peptidase cleavage 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 2025-11-20. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
Lyophilised powder is normally kept at -20 °C in a desiccated container, with some suppliers recommending -80 °C for long-term archival storage. Repeated freeze-thaw cycles are the most common cause of avoidable loss, so aliquoting before freezing reduces variability between working sessions. Dissolved peptide is far less stable than the dry solid and is usually prepared fresh or held briefly at 4 °C. Aqueous solutions support both hydrolysis of the backbone and oxidation of the N-terminal methionine, and these two routes dominate degradation under ordinary laboratory conditions.
| Property | Value | Notes |
|---|---|---|
| Chemical class | Synthetic heptapeptide | ACTH(4-7) analogue |
| Sequence | Met-Glu-His-Phe-Pro-Gly-Pro | Free N terminus, unmodified side chains |
| Molecular weight | 813.9 Da | Free base; salt forms differ |
| Appearance | White to off-white powder | Lyophilised solid |
| Solubility | Freely soluble in water | Hydrophilic; polar solvents preferred |
The compound was developed in the 1980s at the Institute of Molecular Genetics in Moscow, where it emerged from research on short ACTH fragments and their effects on the central nervous system. Russian pharmaceutical listings describe it as a nootropic and neuroprotective agent, most often formulated as nasal drops. It is not a marketed medicine in the United States or the European Union, and no pharmacopoeial monograph covers it. Consequently, most published clinical experience with the substance originates from a small number of research centres, mainly in Russia and neighbouring countries.
Pharmacological accounts link semax to melanocortin signalling and to modulation of neurotrophic factor expression, particularly brain-derived neurotrophic factor and nerve growth factor. Much of this evidence comes from rodent studies using intranasal delivery, a route chosen because it allows peptides to reach the central nervous system with limited systemic exposure. Whether the same mechanisms operate in humans at comparable magnitude remains an open question. The precise receptor or receptors responsible for the reported behavioural and neuroprotective effects have not been conclusively identified.
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.
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.
Common degradation pathways include oxidation of the methionine side chain, hydrolysis of the peptide backbone, and aggregation under unfavourable pH or concentration. Stability studies typically monitor the main peak by chromatography and report total related substances as a percentage. Because no official monograph exists, acceptance criteria vary between laboratories, and reported purity values are not directly comparable across suppliers. Analysts therefore document the method, column, and detection wavelength alongside each result, and open questions remain about how much biological activity the oxidised forms retain.
The parent fragment ACTH(4-10) carries the sequence Met-Glu-His-Phe-Arg-Trp-Gly. Semax replaces the arginine and tryptophan positions with a proline-glycine-proline tail, giving Met-Glu-His-Phe-Pro-Gly-Pro. That change removes residues associated with adrenal stimulation, so the peptide does not drive cortisol release the way full ACTH does. This distinction shapes how the compound is grouped in the literature, where it sits with neuropeptides and peptide neuromodulators rather than with corticosteroids.
Regulatory status varies sharply by country. Semax is registered for medical use in Russia, where it appears in formularies as a nasal solution, and it also holds registration in a small number of neighbouring states. It has no approval from the United States Food and Drug Administration or the European Medicines Agency, and it is not a scheduled controlled substance in most jurisdictions. Elsewhere it circulates mainly as laboratory material, so purity documentation comes from suppliers rather than from a national pharmacopoeia.
Semax is a synthetic peptide created in the Soviet Union during the early 1980s by researchers working in Moscow. It was built from the short adrenocorticotropic hormone fragment known as ACTH(4-10), and the chain was then extended with three additional amino acids. The resulting molecule was named semax and entered clinical use in Russia in 1994. It is generally described as a nootropic and neuroprotective agent rather than as a hormone analogue.
The mechanisms attributed to semax are inferred from animal and cell studies rather than traced to one confirmed target. The most frequently cited pathway involves increased expression of brain-derived neurotrophic factor and nerve growth factor in hippocampal and cortical tissue. Some work points to engagement of melanocortin receptors, particularly MC4, which the parent ACTH fragment can activate. Effects on dopaminergic and serotonergic signalling have also been reported. No single account explains all observed results, and the relative weight of each pathway remains unsettled.
Published studies examine a fairly narrow set of endpoints. Rodent experiments commonly measure maze learning, infarct volume after induced ischemia, and tissue levels of neurotrophic factors. Clinical reports from Russian centres describe attention, memory and recovery scores in patients after stroke or transient ischemic attack. Most of those human studies are small and few have been repeated by independent groups. Outcome measures differ between studies, which limits direct comparison.
=== Other hydrazine derivative drugs === There are also cases where other hydrazine derivative drugs, such as the MAOI antidepressant iproniazid, are associated with liver damage. Phenelzine has been associated with abnormal liver tests. Toxic effects can develop from antibiotics, such as amoxicillin/clavulanic acid.
Other Marvel Comics adaptations have also had success with the Spider-Man and X-Men properties, while films based on Batman and Superman from DC Comics have generally performed well. Beyond the superhero genre, Star Wars, with four films, is the most represented franchise in the nominal earnings chart. Although the nominal earnings chart is dominated by films adapted from pre-existing properties and sequels, it is headed by Avatar, which is an original work. Animated family films have performed consistently well, with Disney films enjoying lucrative re-releases prior to the home-video era. Disney also enjoyed later success with films such as Frozen and its sequel, Zootopia and its sequel, and The Lion King (along with its computer-animated remake), as well as its Pixar division, of which Inside Out 2, Incredibles 2, and Toy Story 3, 4 and 5 have been the best performers. Beyond Disney and Pixar animation, China's Ne Zha 2 (the highest-grossing animated film), and the Despicable Me and Shrek series have met with the most success. While inflation has eroded the achievements of most films from the 1960s and 1970s, there are franchises originating from that period that are still active. Besides the Star Wars franchise, James Bond films are still being released periodically; both are among the highest-grossing franchises. Some of the older films that held the record of highest-grossing film still have respectable grosses by today's standards, but no longer compete numerically against today's top-earners in an era of much higher individual ticket prices.
== O == octreotide - odorant receptor - olfaction - olfactory receptor neuron - oligopeptide - oncogene - oncogene protein - oncogene proteins V-abl - oncogenic retroviridae protein - open reading frame - opioid receptor - opsin - optical isomerism - organ (anatomy) - organelle - organic chemistry - organic compound - organic nomenclature - organic reaction - organism - osmosis - osteocalcin - outer hair cell - outline of biochemical techniques - ovalbumin - oxidation - oxidation number - oxidation state - oxidative decarboxylation - oxidative phosphorylation - oxygen - oxytocin - oxytocin receptor
==== United Arab Emirates ==== The UAE takes an exceptionally strict line on medicines, with many common drugs, notably anything containing codeine being banned unless one has a notarized and authenticated doctor's prescription. Visitors breaking the rules, even inadvertently, have been deported or imprisoned. The US Embassy to the UAE maintains an unofficial list of what may not be imported.
Sources: en.wikipedia.org
The buffer capacity of a simple buffer solution is largest when pH = pKa. In acid–base extraction, the efficiency of extraction of a compound into an organic phase, such as an ether, can be optimised by adjusting the pH of the aqueous phase using an appropriate buffer. At the optimum pH, the concentration of the electrically neutral species is maximised; such a species is more soluble in organic solvents having a low dielectric constant than it is in water. This technique is used for the purification of weak acids and bases. A pH indicator is a weak acid or weak base that changes colour in the transition pH range, which is approximately pKa ± 1. The design of a universal indicator requires a mixture of indicators whose adjacent pKa values differ by about two, so that their transition pH ranges just overlap. In pharmacology, ionization of a compound alters its physical behaviour and macro properties such as solubility and lipophilicity, log p). For example, ionization of any compound will increase the solubility in water, but decrease the lipophilicity. This is exploited in drug development to increase the concentration of a compound in the blood by adjusting the pKa of an ionizable group. Knowledge of pKa values is important for the understanding of coordination complexes, which are formed by the interaction of a metal ion, Mm+, acting as a Lewis acid, with a ligand, L, acting as a Lewis base. However, the ligand may also undergo protonation reactions, so the formation of a complex in aqueous solution could be represented symbolically by the reaction
=== Casting === Bosworth was paid $500,000 to star as undercover cop Joe Huff, This was his first non-football role, and he trained extensively with acting coach Harold Guskin. Wichard, who was noted for his hyperbolic statements, claimed that some of the lessons lasted up to 20 hours. Michelle Johnson signed on to play Huff's wife, while Punky Brewster's Ami Foster was cast as his troubled younger sister, but creative changes led to both characters being cut during production. Lance Henriksen and Arabella Holzbog had appeared together shortly before in The Last Samurai. Henriksen had also co-starred with William Forsythe in the 1985 biker movie Savage Dawn. The lead actors trained with biker and stuntman Greg "Magic" Schwartz. Bosworth and Henriksen, both motorcycle enthusiasts, personally oversaw the customization of their bikes for the film. Henriksen's was painted by Jane Pollack, a member of the film's art department, who would later become his wife although the two did not connect on this shoot. Henriksen was unconvinced by the background players selected to portray his "Brotherhood", and personally toured Gulf Coast bike shops to recruit some that looked more legitimate. However, when a reporter mistakenly stated that Henriksen was a real-life member of the Bandidos MC gang, a rebuttal had to be quickly put out to avoid tensions with any of them.
=== Cognition and dementia === Colostrinin has possible efficacy in Alzheimer's disease and as a cognitive enhancer. A placebo-controlled clinical trial with Colostrinin in 106 people with Alzheimer's over 30 weeks was completed in 2002 and the results appeared to demonstrate efficacy in a significant proportion of patients treated. The results showed that approximately 40% of patients on Colostrinin were stabilized or improved after 15 weeks of therapy, based on an Analysis of Overall Response. 33% of patients continued to show stabilization or improvement after 30 weeks of treatment, although levels of benefit were slightly higher at the 15-week stage of the trial. The dosage regimen used for the trial was 100 micrograms of Colostrinin administered every second day for three weeks followed by a two-week period without Colostrinin. A 2010 study demonstrated that Colostrinin significantly relieved amyloid-beta (Aß)-induced cytotoxicity, alleviated the effect of Aß-induced cytotoxicity and caused a significant reduction in the elevated levels of the antioxidant enzyme SOD1. Another study showed that Colostrinin induces neurite outgrowth of pheochromocytoma cells and inhibits beta amyloid-induced apoptosis. There were also studies of the Colostrinin components and their possible effect on aggregation of amyloid beta (Abeta1-42). Results presented suggest that NP - Colostrinin component, can directly interact with amyloid beta, inhibit its aggregation and disrupt existing aggregates acting as a beta sheet breaker and reduce toxicity induced by aggregated forms of Abeta.
Bohr provided a derivation based on an atomic model, a result taken as substantial evidence in favor of his model. Bohr also used he model to describe the structure of the periodic table and aspects of chemical bonding. Together these results lead to Bohr's model being widely accepted by the end of 1915. Bohr's model was not perfect. It could only predict the spectral lines of hydrogen, not those of multielectron atoms. Worse still, it could not even account for all features of the hydrogen spectrum: as spectrographic technology improved, it was discovered that applying a magnetic field caused spectral lines to multiply in a way that Bohr's model couldn't explain. In 1916, Arnold Sommerfeld added elliptical orbits to the Bohr model to explain the extra emission lines, but this made the model very difficult to use, and it still couldn't explain more complex atoms.
Geneticists use diagrams and symbols to describe inheritance. A gene is represented by one or a few letters. Often a "+" symbol is used to mark the usual, non-mutant allele for a gene. In fertilization and breeding experiments (and especially when discussing Mendel's laws) the parents are referred to as the "P" generation and the offspring as the "F1" (first filial) generation. When the F1 offspring mate with each other, the offspring are called the "F2" (second filial) generation. One of the common diagrams used to predict the result of cross-breeding is the Punnett square. When studying human genetic diseases, geneticists often use pedigree charts to represent the inheritance of traits. These charts map the inheritance of a trait in a family tree.
Sources: en.wikipedia.org
=== 2016 === The "UHD Alliance", an industry consortium of content creators, distributors, and hardware manufacturers, announced Monday on January 11, 2016 during CES 2016 press conference its "Ultra HD Premium" specification, which defines resolution, bit depth, color gamut, high dynamic range (HDR) performance required for Ultra HD (UHDTV) content and displays to carry their Ultra HD Premium logo. On April 2, 2016, Ultra-high-definition television demo channel UHD1 broadcast the Le Corsaire ballet in Ultra HD live from the Vienna State Opera. The programme was produced by Astra satellite owner, SES in collaboration with European culture channel ARTE, and transmitted free-to-air, available to anyone with reception of the Astra 19.2°E satellites and an ultra HD screen equipped with an HEVC decoder. As of April 2016, The NPD Group reported that 6 million 4K UHD televisions had been sold. In May 2016, Modern Times Group, owner of the Viasat DTH platform announced the launch of Viasat Ultra HD, the first UHD channel for the Nordic region. The channel features selected live sport events especially produced in Ultra HD and launch in the autumn via the SES-5 satellite at 5°E. Viasat is also launching an Ultra HD set-top box from Samsung and a TV-module that enables existing UHD TVs to display the channel. Satellite operator, SES said that the launch of Viasat Ultra HD brings the number of UHD channels (including test channels and regional versions) carried on SES satellites to 24, or 46% of all UHD channels broadcast via satellite worldwide.
== External links == Gerngross TU, Slater SC (August 2000). "How green are green plastics?". Sci. Am. 283 (2): 37–41. Bibcode:2000SciAm.283b..36G. doi:10.1038/scientificamerican0800-36. PMID 10914397. Plastics from plants called costly (CNN) Tillman Gerngross Faculty Page at Dartmouth About Adimab LLC.
In January 2011, Parliament passed a law that enforces "strict quality control on universities and introduces tough rules for funding evaluation and peer review". Romania was ranked 49th in the Global Innovation Index in 2025. The nuclear physics facility of the EU's proposed Extreme Light Infrastructure (ELI) laser will be built in Romania. In early 2012, Romania launched its first satellite from the Centre Spatial Guyanais in French Guiana. Starting in December 2014, Romania became a co-owner of the International Space Station.
=== Toxin removal === Following diagnosis, rapid removal of excess leucine from the body reduces the impact of the disease on development. Some methods of toxin removal include Exchange transfusion, hemodialysis, or hemofiltration. Exchange transfusion is an option to consider because it decreases high BCAA levels without disrupting the plasma repeatedly, however after exchange the BCAA levels will increase with the tissue storage releasing BCAAs. Hemodialysis is a safe and effective way to reduce elevated BCAA levels while correcting electrolyte and acid-base imbalances in an infant. Hemodialysis can be started as soon as a diagnosis is made when it is combined with dietary feeds that maintain recommended calorie and amino acid intake.
Cancer that has spread to other parts of the body is usually treated also with hormone therapy, to deprive a tumour of sex hormones (androgens) that stimulate proliferation. This is often done through the use of GnRH analogues or agents (such as bicalutamide) that block the receptors that androgens act on; occasionally, surgical removal of the testes may be done instead. Cancer that does not respond to hormonal treatment, or that progresses after treatment, might be treated with chemotherapy such as docetaxel. Radiotherapy may also be used to help with pain associated with bony lesions. Sometimes, the decision may be made not to treat prostate cancer. If a cancer is small and localised, the decision may be made to monitor for cancer activity at intervals ("active surveillance") and defer treatment. If a person, because of frailty or other medical conditions or reasons, has a life expectancy less than ten years, then the impacts of treatment may outweigh any perceived benefits.
Sources: en.wikipedia.org
It is a synthetic seven-amino-acid peptide built from the ACTH(4-7) sequence plus a Pro-Gly-Pro tail. It belongs to the family of short ACTH fragments studied for nervous-system effects. Its backbone contains only standard amino acids.
It contains the 4-7 fragment of adrenocorticotropic hormone extended at the C terminus. That truncation removes the region associated with steroidogenic activity. The design intent was to keep neurotrophic properties while avoiding full hormonal effects.
No natural source of the intact heptapeptide is known. It is produced by solid-phase peptide synthesis. Some related ACTH fragments arise as hormone processing products, but the Pro-Gly-Pro extension is a designed addition rather than a natural sequence.
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.