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 2026-03-25 and is reviewed periodically as new material appears.
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.
Identity and purity are confirmed with reversed-phase high-performance liquid chromatography, typically monitored at 214 nanometres where the peptide bond absorbs. Mass spectrometry, either electrospray or MALDI-TOF, verifies molecular mass against the theoretical value and detects truncation or adduct formation. Amino acid analysis and peptide mapping provide additional confirmation when required. The most frequently reported impurities are deletion sequences from incomplete coupling, methionine sulfoxide from oxidation, and dimeric species formed through non-covalent aggregation. Impurity profiles depend strongly on the synthesis and purification route chosen by the producer.
Published research has focused mainly on neurological and cognitive endpoints in animal models, with proposed mechanisms involving brain-derived neurotrophic factor and related signalling pathways. A substantial share of the human data originates from a limited number of research groups, and independent replication in other countries remains sparse. Regulatory status reflects that distribution: the peptide is registered as a medicine in Russia and appears in some neighbouring markets, while elsewhere it is handled as a research chemical without approved therapeutic labelling. Questions about dose-response relationships, long-term effects, and comparability across studies are still open.
| 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。
当时的短肽研究普遍关注能否穿越血脑屏障、在低剂量下产生中枢效应，Semax 属于这一路线。鼻内给药是其主要使用方式，俄语文献报道的适应症涵盖缺血性卒中、短暂性脑缺血发作、认知功能减退以及视神经病变。这些研究大多发表在当地期刊上，样本规模与终点设置同西方试验惯例存在差异，国际同行对其临床证据的强度看法不一。
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.
== Structure and properties == The molecular weight of lactate racemase differs in the various organisms in which it has been found, ranging from 25,000 to 82,400 g/mol. The structure of the enzyme from L. plantarum was solved by Jian Hu and Robert P. Hausinger of Michigan State University and co-workers there and elsewhere. The protein contains a previously unknown covalently-linked nickel-pincer nucleotide (NPN) cofactor (pyridinium 3-thioamide-5-thiocarboxylic acid mononucleotide), where the nickel atom is bound to C4 of the pyridinium ring and two sulfur atoms. This cofactor participates in a proton-coupled hydride-transfer mechanism. There have been a number of recent studies on NPN cofactor synthesis by the LarB, LarE, and LarC proteins. LarB is a carboxylase/hydrolase of nicotinamide adenine dinucleotide (NAD), providing pyridinium-3,5-dicarboxylic acid mononucleotide and adenosine monophosphate (AMP). LarE is an ATP-dependent sulfur transferase that converts the two substrate carboxyl groups into thioacids by sacrificing the sulfur atoms of a cysteine residue in the protein. Finally, LarC inserts nickel into the organic ligand by a CTP-dependent process to complete synthesis of the NPN cofactor.
== Structure == The 3D structure of human serum albumin has been determined by X-ray crystallography to a resolution of 2.5 ångströms (250 pm). Albumin is a 65–70kDa protein. Albumin comprises three homologous domains that assemble to form a heart-shaped protein. Each domain is a product of two subdomains that possess common structural motifs. The principal regions of ligand binding to human serum albumin are located in hydrophobic cavities in subdomains IIA and IIIA, which exhibit similar chemistry. Structurally, the serum albumins are similar, each domain containing five or six internal disulfide bonds.
Following a 15-month ATP-commissioned investigation conducted by The Lake Forest Group (a third-party consultant working with the ATP's outside legal counsel, Smith Hulsey & Busey), the ATP announced in late January 2023 that they would not punish Zverev due to insufficient evidence to substantiate the allegations.
M791 armor-piercing discarding sabot with tracer The APDS-T penetrates lightly armored vehicles, self-propelled artillery, and aerial targets such as helicopters and various slow-moving, fixed-wing aircraft. Reported velocity of 1,345 m/sec. M792 high explosive incendiary with tracer and self destruct The HEI-T can destroy unarmored vehicles and helicopters and suppress anti-tank missile positions and enemy squads out to a maximum effective range of 2,200 meters. Uses the M758 fuse, reported velocity of 1,100 m/sec. M793 target practice with tracer The TP-T cartridge is a fixed-type, percussion-primed training round that matches the high explosive incendiary with tracer (HEI-T M792) round ballistically. The TP-T's tracer is visible out to 2,000 meters, however, the round has a maximum effective range (accuracy-limited) of 1,600 meters. Reported velocity of 1,100 m/sec. M910 target practice discarding sabot with tracer The TPDS-T replicates the flight pattern of the M791 armor piercing discarding sabot with tracer (APDS-T) round. The TPDS-T allows units to realistically practice sabot engagements. Reported velocity of 1,515 m/sec. MK210 high explosive incendiary with tracer Used by the U.S. Navy in their Mk38 naval weapon system. M919 armor-piercing, fin-stabilized discarding sabot with tracer. The APFSDS-T round penetrates lightly armored vehicles, self-propelled artillery, and aerial targets, which include helicopters and slow-moving fixed-wing aircraft. The dart is made of depleted uranium.
Sources: en.wikipedia.org
=== Streptomyces === Daptomycin is another naturally occurring lipidated peptide, produced by the Gram positive bacterium Streptomyces roseoporous. The structure of Daptomycin consists of a decanoyl lipid chain attached to a partially cyclised peptide head group. It has very potent antimicrobial properties and is used as an antibiotic to treat life-threatening conditions caused by Gram positive bacteria including MRSA (methicillin-resistant Staphylococcus aureus) and vancomycin resistant Enterococci. As with the Bacillus subtilis lipidated peptides, the permeation of the cell membrane is what gives it its properties, and the mechanism of action with daptomycin is thought to involve the insertion of the decanoyl chain into the bacterial membrane to cause disruption. This then causes a serious depolarization resulting in the inhibition of various synthesis processes including those of DNA, protein and RNA, leading to apoptosis.
A new King Crimson formation was announced in 2007: Fripp, Belew, Levin, Mastelotto, and a new second drummer, Gavin Harrison of Porcupine Tree. In August 2008, after a period of rehearsals, the five completed the band's 40th Anniversary Tour. The setlists featured no new material, drawing instead from the existing Larks' Tongues-era/Discipline-era/Double Trio/Double Duo repertoire. Additional shows were planned for 2009, but were cancelled due to scheduling clashes with Belew. King Crimson began another hiatus after the 40th Anniversary Tour. Belew continued to lobby for reviving the band, and discussed it with Fripp several times in 2009 and 2010. Among Belew's suggestions was a temporary reunion of the 1980s line-up for a thirtieth anniversary tour: an idea declined by both Fripp and Bruford, the latter commenting "I would be highly unlikely to try to recreate the same thing, a mission I fear destined to failure." In December 2010, Fripp wrote that the King Crimson "switch" had been set to "off" since October 2008, citing several reasons for this decision. In August 2012, Fripp announced his planned retirement from the music industry, leaving the future of King Crimson uncertain.
December 13: Constitution of 22 Frimaire Year VIII (establishing the Consulate) grants citizenship only to men over 21, born and residing in France, and registered in their commune's civic registry, effectively excluding women. 1800
The meat of a lamb is taken from the animal between one month and one year old, with a carcass weight of between 5.5 and 30 kg (12 and 66 lb). This meat generally is more tender than that from older sheep and appears more often on tables in some Western countries. Hogget and mutton have a stronger flavour than lamb because they contain a higher concentration of species-characteristic fatty acids and are preferred by some. Mutton and hogget also tend to be tougher than lamb (because of connective tissue maturation) and are therefore better suited to casserole-style cooking, as in Lancashire hotpot, for example. Lamb is often sorted into three kinds of meat: forequarter, loin, and hindquarter. The forequarter includes the neck, shoulder, front legs, and the ribs up to the shoulder blade. The hindquarter includes the rear legs and hip. The loin includes the ribs between the two. Lamb chops are cut from the rib, loin, and shoulder areas. The rib chops include a rib bone; the loin chops include only a chine bone. Shoulder chops are usually considered inferior to loin chops; both kinds of chops are usually grilled. Breast of lamb (baby chops) can be cooked in an oven. Leg of lamb is a whole leg; saddle of lamb is the two loins with the hip. Leg and saddle are usually roasted, though the leg is sometimes boiled. Forequarter meat of sheep, as of other mammals, includes more connective tissue than some other cuts, and, if not from a young lamb, is best cooked slowly using either a moist method, such as braising or stewing, or by slow roasting or American barbecuing.
When a person swims under the water, water pressure is felt acting on the person's eardrums. The deeper that person swims, the greater the pressure. The pressure felt is due to the weight of the water above the person. As someone swims deeper, there is more water above the person and therefore greater pressure. The pressure a liquid exerts depends on its depth. Liquid pressure also depends on the density of the liquid. If someone was submerged in a liquid more dense than water, the pressure would be correspondingly greater. Thus, we can say that the depth, density and liquid pressure are directly proportionate. The pressure in a liquid of uniform density is represented by the following formula:
Sources: en.wikipedia.org
== Founding fathers of the United States == John Jay (King's 1764), president of the Continental Congress; first chief justice of the United States; author of five of The Federalist papers; first secretary of foreign affairs under the Articles of Confederation; architect of Jay Treaty with Great Britain Robert Livingston (King's 1764), a writer of the Declaration of Independence as part of the Committee of Five; first U.S. secretary of foreign affairs; negotiator of the Louisiana Purchase Egbert Benson (King's 1765), delegate to the Continental Congress, U.S. representative, first New York State attorney general, chief justice of the New York Supreme Court Gouverneur Morris (King's 1768), represented Pennsylvania in the Continental Congress; authored much of the United States Constitution; U.S. ambassador to France; United States senator from New York Alexander Hamilton* (King's 1776), American Revolutionary War officer, aide-de-camp to George Washington; most prolific writer of The Federalist Papers; first United States secretary of the treasury, portrayed on the ten-dollar bill; founder of the Bank of New York
Phlebotomy is the process of making a puncture in a vein, usually in the arm or hand, with a cannula for the purpose of drawing blood. The procedure itself is known as a venipuncture, which is also used for intravenous therapy. A person who performs a phlebotomy is called a phlebotomist, although most doctors, nurses, and other technicians can also carry out a phlebotomy. In contrast, phlebectomy is the removal of a vein. Phlebotomies that are carried out in the treatment of some blood disorders are known as therapeutic phlebotomies. The average volume of whole blood drawn in a therapeutic phlebotomy to an adult is 1 unit (450–500 ml) weekly to once every several months, as needed.
== Physiologic effects == BNP decreases sodium reabsorption in the distal convoluted tubule (interaction with NCC) and cortical collecting duct of the nephron via guanosine 3',5'-cyclic monophosphate (cGMP) dependent phosphorylation of ENaC.
=== Cancer diagnosis === Although pathologic examination is the current standard method for molecular characterization in testing for the presence of biomarkers in tumors, these single-sample analyses fail to account for the diverse genomic nature of tumors. Considering the invasive nature, psychological stress, and the financial burden resulting from repeated tumor biopsies in patients, biomarkers that could be judged through minimally invasive procedures, such as blood draws, constitute an opportunity for progression in precision medicine. Liquid biopsy is an option that is becoming increasingly popular as an alternative to solid tumor biopsy. This is simply a blood draw that contains circulating tumor cells (CTCs) which are shed into the bloodstream from solid tumors. Patients with metastatic cancer are more likely to have detectable CTCs in the bloodstream but CTCs also exist in patients with localized diseases. It has been found that the number of CTCs present in the bloodstream of patients with metastatic prostate and colorectal cancer is prognostic of the overall survival of tumors. CTCs also have been demonstrated to inform prognosis in earlier stages of the disease.
Masson's trichrome is a three-colour staining procedure used in histology. The recipes emerged from Claude L. Pierre Masson's (1880–1959) original formulation have different specific applications, but all are suited for distinguishing cells from surrounding connective tissue. Most recipes produce red keratin and muscle fibers, blue or green collagen and bone, light red or pink cytoplasm, and dark brown to black cell nuclei. The trichrome is applied by immersion of the fixated sample into Weigert's iron hematoxylin, and then three different solutions, labeled A, B, and C:
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.
Reversed-phase HPLC gives the main purity figure, most often with UV detection near 214 nanometres. Mass spectrometry then confirms the molecular mass. Together the two methods distinguish a correct sequence from a closely related impurity.