If you have been reading about thiol and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2026-08-01. Numbers and descriptions here follow the published literature rather than marketing material.
Synthesis occurs in two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine to complete the tripeptide. The pathway is feedback-inhibited by GSH and limited by cysteine availability, so cysteine supply often constrains production. Once formed, GSH participates in redox buffering, xenobiotic conjugation, and protein glutathionylation. Glutathione peroxidase uses GSH to reduce hydrogen peroxide and lipid peroxides, yielding GSSG, while glutathione reductase regenerates GSH using NADPH. Glutathione S-transferases conjugate electrophiles to GSH, supporting detoxification and excretion.
Because GSH is central to redox balance, its status is studied in aging, liver disease, neurodegenerative conditions, and metabolic disorders. Observational studies often report lower GSH or higher GSSG in affected tissues, but such associations do not establish that raising glutathione changes disease outcomes. Oral glutathione is digested into amino acids, and whether intact absorption occurs remains debated; precursors such as N-acetylcysteine and cysteine donors are also investigated. Regulatory agencies generally treat glutathione as a dietary supplement, not an approved drug, and clinical claims require evidence from controlled trials.
Storage recommendations for glutathione reagents usually specify a cool, dry, dark environment because the thiol oxidizes in air and light. Solid material is often kept desiccated at low temperature, while solutions are prepared fresh or stored frozen in aliquots. Repeated freeze-thaw cycles can accelerate degradation, and metal ions can catalyze oxidation. Quality control may include purity assays, water content, and identity confirmation. Stability limits are method-specific, so a stated shelf life applies only to defined conditions and packaging.
Laboratory measurement of glutathione requires attention to oxidation before analysis. Blood, tissue, or cell samples can lose reduced glutathione as it converts to GSSG or forms mixed disulfides with proteins. Acid extraction, rapid freezing, and thiol-blocking reagents are common strategies to preserve the original distribution. Reported concentrations therefore depend on collection protocol, extraction method, and the time between sampling and analysis. Comparisons across studies are most reliable when these pre-analytical variables are described.
Common analytical approaches include enzymatic recycling assays, high-performance liquid chromatography, and mass spectrometry. The enzymatic recycling assay uses glutathione reductase and a colorimetric or fluorometric reagent to amplify signal, which gives good sensitivity for total glutathione. Chromatographic methods can separate GSH from GSSG and related thiols, while mass spectrometry offers structural confirmation and multiplexing. Each approach has different requirements for calibration, internal standards, and validation. No single method captures every form of glutathione in every matrix.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Tripeptide of glutamate, cysteine, and glycine. |
| Molar mass | 307.32 g/mol | Calculated from the molecular formula. |
| Appearance | White to off-white powder | Typically crystalline or lyophilized solid. |
| Solubility | Soluble in water; insoluble in ethanol | Aqueous solutions are acidic and prone to oxidation. |
| Typical storage | -20 °C, desiccated, protect from light | Reduce exposure to oxygen and moisture. |
Cells synthesize glutathione through two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine, and glutathione synthetase adds glycine to form the complete tripeptide. Breakdown occurs through gamma-glutamyl transpeptidase and subsequent peptidase reactions, forming the gamma-glutamyl cycle. Within cells, glutathione also forms a disulfide-linked dimer called GSSG when two GSH molecules react. The balance between GSH and GSSG is widely used as an indicator of oxidative conditions, although the ratio can vary by compartment and tissue.
Glutathione supports several cellular processes beyond direct antioxidant action. It serves as a cofactor for glutathione peroxidase and glutathione S-transferase enzymes, which reduce peroxides and conjugate electrophiles, respectively. The molecule also acts as a reservoir of cysteine, an amino acid that can limit protein synthesis and redox signaling. In human nutrition, oral glutathione is sold as a supplement, but how much intact glutathione reaches tissues after ingestion remains an active research question. Clinical claims about supplementation are not uniformly supported by controlled trials.
Quality control for glutathione focuses on identity, purity, and oxidation state. Certificates of analysis may report assay value, water content, and the presence of GSSG or other impurities. Chromatographic purity is often expressed as a percentage of peak area. Reference standards help laboratories compare results across instruments and batches. Because glutathione is a small, polar molecule, separation from cysteine, gamma-glutamylcysteine, and related thiols can be challenging. Verification often combines more than one analytical technique.
Measuring glutathione requires attention to sample preparation because the molecule oxidizes readily. Blood, tissue, and cell samples are often treated with acid to precipitate proteins and stabilize the thiol. Without such steps, GSH can convert to GSSG or form mixed disulfides during storage. Analytical methods include spectrophotometric assays, high-performance liquid chromatography, and mass spectrometry. Each approach has different sensitivity, specificity, and susceptibility to interference from related compounds in complex matrices.
== Biosynthesis == The biosynthetic genes for cordycepin were fully characterized in 2017. The same set of genes also produce pentostatin, another adenosine derivative. Pentostatin protects cordycepin from being deaminated in the fungus, allowing the latter to accumulate. The biosynthetic cluster consists of four genes:
The IPCC Sixth Assessment Report summarized the scientific knowledge in 2021 for the future of ENSO as follows: "In the long term, it is very likely that the precipitation variance related to El Niño–Southern Oscillation will increase". The scientific consensus is also that "it is very likely that rainfall variability related to changes in the strength and spatial extent of ENSO teleconnections will lead to significant changes at regional scale".
The inverted terminal repeat (ITR) sequences comprise 145 bases each. They were named so because of their symmetry, which was shown to be required for efficient multiplication of the AAV genome. The feature of these sequences that gives them this property is their ability to form a hairpin, which contributes to so-called self-priming that allows primase-independent synthesis of the second DNA strand. The ITRs were also shown to be required for both integration of the AAV DNA into the host cell genome (19th chromosome in humans) and rescue from it, as well as for efficient encapsidation of the AAV DNA combined with generation of a fully assembled, deoxyribonuclease-resistant AAV particles. With regard to gene therapy, ITRs seem to be the only sequences required in cis next to the therapeutic gene: structural (cap) and packaging (rep) proteins can be delivered in trans. With this assumption many methods were established for efficient production of recombinant AAV (rAAV) vectors containing a reporter or therapeutic gene. However, it was also published that the ITRs are not the only elements required in cis for the effective replication and encapsidation. A few research groups have identified a sequence designated cis-acting Rep-dependent element (CARE) inside the coding sequence of the rep gene. CARE was shown to augment the replication and encapsidation when present in cis.
Neptunium at The Periodic Table of Videos (University of Nottingham) Lab builds world's first neptunium sphere Archived 2006-09-25 at the Wayback Machine, U.S. Department of Energy Research News NLM Hazardous Substances Databank – Neptunium, Radioactive Neptunium: Human Health Fact Sheet Archived 2004-02-06 at the Wayback Machine C&EN: It's Elemental: The Periodic Table – Neptunium
The cell's energy is equal to the voltage times the charge. Each gram of lithium represents Faraday's constant / 6.941(atomic mass), or 13,901 coulombs. At 3 V, this gives 41.7 kJ per gram of lithium, or 11.6 kWh per kilogram of lithium. This is slightly more than the heat of combustion of gasoline; however, lithium-ion batteries as a whole are still significantly heavier per unit of energy due to the additional materials used in production. Note that the cell voltages involved in these reactions are larger than the potential at which an aqueous solutions would electrolyze.
Sources: en.wikipedia.org
A composite mythological being with the body of a lion and the head of a human is present in the traditions, mythology and art of South and Southeast Asia. Variously known as puruṣamr̥ga (Sanskrit, "human-animal"), purushamirugam (Tamil, "human-animal"), naravirala (Sanskrit, "human-cat") in India, or as nara-simha (Sanskrit, "human-lion") in Sri Lanka, manussiha or manutthiha (Pali, "human-lion") in Myanmar, and norasingha (from Pali, "human-lion", a variation of the Sanskrit "nara-simha") or thep norasingha ("man-lion deity"), or nora nair in Thailand. Although, just like the "nara-simha", she/he has a head of a lion and the body of a human. In contrast to the sphinxes in Egypt, Mesopotamia, and Greece, of which the traditions largely have been lost due to the discontinuity of the civilization, the traditions related to the "Asian sphinxes" are very much alive today. The earliest artistic depictions of "sphinxes" from the South Asian subcontinent are to some extent influenced by Hellenistic art and writings. These hail from the period when Buddhist art underwent a phase of Hellenistic influence. Numerous sphinxes can be seen on the gateways of Bharhut stupa, dating to the 1st century B.C. In South India, the "sphinx" is known as puruṣamr̥ga (Sanskrit) or purushamirugam (Tamil), meaning "human-animal". It is found depicted in sculptural art in temples and palaces where it serves an apotropaic purpose, just as the "sphinxes" in other parts of the ancient world.
== Structure == The duodenum and the jejunum are the first and second parts of the small intestine, respectively. The suspensory muscle of the duodenum marks their formal division. The suspensory muscle arises from the right crus of the diaphragm as it passes around the esophagus, continues as connective tissue around the stems of the celiac artery and superior mesenteric artery, passes behind the pancreas, and enters the upper part of the mesentery, inserting into the junction between the duodenum and jejunum, the duodenojejunal flexure. Here, the muscles are continuous with the muscular layers of the duodenum.
== Veterinary use == Combined with marbofloxacin CAS number 115550-35-1and clotrimazole, dexamethasone is available under the name Aurizon, CAS number 50-02-2, and used to treat difficult ear infections, especially in dogs. It can also be combined with trichlormethiazide to treat horses with swelling of distal limbs and general bruising. Dexamethasone is also used for emergency patients with hypoadrenocorticism as the drug does not interfere with adrenocorticotropic hormone stimulation testing.
Morgan William Sulzer (1884), governor of New York J. Mayhew Wainwright (1884), U.S. congressman and assistant secretary of war Charles Henry Turner (1888), U.S. congressman from New York; doorkeeper of the United States House of Representatives 1891–1893 James W. Gerard (1890), U.S. ambassador to Germany 1913–1917 Victor M. Allen (1892), member of the New York State Senate John F. Carew (1893), U.S. congressman from New York Harvey R. Kingsley (1893), president pro tempore of the Vermont State Senate Edward Lazansky (1895), secretary of state of New York Carl L. Alsberg (1896), 2nd commissioner of Food and Drugs, head of the Food and Drug Administration 1912–1921 Lewis Einstein (1898), U.S. ambassador to Czechoslovakia and U.S. ambassador to Costa Rica John Purroy Mitchel (1899), mayor of New York City Montgomery Schuyler Jr. (1899), U.S. minister to El Salvador and U.S. minister to Ecuador Charles H. Tuttle (1899), U.S. attorney for the Southern District of New York and 1930 Republican nominee for governor of New York Henry W. Shoemaker (1901), folklorist, historian, diplomat; U.S. ambassador to Bulgaria 1930–1933 Martin C. Ansorge (1903), U.S. congressman from New York Stanley M. Isaacs (1903), Manhattan borough president 1938–1942 Allen J. Bloomfield (1094), member of the New York State Assembly and the New York State Senate Fred Biermann (1905), U.S. congressman from Iowa John Collier (1906), U.S. commissioner of Indian Affairs Meyer Robert Guggenheim* (1907), U.S. ambassador to Portugal 1953–1954, grandson of Meyer Guggenheim Joseph C.
Sources: en.wikipedia.org
Tofisopam (Emandaxin, Grandaxin, Sériel) is an anxiolytic that is marketed in several European countries. Chemically, it is a 2,3-benzodiazepine. Unlike other anxiolytic benzodiazepines (which are generally 1,4- or 1,5-substituted) however, tofisopam does not have anticonvulsant, sedative, skeletal muscle relaxant, motor skill-impairing or amnestic properties. While it may not be an anticonvulsant in and of itself, it has been shown to enhance the anticonvulsant action of classical 1,4-benzodiazepines (such as diazepam) and muscimol, but not sodium valproate, carbamazepine, phenobarbital, or phenytoin. Tofisopam is indicated for the treatment of anxiety and alcohol withdrawal, and is prescribed in a dosage of 50–300 mg per day divided into three doses. Peak plasma levels are attained two hours after an oral dose. Tofisopam is not reported as causing dependence to the same extent as other benzodiazepines, but is still recommended to be prescribed for a maximum of 12 weeks. Tofisopam is not approved for sale in the United States or Canada. However, Vela Pharmaceuticals of New Jersey is developing the D-enantiomer (dextofisopam) as a treatment for irritable bowel syndrome, with moderate efficacy demonstrated in clinical trials so far. Tofisopam is also claimed to be a PDE10A inhibitor, which may provide an alternative mechanism of action for its various therapeutic effects, and this action has been proposed to make tofisopam potentially useful as a treatment for schizophrenia.
is the concentration of the solid in the diffusion layer surrounding the solid. D is the diffusion coefficient. L is the diffusion layer thickness. As can be inferred from the Noyes–Whitney equation, the rate of dissolution may be modified primarily by altering the surface area of the solid by altering the particle size (e.g., with micronization). For many drugs, reducing the particle size reduces the dose needed to achieve the same therapeutic effect. The particle size reduction increases the specific surface area and the dissolution rate and does not affect solubility. The rate of dissolution may also be altered by choosing a suitable polymorph of a compound. Different polymorphs have different solubility and dissolution rate characteristics. Specifically, crystalline forms dissolve slower than amorphous forms since they require more energy to leave the lattice during dissolution. The stablest crystalline polymorph has the lowest dissolution rate. Dissolution also differs between anhydrous and hydrous forms of a drug. Anhydrous forms often dissolve faster but sometimes are less soluble. Esterification is also used to control solubility. For example, stearate and estolate esters of drugs have decreased solubility in gastric fluid. Later, esterases in the gastrointestinal tract (GIT) wall and blood hydrolyze these esters to release the parent drug. Coatings on a tablet or pellet may act as barriers to reducing the dissolution rate. Coatings may also be used to control where dissolution takes place.
The Economist reports that China has become a "scientific superpower", citing numerous examples of its rapid development across a wide range of fields. 20 June – Following a surge in population of the Iberian lynx – from 62 mature individuals in 2001 to 648 in 2022 – the International Union for Conservation of Nature removes the animal from its "endangered" list, classing the animal as "vulnerable" instead. 24 June – The discovery of three Super-Earth candidates around HD 48948, a K-type dwarf star located 55 light-years away, is reported. One planet lies within the habitable zone. 25 June – China's Chang'e 6 lunar exploration mission successfully returns to Earth after taking rock and soil samples from the far side of the Moon. The orbiter proceeded on a mission to carry out observations at Sun-Earth Lagrange point L2 after dropping the sample off to Earth. Promising results of health and medical research are reported: a blood AI test of plasma proteins that predicts Parkinson's disease up to 7 years before symptom onset (18 June), walking programs as a cost-effective method against lower back pain recurrence (19 June). Hazard research is published: a study finds toxic metals including lead and arsenic in tampons (22 June), and a study indicates ocean water intrusion causing Antarctic ice-sheet grounding zones melting is a further tipping point in the climate system (25 June).
=== Archaeobotanical record and ruderal habitat === The interaction between the Moche and this wild species is supported by its ecological behavior and archaeobotanical findings in the La Libertad Region. Solanum pimpinellifolium behaves as a ruderal plant, proliferating naturally and constantly along the edges of irrigation canals, ditches, and humid depressions built by pre-Hispanic agricultural engineers. Contemporary botanical and archaeological inventories have recorded stable populations of this wild tomato growing directly over the cultural contexts of major Moche political-religious centers, such as the El Brujo Arqueological Complex (in the Chicama Valley) and near the Huaca del Rosario (in Magdalena de Cao). This resource holds high scientific and historical value because Peru is a key center of origin for the tomato, hosting 14 of the world's 17 tomato species. Research by Peru's Ministry of the Environment indicates that roughly 90% of the genes in modern commercially cultivated tomatoes worldwide originate from these wild Andean relatives, which contributed high natural sugar levels and lycopene content to ancient diets.
AAS are banned by all major sports bodies including Association of Tennis Professionals, Major League Baseball, Fédération Internationale de Football Association, the Olympics, the National Basketball Association, the National Hockey League, World Wrestling Entertainment and the National Football League. The World Anti-Doping Agency (WADA) maintains the list of performance-enhancing substances used by many major sports bodies and includes all anabolic agents, which includes all AAS and precursors as well as all hormones and related substances.
Sources: en.wikipedia.org
GSH is the reduced, thiol-containing form of glutathione, while GSSG is the oxidized disulfide dimer formed when two GSH molecules react. Cells maintain a high GSH-to-GSSG ratio under normal conditions. A shift toward GSSG is often interpreted as oxidative stress, though sample handling can affect the measured ratio.
No. It is a tripeptide made from three amino acids: glutamate, cysteine, and glycine. The gamma-glutamyl bond is unusual and distinguishes it from typical peptide linkages.
Most ingested glutathione is broken down in the gastrointestinal tract into its constituent amino acids. Some formulations may protect it from digestion, but intact absorption and delivery to specific tissues remain uncertain. Research continues on precursors and delivery methods.
Pre-analytical handling, extraction chemistry, and detection method all influence reported glutathione values. Oxidation during sample processing can shift the measured GSH/GSSG ratio. Standardized protocols and reference materials help reduce, but do not eliminate, these differences.