RP-HPLC raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
This page was last updated on 2026-04-22 and is reviewed periodically as new material appears.
Semax is a synthetic heptapeptide developed in the Soviet Union during the 1980s by researchers at the Institute of Molecular Genetics in Moscow. It was designed as a truncated analog of adrenocorticotropic hormone, retaining only the fragment spanning residues four through ten. Investigators sought a peptide that would preserve the cognitive effects associated with ACTH while eliminating the hormonal stimulation of the adrenal cortex. The compound entered clinical use in Russia during the following decade.
Russian regulatory authorities approved the peptide for nasal administration, and it remains listed in the national pharmacopoeia under several trade names. Documented indications include acute ischemic stroke, transient ischemic attacks, traumatic brain injury, and certain ophthalmological and neurological conditions. Physicians also prescribe it for cognitive complaints in older patients, although the evidence base for that use is thinner. Outside Russia and a few neighboring states, the substance is not an approved medicine and is sold instead as a research chemical.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular class | Synthetic heptapeptide | Analog of an ACTH fragment |
| Amino acid length | Seven residues | Met-Glu-His-Phe-Pro-Gly-Pro |
| Origin | Moscow, 1980s | Institute of Molecular Genetics |
| Approved regions | Russia and some neighboring states | Not cleared in Western markets |
| Common trade names | Multiple national brands | Sold as a nasal formulation |
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.
Semax is a synthetic heptapeptide with the sequence Met-Glu-His-Phe-Pro-Gly-Pro. It is described in the literature as an analogue of the ACTH(4–10) fragment, a short N-terminal portion of adrenocorticotropic hormone that retains some neurotropic activity without the full hormonal effects of the parent peptide. The molecule carries a methionine residue at the N-terminus and two proline residues near the C-terminus, features that shape both its interactions with receptor systems and its chemical stability. The free peptide corresponds to the formula C37H51N9O10S and a molecular mass near 813.9 Da.
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.
Semax 是一种人工合成的七肽，氨基酸序列为 Met-Glu-His-Phe-Pro-Gly-Pro，单字母缩写记作 MEHFPGP。它被归类为促肾上腺皮质激素片段 ACTH(4-10) 的结构类似物，但并不天然存在于生物体内。母体片段 ACTH(4-10) 的序列为 Met-Glu-His-Phe-Arg-Trp-Gly，Semax 替换了中间两个残基，并在羧基端延长了 Pro-Gly-Pro 三肽。这种延长被普遍认为能提升分子对肽酶的耐受性。
该化合物于二十世纪八十年代在俄罗斯被开发，相关工作由俄罗斯科学院分子遗传学研究所的研究团队主导。开发目标并非复制 ACTH 的完整激素活性，而是寻找保留其神经作用方向、同时去除促肾上腺皮质激素释放效应的短肽片段。研究记录显示，这一方向促成了多个相关短肽的合成与筛选，而 Semax 是其中被研究最广泛的一个。当地文献常以 Семакс 这一名称指代它。
研究兴趣主要集中在神经营养因子相关的路径上，包括脑源性神经营养因子与神经生长因子的表达变化。部分实验报告称在特定条件下观察到这些因子的水平上升，但具体信号通路和剂量依赖关系仍未完全厘清。多数公开数据来自细胞模型和动物实验，人体对照研究数量有限。因此，该化合物的作用机制在文献中属于活跃讨论，而非已经确立的定论。
Once dissolved, the peptide is considerably less stable than the solid. Aqueous solutions are usually prepared at neutral to slightly acidic pH, filtered, and divided into single-use aliquots before freezing. Repeated freeze-thaw cycles are a common cause of avoidable loss and are best prevented by never refreezing a thawed aliquot. Adsorption to plastic and glass surfaces can lower the measured concentration of dilute solutions, particularly below roughly 0.1 mg/mL. Buffer choice, salt content, and container material all influence how much peptide remains detectable after storage.
Identity and purity are established with standard peptide methods. Reversed-phase HPLC with ultraviolet detection near 214 nm resolves the parent peak from deletion and truncation byproducts, and reports typically quote a main-peak percentage. Mass spectrometry by electrospray or MALDI-TOF confirms the expected molecular mass, while amino acid analysis or peptide mapping can verify composition when the sequence itself is in question. A certificate of analysis that pairs a chromatogram with a mass spectrum is more informative than a purity figure alone. Counter-ion content and residual solvents are separate specifications and are frequently omitted.
Semax is normally supplied as a lyophilized powder, and that form is the most stable. Suppliers commonly recommend storage at -20 °C in a desiccated container protected from light, with short-term handling at room temperature limited to weighing and transfer. Powder that has absorbed moisture degrades faster, so vials should be warmed to ambient temperature before opening to prevent condensation on the contents. Hygroscopic behavior is typical of short hydrophilic peptides, and humidity control matters more than temperature alone for long-term retention.
== Regulation == The regulation of the glyoxylate cycle involves carbon source availability, as it controls the transcriptional levels of key enzymes. Carbon catabolite repression is the main process that occurs in bacteria and fungi that regulates the transcriptional levels of the glyoxylate cycle, ensuring that the cycle is activated when glucose is not available. For instance, in Escherichia coli, the regulation of the isocitrate branch point takes place by regulating the transcription level of IclR and FadR, and through AceK, which is a bifunctional enzyme that acts as both a dehydrogenase kinase and a phosphatase. AceK is responsible for the regulation of isocitrate dehydrogenase and its switching roles in the citric acid cycle as well as the glyoxylate cycle. It determines whether the carbon atoms will be used in the glyoxylate cycle or the citric acid cycle. The phosphorylation, catalyzed by the AceK kinase function, of isocitrate dehydrogenase decreases its activity, and this phosphorylation can be reversed. In plants, the regulation of the glyoxylate cycle is achieved by regulating transcriptional levels during the seed germination process and through the mobilization of stored lipids . In bacteria, such as Mycobacterium tuberculosis, the glyoxylate cycle is up regulated especially when glucose is scarce and is needed during host infection. This regulation contributes to the growth and virulence of the pathogenic infection. Overall, these regulations allow for the conservation of carbon and activate the biosynthesis of key metabolites when carbon source is limited.
=== 6th Congress – CLP disbands (1993) === On January 31, 1993, at the Sixth Congress, the CLP voted unanimously to disband. This proposal was thoroughly discussed leading up to the 6th Congress. While many members initially had serious questions about the move to disband, they were eventually won over. One of the main arguments was that the CLP had failed to recruit new people and grow. Members believed that the organizational form of the CLP was not conducive to the further development of the revolutionary process. The "Call for the 6th Party Congress” (Rally, Comrades! Nov. 1992) raised the question, "What is the proper organizational form for revolutionaries in this quantitative stage of the revolution?” The Call states, "… this is not a time of preparation for the seizure of power. This is the moment to organize and politicize the social revolution. This is a time to struggle for the unity and political clarity of the millions who are in the diverse and daily struggle for jobs, health care and the other necessities of their lives.
Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked. Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species such as Strumigenys xenos are entirely parasitic and do not have workers, but instead, rely on the food gathered by their Strumigenys perplexa hosts. This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen may enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest. A conflict between the sexes of a species is seen in some species of ants with these reproducers apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in Wasmannia auropunctata, where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are clones of the father.
Sources: en.wikipedia.org
=== G04BE Drugs used in erectile dysfunction === G04BE01 Alprostadil G04BE02 Papaverine G04BE03 Sildenafil G04BE04 Yohimbin G04BE05 Phentolamine G04BE06 Moxisylyte G04BE07 Apomorphine G04BE08 Tadalafil G04BE09 Vardenafil G04BE10 Avanafil G04BE11 Udenafil G04BE30 Combinations G04BE52 Papaverine, combinations
In 2004, LSBC announced an agreement with Sigma-Aldritch under which LSB would produce recombinant aprotinin in plants of the tobacco family and Sigma-Aldrich would commercially distribute LSBC's recombinant product to its customers in the R&D, cell culture and manufacturing markets. As of October 2012 SIgma still has the protein in stock. Meristem Therapeutics – Lipase, lactoferrin, plasma proteins, collagen, antibodies (IgA, IgM), allergens and protease inhibitors in tobacco. Liquidated in 2008. Novoplant GmgH – therapeutic proteins in tobacco and feed peas. Conducted field trials in US of feed peas for pigs that produced anti-bacterial antibodies. Former CSO is now with another company; appears that Novoplant is out of business. Monsanto Company – abandoned development of pharmaceutical producing corn PPL Therapeutics – Alpha 1-antitrypsin for cystic fibrosis and emphysema in sheep milk. This is the company that created Dolly the Sheep, the first cloned animal. Went bankrupt in 2004. Assets were acquired by Pharming and an investment group including University of Pittsburgh Medical Center. SemBioSys – insulin in safflower. In May 2012, SemBioSys terminated its operations.
=== Hoyle–Wickramasinghe model of panspermia === Throughout his career, Wickramasinghe, along with his collaborator Fred Hoyle, has advanced the panspermia hypothesis, that proposes that life on Earth is, at least in part, of extraterrestrial origin. The Hoyle–Wickramasinghe model of panspermia include the assumptions that dormant viruses and desiccated DNA and RNA can survive unprotected in space; that small bodies such as asteroids and comets can protect the "seeds of life", including DNA and RNA, living, fossilized, or dormant life, cellular or non-cellular; and that the collisions of asteroids, comets, and moons have the potential to spread these "seeds of life" throughout an individual star system and then onward to others. The most contentious issue around the Hoyle–Wickramasinghe model of the panspermia hypothesis is the corollary of their first two propositions that viruses and bacteria continue to enter the Earth's atmosphere from space, and are hence responsible for many major epidemics throughout history. Towards the end of their collaboration, Wickramasinghe and Hoyle hypothesised that abiogenesis occurred close to the Galactic Center before panspermia carried life throughout the Milky Way, and stated a belief that such a process could occur in many galaxies throughout the Universe.
Sources: en.wikipedia.org
Meanwhile, life cycle reversal, in which polyps are formed directly from medusae without the involvement of sexual reproduction process, was observed in both Hydrozoa (Turritopsis dohrnii and Laodicea undulata) and Scyphozoa (Aurelia sp.1). Anthozoa have no medusa stage at all and the polyps are responsible for sexual reproduction. Spawning is generally driven by environmental factors such as changes in the water temperature, and their release is triggered by lighting conditions such as sunrise, sunset or the phase of the moon. Many species of Cnidaria may spawn simultaneously in the same location, so that there are too many ova and sperm for predators to eat more than a tiny percentage — one famous example is the Great Barrier Reef, where at least 110 corals and a few non-cnidarian invertebrates produce enough gametes to turn the water cloudy. These mass spawnings may produce hybrids, some of which can settle and form polyps, but it is not known how long these can survive. In some species the ova release chemicals that attract sperm of the same species. The fertilized eggs develop into larvae by dividing until there are enough cells to form a hollow sphere (blastula) and then a depression forms at one end (gastrulation) and eventually becomes the digestive cavity. However, in cnidarians the depression forms at the end further from the yolk (at the animal pole), while in bilaterians it forms at the other end (vegetal pole). The larvae, called planulae, swim or crawl by means of cilia.
In Syria, an Israeli airstrike on a copper plant near Aleppo killed 16 members of Iran-backed militias. Hezbollah said that it fired drones at the IDF's headquarters in the Galilee. It also claimed a drone attack in Metula. The IDF confirmed that two drones crashed in northern Israel while a third was intercepted. Acting Minister of Foreign Affairs of Iran made his first overseas visit as foreign minister to Lebanon, during which he confirmed that the Iranian government was engaged in negotiations with the United States hosted by Oman. Forest fires in northern Israel were erupted the entire week which reportedly resulted in 2,500 acres of land burnt and the hospitalization of six Israeli soldiers and five civilians due to smoke inhalation. On 11 June, an Israeli strike on a command and control center in Jwaya killed senior Hezbollah commander Taleb Abdallah and three other militants. The next day, in response to Taleb's killing, Hezbollah launched a barrage of about 90 rockets into Israel targeting an IDF factory, military headquarters in Ein Zeitim and Ami'ad, and an air surveillance station in Meron. It later fired another 70 at the Mount Meron area, and then ten more at Zar'it, bringing the total number of launches to 170. It increased to 215 by the late afternoon. On 13 June, Hezbollah fired 150 rockets and 30 UAVs at 15 targets in northern Israel and the Golan Heights. Amos Hochstein, a senior advisor to US President Joe Biden, arrived in Israel on 17 June to attempt to de-escalate tensions between Israel and Lebanese militias.
Alexandra C. Newton is a Canadian and American biochemist. She is a Distinguished Professor of pharmacology at the University of California, San Diego. Newton runs a multidisciplinary Protein kinase C and Cell signaling biochemistry and cell biology research group in the School of Medicine, investigating molecular mechanisms of signal transduction in the Phospholipase C (PLC) and Phosphoinositide 3-kinase (PI3 kinase, or PI3-K) signaling pathways. She has been continuously funded by the US National Institutes of Health since 1988. Newton was born in Cape Town, South Africa, and was schooled in Vancouver, Athens, and Aix-en-Provence. She graduated in 1980 from the Simon Fraser University in Canada, where she was awarded a 1st-class honours degree in biochemistry and French literature. She received her PhD in chemistry in 1986 from Stanford University, working with Wray H. Huestis on a thesis examining band 3, a red cell membrane protein.
The NAD-I riboswitch (also called the nadA motif) was identified in species of the bacterial phylum Acidobacteriota, where it typically resides upstream of nadA genes encoding quinolate synthase, an enzyme in the de novo NAD⁺ biosynthesis pathway. Unusually, despite regulating genes relevant to NAD⁺ metabolism, neither binding domain of the NAD⁺-I riboswitch's dual-aptamer architecture has been shown to specifically recognize the nicotinamide portion of the coenzyme; instead, the RNA robustly binds the adenosine 5′-diphosphate (ADP) moiety of NAD⁺.
Sources: en.wikipedia.org
It originated at the Institute of Molecular Genetics in Moscow during the 1980s. The work was carried out by a Russian research group that specialized in peptide neuropharmacology.
It is registered as a medicine in Russia and has been used clinically there for decades. No regulatory agency in Western Europe or North America has approved it for any indication.
Semax corresponds to the four-to-ten fragment of adrenocorticotropic hormone. Because it omits the first three residues, it lacks the adrenal-stimulating action of the full hormone.
Reversed-phase high-performance liquid chromatography is the standard method, with detection in the ultraviolet range. Peak area percentage yields a purity figure for the main component. Mass spectrometry is normally run alongside to confirm molecular identity.