The short version of Methionine oxidation fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2025-08-25 and is reviewed periodically as new material appears.
Routine characterization relies on reversed-phase high-performance liquid chromatography to establish purity and on mass spectrometry to confirm molecular identity. Electrospray ionization and matrix-assisted laser desorption ionization are both used for mass verification. Amino acid analysis and peptide mapping can detect sequence errors. Common impurities include truncated sequences, methionine sulfoxide formed by oxidation, and deamidated products. Chromatograms are usually recorded near 214 nm, where the peptide backbone absorbs, and purity is reported as the percentage area of the principal peak.
Verification of a supplied batch generally combines a certificate of analysis with independent testing, because certificates are self-reported documents. A typical package includes a chromatographic trace, a mass spectrum, and a stated water or counter-ion content. Batch-to-batch consistency matters more than a single purity figure when results are compared across experiments. No single mandatory standard governs research-grade peptide release, so laboratories are expected to define their own acceptance criteria. Residual trifluoroacetate from purification is a frequently overlooked counter-ion.
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.
Clinical evidence consists largely of small trials with modest sample sizes, often without independent replication. Reported endpoints include cognitive scores, recovery after stroke, and visual function, but study designs vary widely and few trials meet contemporary reporting standards. Systematic reviewers have noted a high risk of bias in several of these reports. No large multicenter trial conducted outside Russia has been published. The compound is therefore best described as investigational in most jurisdictions, with its clinical role still unresolved.
| Property | Value | Notes |
|---|---|---|
| Typical purity | 95% or higher | By reversed-phase HPLC area |
| Identity method | Electrospray mass spectrometry | Confirms molecular mass |
| Purity method | Reversed-phase HPLC | Detection near 214 nm |
| Primary degradation | Methionine oxidation | Sulfoxide product, +16 Da |
| Solution storage | 2-8 °C, short term | Aliquot to avoid freeze-thaw |
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.
Identity and purity of Semax are established mainly by reversed-phase high-performance liquid chromatography coupled with mass spectrometry. The chromatographic trace gives a purity estimate as a percentage of total peak area, while electrospray or matrix-assisted laser desorption ionization confirms the molecular mass against the calculated value. Amino acid analysis and sequence-specific fragmentation provide further confirmation when a supplier's chain of custody is unclear. Vendors frequently quote a purity figure without stating the detection wavelength or the integration method, which limits how far one number can be compared with another.
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.
=== Hormonal control === Lactiferous duct development occurs in females in response to circulating hormones. First development is frequently seen during pre- and postnatal stages, and later during puberty. Estrogen promotes branching differentiation, whereas in males testosterone inhibits it. A mature duct tree reaching the limit of the fat pad of the mammary gland comes into being by bifurcation of duct terminal end buds (TEB), secondary branches sprouting from primary ducts and proper duct lumen formation. These processes are tightly modulated by components of mammary epithelial ECM interacting with systemic hormones and local secreting factors. However, for each mechanism the epithelial cells' "niche" can be delicately unique with different membrane receptor profiles and basement membrane thickness from specific branching area to area, so as to regulate cell growth or differentiation sub-locally. Important players include beta-1 integrin, epidermal growth factor receptor (EGFR), laminin-1/5, collagen-IV, matrix metalloproteinase (MMPs), heparan sulfate proteoglycans, and others. Elevated circulating level of growth hormone and estrogen get to multipotent cap cells on TEB tips through a thin, leaky layer of basement membrane. These hormones promote specific gene expression. Hence cap cells can differentiate into myoepithelial and luminal (duct) epithelial cells, and the increased amount of activated MMPs can degrade surrounding ECM helping duct buds to reach further in the fat pads.
=== United States === In the US, there can be stigma that hinders people with sickle cell disease from receiving necessary care; one element of this is attributed to racism as the majority of people with sickle cell disease are black. Due to this, in 1970, the Black Panther Party (also known as the Black Panther Party for Self Defense) opened dozens of free clinics across the U.S. where free Sickle Cell Disease tests were offered. Over the course of the 1970s, thousands of people, largely African-Americans, received testing at one of these clinics. In September 2017, the US Social Security Administration issued a policy interpretation ruling providing background information on sickle cell disease and a description of how Social Security evaluates the disease during its adjudication process for disability claims.
Pempel (1966), professor of political science and former director of the Institute of Asian Studies at the University of California, Berkeley Roger Sanjek (1966), professor of anthropology at Queens College, City University of New York David Weissbrodt (1966), legal scholar at the University of Minnesota Law School known for drafting the Minnesota Protocol Jay Winter (1966), World War I specialist at Yale University Paul Gewirtz (1967), constitutional law scholar Karl Klare (1967), critical legal studies theorist Norman Friedman (1967), author and naval analyst Mott T. Greene (1967), historian of science, professor at University of Puget Sound Reza Sheikholeslami (1967), Soudavar Professor of Persian Studies at Wadham College, Oxford Jeremy Siegel (1967), professor of the Wharton School of the University of Pennsylvania Terrell Carver (1968), political theorist; professor at the University of Bristol Samuel R. Gross (1968), professor at the University of Michigan Law School; editor of the National Registry of Exonerations project Charles Lindholm (1968), University Professor of Anthropology at Boston University Alfred W. McCoy (1968), historian of Southeast Asia; professor at the University of Wisconsin–Madison Lawrence Susskind (1968), urban planner and mediator; professor at the Massachusetts Institute of Technology Jerry Avorn (1969), professor at the Harvard Medical School William Boone Bonvillian (1969), scholar of innovation technology policy, former director of MIT's Washington, D.C.
Laboratory LOINC: It covers laboratory tests, microbiology tests (including antibiotic susceptibilities) Clinical LOINC: It covers a variety of non-lab concepts (ECG concepts, cardiac echo, obstetric ultrasound). Within clinical LOINC, there are also sup-parts for Clinical documents: concepts for various types of clinical reports (e.g., discharge summary, well-child visit note) Survey instruments: concepts for standardized surveys (e.g., Glasgow Coma Score, PHQ-9 depression scale)
=== Journals === ACS Chemical Biology – The new Chemical Biology journal from the American Chemical Society. Bioorganic & Medicinal Chemistry – The Tetrahedron Journal for Research at the Interface of Chemistry and Biology ChemBioChem – A European Journal of Chemical Biology Chemical Biology – A point of access to chemical biology news and research from across RSC Publishing Cell Chemical Biology – An interdisciplinary journal that publishes papers of exceptional interest in all areas at the interface between chemistry and biology. chembiol.com Journal of Chemical Biology – A new journal publishing novel work and reviews at the interface between biology and the physical sciences, published by Springer. link Journal of the Royal Society Interface – A cross-disciplinary publication promoting research at the interface between the physical and life sciences Molecular BioSystems – Chemical biology journal with a particular focus on the interface between chemistry and the -omic sciences and systems biology. Nature Chemical Biology – A monthly multidisciplinary journal providing an international forum for the timely publication of significant new research at the interface between chemistry and biology. Wiley Encyclopedia of Chemical Biology link
Sources: en.wikipedia.org
Though no Tyrannosaurus scleral ring has been found, Kenneth Carpenter estimated its size based on that of Gorgosaurus. The inferred scleral ring for the Stan specimen is ~7 cm (2.8 in) in diameter with an internal aperture diameter of ~3.5 cm (1.4 in). Based on eye proportions in living reptiles, this implies a pupil diameter of about 2.5 cm (0.98 in), an iris diameter about that of the scleral ring, and an eyeball diameter of 11–12 cm (4.3–4.7 in). Carpenter also estimated an eyeball depth of ~7.7–9.6 cm (3.0–3.8 in). Based on these calculations, the f-number for Stan's eye is 3–3.8; since diurnal animals have f-numbers of 2.1 or higher, this would indicate that Tyrannosaurus had poor low-light vision and hunted during the day. Tyrannosaurus had very large olfactory bulbs and olfactory nerves relative to their brain size, the organs responsible for a heightened sense of smell. This suggests that the sense of smell was highly developed, and implies that tyrannosaurs could detect carcasses by scent alone across great distances. The sense of smell in tyrannosaurs may have been comparable to modern vultures, which use scent to track carcasses for scavenging. Research on the olfactory bulbs has shown that T. rex had the most highly developed sense of smell of 21 sampled non-avian dinosaur species.
Clathurellinae was split into three families: Borsoniidae (also including species from Turridae), Mitromorphidae and Clathurellidae (all previously lumped under the Turridae). Conorbiinae was raised to the rank of family Conorbidae, consisting of three genera: Artemidiconus da Motta, 1991, Benthofascis Iredale, 1936, and Conorbis Swainson, 1840. Mangeliinae and Oenopotinae were combined and raised to the rank of family Mangeliidae, which had previously been lumped in the Turridae). Raphitominae was raised to the rank of family Raphitomidae (also previously lumped in the Turridae). The classification by Bouchet et al. (2011) was based on mitochondrial DNA and nuclear DNA testing, and built on the prior work by J.K. Tucker & M.J. Tenorio (2009), but did not include fossil taxa. Molecular phylogeny, particularly with the advent of nuclear DNA testing in addition to the mDNA testing (testing in the Conidae initially began by Christopher Meyer and Alan Kohn), is continuing on the Conidae.
==== Phase I–II ==== A phase I safety trial began on 18 June 2020. On 4 September 2020, data on 76 participants in a phase I–II trial were published, indicating preliminary evidence of safety and an immune response. The results were challenged by international vaccine scientists as being incomplete, suspicious, and unreliable when identical data were reported for many of the trial participants, but the authors responded that there was a small sample size of nine, and the measured results of titration could only take discrete values (800, 1600, 3200, 6400). Coupled with the observation that values tended to reach a plateau after three to four weeks, they contend that it is not unlikely that several participants would show identical results for days 21 to 28.
On 5 October 2018, Singapore carried out three executions of drug traffickers - Zainudin bin Mohamed, Abdul Wahid Bin Ismail, and Mohsen Bin Na’im, it led to the Asian Forum for Human Rights and Development (FORUM-ASIA) and 28 civil society organizations in Asia showing condemnation over the triple hangings, and these groups the death sentence was a grave violation of the right to life, which was "the most fundamental and essential human right for other rights to be realized". They also argued that the executions of Zainudin, Abdul Wahid and Mohsen did not serve any purpose for the island-state and its citizens in terms of fulfilling the ends of justice. In March 2022, when Singapore dismissed the final appeal of Malaysian death row prisoner Nagaenthran K. Dharmalingam and later authorized the execution of Singaporean drug convict Abdul Kahar Othman, which was its first execution during the COVID-19 pandemic, there were 400 Singaporeans, including rights activists Jolovan Wham, Kirsten Han and Kokila Annamalai, who took part in a protest against the government's use of the death penalty at Hong Lim Park. With regards to Abdul Kahar's execution, the European Union (EU) condemned it and stated that capital punishment is a cruel and inhumane punishment, which not only failed to deter crime but also defied both humanity's dignity and integrity. Two days prior to Nagaenthran's execution (which took place on 27 April 2022), a candlelight vigil was held on his behalf.
Many ancient cultures practiced various forms of heliotherapy, including people of Ancient Greece, Ancient Egypt, and Ancient Rome. The Inca, Assyrian and early Germanic peoples also worshipped the sun as a health bringing deity. Indian medical literature dating to 1500 BCE describes a treatment combining herbs with natural sunlight to treat non-pigmented skin areas. Buddhist literature from about 200 CE and 10th-century Chinese documents make similar references. The Faroese physician Niels Finsen is believed to be the father of modern phototherapy. He developed the first artificial light source for this purpose. Finsen used short wavelength light to treat lupus vulgaris, a skin infection caused by Mycobacterium tuberculosis. He thought that the beneficial effect was due to ultraviolet light killing the bacteria, but recent studies showed that his lens and filter system did not allow such short wavelengths to pass through, leading instead to the conclusion that light of approximately 400 nanometers generated reactive oxygen that would kill the bacteria. Finsen also used red light to treat smallpox lesions. He received the Nobel Prize in Physiology or Medicine in 1903. Scientific evidence for some of his treatments is lacking, and later eradication of smallpox and development of antibiotics for tuberculosis rendered light therapy obsolete for these diseases. In the early 20th-century light therapy was promoted by Auguste Rollier and John Harvey Kellogg. In 1924, Caleb Saleeby founded The Sunlight League.
Sources: en.wikipedia.org
Dry powder is normally held at -20 °C or lower, away from light and moisture. Sealed vials can also be kept at 2-8 °C for shorter intervals. Warming to room temperature before opening prevents condensation.
In solution, hydrolysis of peptide bonds and oxidation of the methionine residue are the principal concerns. Oxidation converts methionine to its sulfoxide form, shifting the mass by sixteen daltons. Both processes are slowed by cold storage and by avoiding alkaline conditions.
A certificate documents what the supplier measured on a specific lot, not how a laboratory will use the material. Independent verification of identity and purity is common practice. Acceptance criteria should be defined before a batch is ordered.
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.