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 2026-02-16 and is reviewed periodically as new material appears.
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.
Development of the compound took place in the Soviet Union during the 1980s, largely through peptide research groups affiliated with the Shemyakin-Ovchinnikov Institute and Moscow State University. Investigators screened fragments of adrenocorticotropic hormone for activity on the central nervous system while attempting to separate cognitive effects from hormonal ones. The shortened sequence was selected because it retained behavioral activity in animal models without stimulating corticosteroid release. Early publications described the molecule as an ACTH(4-10) analog.
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 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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C37H51N9O10S | Seven-residue peptide |
| Molecular mass | 813.9 Da | Monoisotopic value |
| Appearance | White to off-white powder | Lyophilized form |
| Solubility | Freely soluble in water | Also soluble in saline and polar solvents |
| Storage (dry) | -20 °C or lower | Desiccated, protected from light |
CH3C(O)CO−2 → "CH3CO−" + CO2 This irreversible reaction is catalyzed by the pyruvate dehydrogenase complex. It consists of three enzymes: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2), dihydrolipoamide dehydrogenase (E3), six cofactors: thiamine pyrophosphate (TPP), lipoamide, coenzyme A (CoA), flavin adenine dinucleotide (FAD), magnesium ion, and one co-substrate: nicotinamide adenine dinucleotide (NAD+). Pyruvate converts the thiazole ring of TPP to its hydroxyethyl derivative, concomitant with decarboxylation. With the catalysis of E2, TPP-CH(OH)CH3 reacts with the S-S bond of lipoamide to produce thioester bond (acetyl dihydrolipoamide. The acetyl reacts with CoA-SH to give Acetyl-CoA and dihydrolipoamide. The latter is oxidized to lipoamide (with S-S bond) by FAD.
The first automated insulin delivery system was known as the Biostator. Currently available AID systems fall into three broad classes based on their capabilities. The first systems released can only halt insulin delivery (predictive low glucose suspend) in response to already low or predicted low glucose. Hybrid Closed Loop systems can modulate delivery both up and down, although users still initiate insulin doses (boluses) for meals and typically "announce" or enter meal information. Fully Closed Loops require no manual insulin delivery actions or announcement for meals. A step forward from threshold suspend systems, predictive low glucose suspend (PLGS) systems use a mathematical model to extrapolate predicted future blood sugar levels based on recent past readings from a CGM. This allows the system to reduce or halt insulin delivery prior to a predicted hypoglycemic event.
== Gameplay == Counter-Strike is an objective-based, multiplayer tactical first-person shooter. Two opposing teams—the Terrorists and the Counter-Terrorists—compete in game modes to complete objectives, such as securing a location to plant or defuse a bomb and rescuing or guarding hostages. At the end of each round, players are rewarded based on their individual performance with in-game currency to spend on more powerful weapons in subsequent rounds. Winning rounds results in more money than losing and completing objectives such as killing enemy players gives cash bonuses. Uncooperative actions, such as killing teammates, result in a penalty.
Lactose is often used as the primary filler (main ingredient) in most prescription and non-prescription solid pill form medications, though product labeling seldom mentions the presence of 'lactose' or 'milk', and neither do product monograms provided to pharmacists, and most pharmacists are unaware of the very wide scale yet common use of lactose in such medications until they contact the supplier or manufacturer for verification.
Sources: en.wikipedia.org
"The sloths of the West Indies: a systematic and phylogenetic review". In Woods, C.A.; Sergile, F.E. (eds.). Biogeography of the West Indies: Patterns and Perspectives. Boca Raton, London, New York, and Washington, D.C.: CRC Press. pp. 201–235. doi:10.1201/9781420039481-14. ISBN 978-0-8493-2001-9.
Ronald E. Blaylock, Managing Partner of GenNx360 Capital Partners Albert Bourla, CEO of Pfizer Mortimer J. Buckley, former CEO of The Vanguard Group Sue Desmond-Hellmann, former CEO of The Bill and Melinda Gates Foundation Joseph J. Echevarria, former CEO of Deloitte LLP Scott Gottlieb, former Commissioner of the FDA Helen Hobbs, Professor at the University of Texas Southwestern Medical Center Susan Hockfield, 16th President of the Massachusetts Institute of Technology Dan Littman, professor of Molecular Immunology at New York University Shantanu Narayen, CEO of Adobe Suzanne Nora Johnson, former Vice Chairman of Goldman Sachs James Quincey, CEO of The Coca-Cola Company James C. Smith, former CEO of Thomson Reuters Cyrus Taraporevala, former president and CEO of State Street Global Advisor
=== Transmission of signal === The presence of hormone or multiple hormones enables a response in the receptor, which begins a cascade of signaling. The hormone receptor interacts with different molecules to induce a variety of changes, such as an increase or decrease of nutrient sources, growth, and other metabolic functions. These signaling pathways are complex mechanisms mediated by feedback loops where different signals activate and inhibit other signals. If a signaling pathway ends with the increase in production of a nutrient, that nutrient is then a signal back to the receptor that acts as a competitive inhibitor to prevent further production. Signaling pathways regulate cells through activating or inactivating gene expression, transport of metabolites, and controlling enzymatic activity to manage growth and functions of metabolism.
With the discovery of protactinium, most of the decay chains of uranium had been mapped. When Hahn returned to his work after the war, he looked back over his 1914 results, and considered some anomalies that had been dismissed or overlooked. He dissolved uranium salts in a hydrofluoric acid solution with tantalic acid. First the tantalum in the ore was precipitated, then the protactinium. In addition to the uranium X1 (thorium-234) and uranium X2 (protactinium-234), Hahn detected traces of a radioactive substance with a half-life of between 6 and 7 hours. There was one isotope known to have a half-life of 6.2 hours, mesothorium II (actinium-228). This was not in any probable decay chain, but it could have been contamination, as the KWIC had experimented with it. Hahn and Meitner demonstrated in 1919 that when actinium is treated with hydrofluoric acid, it remains in the insoluble residue. Since mesothorium II was an isotope of actinium, the substance was not mesothorium II; it was protactinium. Hahn was now confident enough he had found something that he named his new isotope "uranium Z". In February 1921, he published the first report on his discovery. Hahn determined that uranium Z had a half-life of around 6.7 hours (with a two per cent margin of error) and that when uranium X1 decayed, it became uranium X2 about 99.75 per cent of the time, and uranium Z around 0.25 per cent of the time.
== Biological synthesis == Hyaluronic acid is synthesized by a class of integral membrane proteins called hyaluronan synthases, of which vertebrates have three types: HAS1, HAS2, and HAS3. These enzymes lengthen hyaluronan by repeatedly adding D-glucuronic acid and N-acetyl-D-glucosamine to the nascent polysaccharide as it is extruded via ABC-transporter through the cell membrane into the extracellular space. The term fasciacyte was coined to describe fibroblast-like cells that synthesize HA. Hyaluronic acid synthesis has been shown to be inhibited by 4-methylumbelliferone (hymecromone), a 7-hydroxy-4-methylcoumarin derivative. This selective inhibition (without inhibiting other glycosaminoglycans) may prove useful in preventing metastasis of malignant tumor cells. There is feedback inhibition of hyaluronan synthesis by low-molecular-weight hyaluronan (<500 kDa) at high concentrations, but there is stimulation by high-molecular-weight hyaluronan (>500 kDa) when tested in cultured human synovial fibroblasts. Bacillus subtilis recently has been genetically modified to culture a proprietary formula to yield hyaluronans, in a patented process producing human-grade product.
Sources: en.wikipedia.org
where CL is total body clearance (L/h), BSA is total body surface area (m2), AAG and ALB represent alpha1 acid glycoprotein and albumin plasma concentrations (g/L) respectively, and AGE is the patients age (years). HEP12 represents a measure of hepatic dysfunction, affecting clearance of docetaxel. This final model accounted for a modest proportion of patients and identified most of the patients varying from the model (population median of CL = 35.6 L/h) as having hepatic dysfunction, indicating hepatic function as the most unpredictable factor with regards to clearance variability. Patients with significant hepatic dysfunction had an approximately 30% decrease in clearance of docetaxel and were also at a higher risk of toxicity poisoning from docetaxel treatment. Clearance has been shown from population pharmacokinetic studies to decrease significantly with age, increased alpha1 acid glycoprotein and albumin concentrations and decreased body surface area. Renal impairment is unlikely to affect metabolism or excretion of docetaxel as renal excretion contributes less than 5% of elimination. Limited data is available for docetaxel use in children with dosage between 55 and 75 mg/m2. Two paediatric studies have taken place that show a mean clearance of 33 L/h/m2 and concentration-time profiles best fitted by a two-compartmental model of distribution and elimination. Mean distribution half-life was 0.09 hours and mean elimination half-life was 1.4 hours in paediatric studies.
(CH3)2CHC(O)CH3 + HCN + NH3 → (CH3)2CHC(CN)(NH2)CH3 + H2O The initial reaction product of 3-methyl-2butanone with sodium cyanide and ammonia is resolved by application of L-tartaric acid. In contrast, asymmetric Strecker reactions require no resolving agent. By replacing ammonia with (S)-alpha-phenylethylamine as chiral auxiliary the ultimate reaction product was chiral alanine.
=== Other Heseltine comments === Heseltine criticised the Coalition's policy on Europe, but he did support the tightening of immigration laws. He also supported George Osborne's Budget measures in 2013 and Iain Duncan Smith's welfare reforms, but showed concerns over the legalisation of same-sex marriage. In June 2013, he voted against Lord Dear's wrecking amendment, thus ratifying the same-sex marriage act.
=== Ornamental uses === Rhodium finds use in jewelry and for decorations. It is electroplated on white gold and platinum to give it a reflective white surface at time of sale, after which the thin layer wears away with use. This is known as rhodium flashing in the jewelry business. It may also be used in coating sterling silver to protect against tarnish (silver sulfide, Ag2S, produced from atmospheric hydrogen sulfide, H2S). Solid (pure) rhodium jewelry is very rare, more because of the difficulty of fabrication (high melting point and poor malleability) than because of the high price. The high cost ensures that rhodium is typically applied as an electroplate. Rhodium has also been used for honors or to signify elite status, when more commonly used metals such as silver, gold or platinum were deemed insufficient. In 1979 the Guinness Book of World Records gave Paul McCartney a rhodium-plated disc for being history's all-time best-selling songwriter and recording artist and in 2008, Barack Obama gave his wife a rhodium ring.
Sources: en.wikipedia.org
It is a synthetic peptide of seven amino acids. Its backbone corresponds to a fragment of adrenocorticotropic hormone extended at the carboxyl end. The material is distributed as a lyophilized solid for laboratory use.
The extension was introduced to slow enzymatic breakdown of the peptide in biological systems. Natural ACTH fragments are degraded rapidly by peptidases. Adding the tripeptide was intended to extend the window during which the molecule remains intact.
Most published work consists of animal experiments conducted in a small number of laboratories. Human data are limited in number and size. Whether the observed effects translate into reliable clinical benefit is still unresolved.
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.