and adipose tissues.
=== Success === SOLAR was known for several others who enjoyed success, including: The Whispers, Dynasty, Lakeside, Midnight Star, Klymaxx, Calloway, Carrie Lucas, Collage and The Deele — which introduced singer/songwriter/producer Kenneth "Babyface" Edmonds and future music executive Antonio "L.A." Reid. Griffey had always believed in giving new talents the opportunity to create and develop their craft, and he was introduced to songwriters/producers Jimmy Jam and Terry Lewis by his A & R rep Dina R. Andrews (Dina Andrews Management Inc) who was the team's first manager, Reggie and Vincent Calloway, and Leon F. Sylvers III. The "SOLAR sound" was a collective effort, with artists working on each other's sessions and artists encouraged to be creative. Sylvers became SOLAR's house producer in 1978 and his signature basslines and productions helped mould the hit sound of SOLAR, which is funky, progressive dance music infused with soul and disco.
This allows other ants to detect what task group (e.g., foraging or nest maintenance) other colony members belong to. In ant species with queen castes, when the dominant queen stops producing a specific pheromone, workers begin to raise new queens in the colony. Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species.
Sources: en.wikipedia.org
==== MeSH D12.776.624.664.520 – oncogene proteins, viral ==== MeSH D12.776.624.664.520.045 – adenovirus early proteins MeSH D12.776.624.664.520.045.050 – adenovirus E1 proteins MeSH D12.776.624.664.520.045.050.100 – adenovirus E1A proteins MeSH D12.776.624.664.520.045.050.110 – adenovirus E1B proteins MeSH D12.776.624.664.520.045.060 – adenovirus e2 proteins MeSH D12.776.624.664.520.045.070 – adenovirus e3 proteins MeSH D12.776.624.664.520.045.080 – adenovirus e4 proteins MeSH D12.776.624.664.520.090 – antigens, polyomavirus transforming MeSH D12.776.624.664.520.420 – papillomavirus e7 proteins MeSH D12.776.624.664.520.750 – retroviridae proteins, oncogenic MeSH D12.776.624.664.520.750.320 – fusion proteins, gag-onc MeSH D12.776.624.664.520.750.320.700 – oncogene protein p65(gag-jun) MeSH D12.776.624.664.520.750.470 – gene products, rex MeSH D12.776.624.664.520.750.480 – gene products, tax MeSH D12.776.624.664.520.750.650 – oncogene protein gp140(v-fms) MeSH D12.776.624.664.520.750.710 – oncogene protein p21(ras) MeSH D12.776.624.664.520.750.750 – oncogene protein p55(v-myc) MeSH D12.776.624.664.520.750.760 – oncogene protein pp60(v-src) MeSH D12.776.624.664.520.750.788 – oncogene protein v-akt MeSH D12.776.624.664.520.750.817 – oncogene protein v-cbl MeSH D12.776.624.664.520.750.846 – oncogene protein v-crk MeSH D12.776.624.664.520.750.860 – oncogene protein v-maf MeSH D12.776.624.664.520.750.875 – oncogene proteins v-abl MeSH D12.776.624.664.520.750.882 – oncogene proteins v-erba MeSH D12.776.624.664.520.750.883 – oncogene proteins v-erbb MeSH D12.776.624.664.520.750.887 – oncogene proteins v-fos MeSH D12.776.624.664.520.750.900 – oncogene proteins v-mos MeSH D12.776.624.664.520.750.903 – oncogene proteins v-myb MeSH D12.776.624.664.520.750.920 – oncogene proteins v-raf MeSH D12.776.624.664.520.750.925 – oncogene proteins v-rel MeSH D12.776.624.664.520.750.935 – oncogene proteins v-sis
Some increases in fentanyl deaths do not involve prescription fentanyl but are related to illicitly made fentanyl that is being mixed with or sold as heroin. In 2017 the death rate increased by more than 100% with 368 overdose-related deaths in British Columbia between January and April 2017.
=== Förster resonance energy transfer biosensor === An engineered protein biosensor has been developed that can detect changes in O-GlcNAc levels using Förster resonance energy transfer. This sensor consists of four components linked together in the following order: cyan fluorescent protein (CFP), an O-GlcNAc binding domain (based on GafD, a lectin sensitive for terminal β-O-GlcNAc), a CKII peptide that is a known OGT substrate, and yellow fluorescent protein (YFP). Upon O-GlcNAcylation of the CKII peptide, the GafD domain binds the O-GlcNAc moiety, bringing the CFP and YFP domains into close proximity and generating a FRET signal. Generation of this signal is reversible and can be used to monitor O-GlcNAc dynamics in response to various treatments. This sensor may be genetically encoded and used in cells. Addition of a localization sequence allows for targeting of this O-GlcNAc sensor to the nucleus, cytoplasm, or plasma membrane.
Sources: en.wikipedia.org
These hazards in insects can be controlled in various ways. Allergic hazards can be labelled on the packaging to avoid consumption by susceptible consumers. Selective farming can be used to minimize chemical hazards, whereas microbial and parasitical hazards can be controlled by cooking processes.
This increase in calcium within the cell then activates a sodium-calcium exchanger (NCX). The sodium-calcium exchanger removes one Ca2+ from the cell and introduces three Na+ into the cell. This exchange further increases the membrane potential. Calcium later reenters the cell via SERCA and calcium channels located on the cell membrane. The increase in membrane potential produced by these mechanisms, activates T-type calcium channels and then L-type calcium channels (which open very slowly). These channels allow a flow of Ca2+ into the cell, making the membrane potential even more positive. Phase 0 This is the depolarization phase. When the membrane potential reaches the threshold potential (around -20 to -50 mV), the cell begins to rapidly depolarise (become more positive). This is mainly due to the flow of Ca2+ through L-type calcium channels, which are now fully open. During this stage, T-type calcium channels and HCN channels deactivate. Phase 3 This phase is the repolarization phase. This occurs due to the inactivation of L-type calcium channels (preventing the movement of Ca2+ into the cell) and the activation of potassium channels, which allows the flow of K+ out of the cell, making the membrane potential more negative.
A brief or only mildly elevated heart rate (heart rate taken while sitting down after recently walking across the room or getting up on the examination table) might be assumed to be due to anxiety or illness rather than exercise-induced inappropriate rapid heart rate due to an ATP shortage in the muscle cells. In the absence of severe symptoms (such as hepatomegaly, cardiomyopathy, hypoglycemia, lactic acidosis, myoglobinuria, rhabdomyolysis, acute compartment syndrome or renal failure), it is understandable that a disease would not be noticed by medical professionals for years, when at rest the patient appears completely normal. Depending on what enzyme is affected, a high-protein or low-fat diet may be recommended along with mild exercise. It is important for people with metabolic myopathies to consult with their doctors for a treatment plan in order to prevent acute muscle breakdowns while exercising that lead to the release of muscle proteins into the bloodstream that can cause kidney damage. A ketogenic diet has a remarkable effect on CNS-symptoms in PDH-deficiency and has also been tried in complex I deficiency. A ketogenic diet has demonstrated beneficial for McArdle disease (GSD-V) as ketones readily convert to acetyl CoA for oxidative phosphorylation, whereas free fatty acids take a few minutes to convert into acetyl CoA. As of 2022, another study on a ketogenic diet and McArdle disease (GSD-V) is underway.
== Function == The protein encoded by this gene is a member of the superfamily of ATP-binding cassette (ABC) transporters. ABC proteins transport various molecules across extra-and intra-cellular membranes. ABC genes are divided into seven distinct subfamilies (ABC1, MDR/TAP, MRP, ALD, OABP, GCN20, White). This full transporter is a member of the MRP subfamily which is involved in multi-drug resistance. This protein functions as a multispecific organic anion transporter, with oxidized glutathione, cysteinyl leukotrienes, and activated aflatoxin B1 as substrates. This protein also transports glucuronides and sulfate conjugates of steroid hormones and bile salts. Alternative splicing by exon deletion results in several splice variants but maintains the original open reading frame in all forms.
Sources: en.wikipedia.org
一般不建议常温长期保存。多数说明指向 -20 °C 冷冻避光。常温运输通常被视为短期可接受，但会加快降解风险。
公开资料对此没有统一答案。普遍建议现配现用，或冷藏并在数日内用完。含甲硫氨酸的序列更易氧化，放置时间越长风险越高。
反相高效液相色谱是最常用的手段，配合质谱确认分子量。氨基酸组成分析和肽图分析可补充序列层面的验证。
The sequence is Met-Glu-His-Phe-Pro-Gly-Pro, a seven-residue peptide. The first four residues correspond to the ACTH(4-10) fragment, and Pro-Gly-Pro is added at the C-terminus. N-acetylated versions also appear in the literature and differ in mass.