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 2025-09-06 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. Its chain combines the first seven residues of corticotropin with a C-terminal proline-glycine-proline extension, a modification intended to slow enzymatic breakdown. The free peptide has a molecular mass near 813.9 daltons. It belongs to the class of ACTH-derived fragments studied for central nervous system activity rather than for adrenal steroid stimulation. This structural relationship to a natural hormone fragment is the usual starting point for describing the compound in the literature.
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.
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.
Dissolution is normally performed in water, phosphate-buffered saline, or normal saline, since the peptide is freely soluble in aqueous media and is rarely handled with strong organic solvents. Solution pH should be kept near neutral, because extreme acidity or alkalinity accelerates backbone hydrolysis and encourages oxidation of the methionine side chain. Once dissolved, the material is less stable than the dry powder and is commonly divided into single-use portions and frozen. Buffers containing primary amines, such as Tris, are often avoided because of possible side reactions.
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.
| Property | Value | Notes |
|---|---|---|
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Heptapeptide; ACTH(4-10) analog extended at C-terminus |
| Molecular mass | ~813.9 Da | Free peptide, unmodified |
| Appearance | White to off-white powder | Typical lyophilized solid |
| Solubility | Soluble in water and saline | Also soluble in common aqueous buffers |
| Storage (solid) | -20 °C, desiccated | Protect from moisture and repeated thawing |
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.
Published studies are dominated by animal models of stroke, ischemia, and cognitive impairment, with a smaller number of human trials conducted in Russia. Many of the human reports are small, single-center, and published in Russian-language journals, which limits independent scrutiny. Outcome measures vary between studies and often rely on clinician-rated scales rather than objective biomarkers. Systematic reviews have noted the methodological weaknesses and called for larger, preregistered trials before firm conclusions can be drawn.
Claims about enhanced focus, memory, or mood in healthy people rest mostly on anecdotal reports and community discussion rather than on controlled data. It remains unclear whether any cognitive benefit observed in patients recovering from brain injury would extend to uninjured users. Dose-response relationships, long-term safety, and interactions with other drugs are not well characterized in the peer-reviewed literature. Questions about optimal route of administration and treatment duration likewise remain open.
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.
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 Red Savina pepper is a cultivar of the habanero chili (Capsicum chinense Jacquin), which has been selectively bred to produce spicier, heavier, and larger fruit, ultimately more potent than its derivative. Frank Garcia of GNS Spices, in Walnut, California, is credited as the developer of the Red Savina, but the exact methodology that Garcia used to select the hottest breeding strains is not publicly known.
== Activity == Klebsazolicin is active against Gram-negative bacteria closely related to Klebsiella, such as Escherichia coli, Klebsiella pneumoniae, and Yersinia pseudotuberculosis. KLB inhibits protein synthesis on the prokaryotic ribosome by binding to and blocking peptide exit tunnel and thus preventing the passage of the nascent peptide. The activity of KlpE export pump encoded in KLB biosynthetic gene cluster confers self-resistance of the producing bacterium to the action of the antibiotic.
In the morning of 8 October, Hezbollah fired rockets and shells at the Shebaa Farms region in support of Hamas's attack onto Israel; in response, the Israel Defense Forces (IDF) fired artillery shells and a drone into southern Lebanon. Two Lebanese children were reportedly injured by broken glass. The next day, Israel exchanged a series of airstrikes on southern Lebanon near the towns of Marwahin, Ayta ash Shab and Dhayra in the Bint Jbeil district. This was after numerous Palestinian militants infiltrated the Israeli border, which Hezbollah denied involvement with. The Palestinian Islamic Jihad militia claimed responsibility for the armed infiltration. The IDF killed at least two perpetrators (likely Palestinians), while a third returned to Lebanon. A Hezbollah media source announced three of Hezbollah's members died in the IDF retaliation. Hezbollah fired rockets and artillery in retaliation. During the clashes, two Israeli soldiers and Lt. Col Alim Abdallah, Deputy Commander of the IDF's 300th Brigade, were killed and another three were wounded. On 11 October, Hezbollah fired anti-tank missiles at an IDF position and claimed to have produced casualties. In response, the IDF shelled the area where the attack was launched. The Lebanese-Italian hospital in Tyre admitted three injured civilians. The IDF ordered residents of northern Israel to seek shelter following reports of drones being launched from southern Lebanon. A Patriot missile was launched to intercept a suspicious projectile, after which the IDF found that the object in question was not a drone.
Leucoanthocyanidin reductase (EC 1.17.1.3) (LAR, aka leucocyanidin reductase or LCR) is an enzyme that catalyzes several related chemical reduction steps in flavonoid biosynthesis. For example, it converts leucocyanidin to catechin.
Sources: en.wikipedia.org
The operating principle of CCC equipment requires a column consisting of a tube coiled around a bobbin. The bobbin is rotated in a double-axis gyratory motion (a cardioid), which causes a variable g-force to act on the column during each rotation. This motion causes the column to see one partitioning step per revolution and components of the sample separate in the column due to their partitioning coefficient between the two immiscible liquid phases. "High-performance" countercurrent chromatography (HPCCC) works in much the same way as HSCCC. A seven-year research and development process produced HPCCC instruments that generated 240 g's, compared to the 80 g's of the HSCCC machines. This increase in g-force and larger bore of the column has enabled a ten-fold increase in throughput, due to improved mobile phase flow rates and a higher stationary phase retention. Countercurrent chromatography is a preparative liquid chromatography technique, however with the advent of the higher-g HPCCC instruments it is now possible to operate instruments with sample loadings as low as a few milligrams, whereas in the past hundreds of milligrams had been necessary. Major application areas for this technique include natural product purification and drug development.
Bioprinting can also be used for cultured meat. In 2021, a steak-like cultured meat, composed of three types of bovine cell fibers was produced. The Wagyu-like beef has a structure similar to original meat. This technology provides an alternative to natural meat harvesting methods if the livestock industry is plagued by disease. In addition, it provides a possible solution to reducing the environmental impact of the livestock industry. Bioremediation uses microorganisms or in recent times, materials of biological origin, such as enzymes, biocomposites, biopolymers, or nanoparticles, to biochemically degrade contaminants into harmless substances, making it an environmentally friendly and cost-effective alternative; 3D bioprinting facilitates the fabrication of functional structures using these materials that enhance bioremediation processes leading to a significant interest in the application of 3D bioprinted constructs in improving bioremediation.
=== Related drugs === Although described as SNRIs, duloxetine (Cymbalta), venlafaxine (Effexor), and desvenlafaxine (Pristiq) are in fact relatively selective as serotonin reuptake inhibitors (SRIs). They are about at least 10-fold selective for inhibition of serotonin reuptake over norepinephrine reuptake. The selectivity ratios are approximately 1:30 for venlafaxine, 1:10 for duloxetine, and 1:14 for desvenlafaxine. At low doses, these SNRIs act mostly as SSRIs; only at higher doses do they also prominently inhibit norepinephrine reuptake. Milnacipran (Ixel, Savella) and its stereoisomer levomilnacipran (Fetzima) are the only widely marketed SNRIs that inhibit serotonin and norepinephrine to similar degrees, both with ratios close to 1:1. Vilazodone (Viibryd) and vortioxetine (Trintellix) are SRIs that also act as modulators of serotonin receptors and are described as serotonin modulators and stimulators (SMS). Vilazodone is a 5-HT1A receptor partial agonist while vortioxetine is a 5-HT1A receptor agonist and 5-HT3 and 5-HT7 receptor antagonist. Litoxetine (SL 81–0385) and lubazodone (YM-992, YM-35995) are similar drugs that were never marketed. They are SRIs and litoxetine is also a 5-HT3 receptor antagonist while lubazodone is also a 5-HT2A receptor antagonist.
==== Canada ==== 5-MAPB is not an explicitly listed controlled substance in the Controlled Drugs and Substances Act in Canada. However, it is an implicitly controlled substance in this country under the act's phenethylamine and amphetamine catch-all clauses, which bans amphetamines as well as phenethylamine benzofurans.
==== Native Hawaiian or other Pacific Islander ==== The obesity rate for Native Hawaiian or other Pacific Islander adults (over 30 BMI) in the US in 2015 was 33.4%. No breakdown by sex was given for Native Hawaiian or other Pacific Islander adults in the CDC figures.
Sources: en.wikipedia.org
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.
Its sequence corresponds to the 4-10 region of corticotropin extended by three residues. This fragment lacks the region responsible for adrenal steroid release, so it is explored for neural rather than hormonal effects. The relationship explains the compound's classification among ACTH-derived peptides.
It holds approval in Russia for several neurological indications as a nasal spray or drop formulation. Regulatory agencies in the United States and the European Union have not approved it. Products sold elsewhere are generally labeled for research use only.
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.