The short version of thiol fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-12 and is reviewed periodically as new material appears.
Functionally, glutathione supports redox balance by donating electrons and becoming oxidized. It also serves as a cofactor for enzymes such as glutathione peroxidases and glutathione S-transferases. These enzymes participate in peroxide reduction and in conjugation reactions that help process reactive molecules. Separate from antioxidant roles, glutathione can modify protein cysteines through S-glutathionylation, influencing enzyme activity and signaling. Research continues to examine how these chemical roles translate into whole-organism effects.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its glutamate-cysteine linkage uses the gamma-carboxyl group of glutamate, a feature that resists standard peptidases. The cysteine residue provides a thiol group, which gives the molecule its reducing character. In cells, glutathione is often the most abundant small-molecule thiol, with concentrations varying widely by tissue and compartment. It exists mainly in a reduced form called GSH, while oxidation produces a disulfide-linked dimer called GSSG.
Biosynthesis proceeds in two ATP-dependent steps. First, glutamate-cysteine ligase joins glutamate and cysteine. Second, glutathione synthetase adds glycine to the intermediate. The pathway is regulated by cysteine availability, enzyme expression, and feedback inhibition by glutathione itself. Liver tissue has a particularly high capacity for synthesis and export. Because the molecule is made inside cells, circulating glutathione reflects a balance of release, uptake, and breakdown rather than simple dietary supply.
Quality control for glutathione measurements includes calibration with authenticated standards, internal standards where available, blank correction, and spike recovery checks. Because glutathione can form during sample processing or degrade before analysis, pre-analytical handling is a major source of variability. Interlaboratory comparisons often show differences in reported values due to method-specific calibration and detection principles. Interpretive thresholds are context-dependent, and no single reference range applies across all tissues or matrices. Researchers generally report both reduced and oxidized forms, along with the method and sample handling details.
Quantification of glutathione in biological or food samples commonly uses liquid chromatography coupled to ultraviolet, fluorescence, electrochemical, or mass spectrometric detection. Because the thiol group oxidizes readily, samples are often acidified or derivatized immediately after collection to stabilize reduced glutathione. Enzymatic recycling assays and colorimetric kits offer higher throughput but generally lower specificity than chromatographic methods. Mass spectrometry can distinguish glutathione from related thiols and allow simultaneous measurement of oxidized forms. Reported concentrations depend strongly on sample type, extraction procedure, and analytical platform.
Glutathione reference materials are sensitive to oxygen, light, and elevated temperature. Solid material is typically stored desiccated at -20 °C or below, while solutions require tighter control because thiol oxidation proceeds faster in liquid form. Aqueous solutions are often prepared fresh, kept cold, and protected from air; some protocols add acid or chelating agents to slow metal-catalyzed oxidation. Repeated freeze-thaw cycles can accelerate degradation and should be avoided. Stability data vary by matrix, so laboratories usually verify performance with their own storage conditions.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione (reduced form) | Often abbreviated GSH |
| Chemical class | Tripeptide | Contains glutamate, cysteine, and glycine |
| Molecular formula | C10H17N3O6S | Refers to the reduced form |
| Molar mass | 307.32 g/mol | Calculated for C10H17N3O6S |
| Appearance | White to off-white powder | Typical laboratory-grade solid |
Glutathione synthesis proceeds in two ATP-dependent steps catalyzed by glutamate-cysteine ligase and glutathione synthetase. The first step joins glutamate and cysteine to form gamma-glutamylcysteine and is generally rate-limiting. The second step adds glycine to complete the tripeptide. Cysteine availability, feedback inhibition by glutathione, and oxidative conditions influence flux through this pathway. The pathway is conserved across many organisms, and degradation by gamma-glutamyl transpeptidase and related peptidases recycles amino acids for new synthesis.
Within cells, glutathione serves as a cofactor for glutathione peroxidases and glutathione S-transferases. These enzymes reduce hydrogen peroxide and organic peroxides or conjugate electrophilic compounds to the thiol group. The resulting conjugates can be exported and processed through mercapturic acid pathways. Glutathione also contributes to protein thiol homeostasis and to recycling of other antioxidants such as ascorbate. Its precise roles vary by tissue, and many regulatory effects observed in laboratory systems remain difficult to quantify in whole organisms.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It occurs in nearly all living cells, with highest concentrations in liver, kidney, and red blood cells, and exists in reduced (GSH) and oxidized disulfide (GSSG) forms. The cysteine thiol group enables reversible oxidation and reduction reactions. This property makes glutathione a central participant in cellular redox balance. The balance between these forms is often used as an indicator of oxidative stress.
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.
Glutathione is present in most tissues, with especially high concentrations in the liver. It also serves as a cofactor for some enzymes and helps transport amino acids across cell membranes. In plants and microorganisms, glutathione contributes to stress responses and metal handling. The molecule is synthesized in two ATP-dependent steps, first producing gamma-glutamylcysteine and then adding glycine. Because cysteine availability often limits synthesis, dietary and metabolic factors can influence glutathione levels. Research continues to examine how these levels relate to health and disease.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group. This unusual linkage protects the molecule from many common peptidases. The cysteine side chain carries a thiol group that can undergo reversible oxidation. Because of this thiol, glutathione participates in redox reactions and helps maintain the reducing environment inside most cells in living systems.
Enzymatic recycling assays provide a complementary approach for total glutathione. In these methods, glutathione reductase reduces oxidized glutathione while a thiol-reactive reagent, such as 5,5'-dithiobis(2-nitrobenzoic acid), produces a colored product. The reaction cycles between reduced and oxidized forms, amplifying the signal. Spectrophotometric or fluorometric detection can then estimate concentration. Distinguishing reduced glutathione from glutathione disulfide often requires separate aliquots, masking agents, or chromatographic separation, and the choice affects reported values.
Storage conditions strongly influence glutathione stability. The solid reduced form is commonly kept desiccated at or below minus twenty degrees Celsius, protected from light and moisture. Aqueous solutions are less stable because the thiol group reacts with dissolved oxygen, and oxidation accelerates at neutral or alkaline pH. Acidic solutions and oxygen-free handling can slow degradation, but repeated freeze-thaw cycles should be avoided. Researchers often verify concentration before use, because apparent losses can arise from oxidation or water uptake.
Measuring glutathione in biological samples requires attention to oxidation and matrix effects. High-performance liquid chromatography with ultraviolet or fluorescence detection can separate reduced and oxidized forms after derivatization. Liquid chromatography with tandem mass spectrometry offers higher specificity and can quantify glutathione alongside related thiols. Because glutathione can oxidize during sample handling, many protocols use rapid acidification with metaphosphoric acid or sulfosalicylic acid. Internal standards help correct for losses during extraction and analysis.
In contrast to the maternal bond, paternal bonds tend to vary over the span of a child's development in terms of both strength and stability. In fact, many children now grow up in fatherless households and do not experience a paternal bond at all. In general, paternal bonding is more dominant later in a child's life after language develops. Fathers may be more influential in play interactions as opposed to nurturance interactions. Father–child bonds also tend to develop with respect to topics such as political views or money, whereas mother–child bonds tend to develop in relation to topics such as religious views or general outlooks on life. In 2003, a researcher from Northwestern University in Illinois found that progesterone, a hormone more usually associated with pregnancy and maternal bonding, may also control the way men react towards their children. Specifically, they found that a lack of progesterone reduced aggressive behavior in male mice and stimulated them to act in a fatherly way towards their offspring.
The electron capture detector is used for detecting electron-absorbing components (high electronegativity) such as halogenated compounds in the output stream of a gas chromatograph. The ECD uses a radioactive beta particle (electron) emitter in conjunction with a so-called makeup gas flowing through the detector chamber. The electron emitter typically consists of a metal foil holding 10 millicuries (370 MBq) of the radionuclide 63Ni. Usually, nitrogen is used as makeup gas, because it exhibits a low excitation energy, so it is easy to remove an electron from a nitrogen molecule. The electrons emitted from the electron emitter collide with the molecules of the makeup gas, resulting in many more free electrons. The electrons are accelerated towards a positively charged anode, generating a current. There is therefore always a background signal present in the chromatogram. As the sample is carried into the detector by the carrier gas, electron-absorbing analyte molecules capture electrons and thereby reduce the current between the collector anode and a cathode. Over a wide range of concentrations the rate of electron capture is proportional to the analyte concentration. ECD detectors are particularly sensitive to halogens, organometallic compounds, nitriles, or nitro compounds.
==== Legal Considerations ==== In the United States brands applied by any method often must be registered with a state or county office. In some jurisdictions, it is illegal to brand an animal without first registering the design with a state office. The following table summarizes the legal recognition and requirements for equine freeze brands in the United States:
This regulates the reaction catalyzing fructose 2,6-bisphosphate (a potent activator of phosphofructokinase-1, the enzyme that is the primary regulatory step of glycolysis) by slowing the rate of its formation, thereby inhibiting the flux of the glycolysis pathway and allowing gluconeogenesis to predominate. This process is reversible in the absence of glucagon (and thus, the presence of insulin). Glucagon stimulation of PKA inactivates the glycolytic enzyme pyruvate kinase, inactivates glycogen synthase, and activates hormone-sensitive lipase, which catabolizes glycerides into glycerol and free fatty acid(s), in hepatocytes. Glucagon also inactivates acetyl-CoA carboxylase (ACC), which creates malonyl-CoA from acetyl-CoA, through cAMP-dependent and/or cAMP-independent kinases. Malonyl-CoA is a product formed by ACC during denovo synthesis and an allosteric inhibitor of carnitine palmitoyltransferase I (CPT1), a mitochondrial enzyme important for bringing fatty acids into the intermembrane space of the mitochondria for β-oxidation. Glucagon decreases malonyl-CoA through inhibition of acetyl-CoA carboxylase and through reduced glycolysis through its aforementioned reduction in Fructose 2,6-bisphosphate. Thus, reduction in malonyl-CoA is a common regulator for the increased fatty acid metabolism effects of glucagon.
== AFL career == Myers is originally from Perth in the WAFL, he also attended Wesley College, Perth. He was drafted with the 6th overall selection in the 2007 national draft by Essendon. Myers, along with 33 other Essendon players, was found guilty of using a banned performance-enhancing substance, thymosin beta-4, as part of Essendon's sports supplements program during the 2012 season. He and his team-mates were initially found not guilty in March 2015 by the AFL Anti-Doping Tribunal, but a guilty verdict was returned in January 2016 after an appeal by the World Anti-Doping Agency. He was suspended for two years which, with backdating, ended in November 2016; as a result, he served approximately fourteen months of his suspension and missed the entire 2016 AFL season. The suspension lead to speculation that Myers would exercise his rights as an unrestricted free agent and leave Essendon, but during the year he signed a three-year contract to remain with Essendon until the end of the 2019 season. Myers announced his retirement at the end of the 2019 season with an open letter to the fans.
Sources: en.wikipedia.org
Without sexual stimulation, and therefore lack of activation of the NO/cGMP system, sildenafil should not cause an erection. Other drugs that operate by the same mechanism include tadalafil (Cialis) and vardenafil (Levitra). Sildenafil is broken down in the liver by hepatic metabolism using cytochrome p450 enzymes, mainly CYP450 3A4 (major route), but also by CYP2C9 (minor route) hepatic isoenzymes. The major product of metabolisation by these enzymes is N-desmethylated sildenafil, which is metabolised further. This metabolite also has an affinity for the PDE receptors, about 40% of that of sildenafil. Thus, the metabolite is responsible for about 20% of sildenafil's action. Sildenafil is excreted as metabolites predominantly in the feces (about 80% of administered oral dose) and to a lesser extent in the urine (around 13% of the administered oral dose). If taken with a high-fat meal, absorption is reduced; the time taken to reach the maximum plasma concentration increases by around one hour, and the maximum concentration itself is decreased by nearly one-third.
S-formylmycothiol + NADH + + The two substrates of this enzyme are S-(hydroxymethyl)mycothiol and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are S-formylmycothiol, reduced NADH, and a proton. The enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is formaldehyde:NAD+ oxidoreductase (mycothiol-formylating). This enzyme is also called NAD/factor-dependent formaldehyde dehydrogenase or S-(hydroxymethyl)mycothiol dehydrogenase.
With Robert J. Flaherty's Nanook of the North in 1922, documentary film embraced romanticism. Flaherty filmed a number of heavily staged romantic documentary films during this time period, often showing how his subjects would have lived 100 years earlier and not how they lived right then. For instance, in Nanook of the North, Flaherty did not allow his subjects to shoot a walrus with a nearby shotgun, but had them use a harpoon instead. Some of Flaherty's staging, such as building a roofless igloo for interior shots, was done to accommodate the filming technology of the time. Paramount Pictures tried to repeat the success of Flaherty's Nanook and Moana with two romanticized documentaries, Grass (1925) and Chang (1927), both directed by Merian C. Cooper and Ernest Schoedsack.
==== United Arab Emirates ==== Franchise partner Alshaya Group opened its first Chipotle restaurant in the United Arab Emirates in Dubai at the Jumeirah Beach Residence in September 2024. Alshaya opened its first location in Abu Dhabi at the Yas Mall, the third in the UAE, in August 2025.
Sources: en.wikipedia.org
Klibanski became chief of the Neuroendocrine Unit at Massachusetts General Hospital, studying hormones and neuroendocrinology with a focus on hypopituitarism and pituitary tumors. Her clinical research has also examined the effects of hypothalamic and pituitary disorders on body composition and bone density, including bone loss associated with anorexia nervosa and growth hormone deficiency. In 1997, Klibanski became the first woman from Mass General's Department of Medicine to become a professor of medicine at Harvard. She has authored more than 350 peer-reviewed papers and book chapters and has received the Endocrine Society Clinical Investigator Award and the Clinical Endocrinology Trust Medal from the Society for Endocrinology. Klibanski has served on the National Institute of Diabetes and Digestive and Kidney Diseases Board of Counselors and the editorial board of the Journal of Clinical Endocrinology and Metabolism, and is a past president of the Pituitary Society. She established the Center for Faculty Development at Massachusetts General Hospital and mentored more than fifty women, for which she received the Endocrine Society's Outstanding Mentor Award.
{\displaystyle {\begin{cases}{\ce {^{235}_{92}U + ^{1}_{0}n -> ^{236m}_{92}U ->[][120 \ {\ce {ns}}] ^{236}_{92}U + \gamma}}\\{\ce {^{236}_{92}U + ^{1}_{0}n -> ^{237}_{92}U ->[\beta^-][6.75 \ {\ce {d}}] ^{237}_{93}Np}}\end{cases}}}
== Licensing == A New Drug Application for saxagliptin in the treatment of type 2 diabetes was submitted to the FDA in June 2008. It was based on a drug development program with 8 randomized trials: 1 phase 2 dose-ranging (2.5–100 mg/d) study; 6 phase 3, 24-week controlled trials with additional controlled follow-up from 12 to 42 months, double-blinded throughout; and one 12-week mechanism-of-action trial with a 2-year follow-up period. The FDA approved saxagliptin with brand name Onglyza on July 31, 2009. Saxagliptin was licensed for use throughout the European Union by the European Medicines Agency on December 1, 2009. Bristol-Myers Squibb announced on 27 December 2006 that Otsuka Pharmaceutical Co. has been granted exclusive rights to develop and commercialize the compound in Japan. Under the licensing agreement, Otsuka will be responsible for all development costs, but Bristol-Myers Squibb retains rights to co-promote saxagliptin with Otsuka in Japan. Further, on 11 January 2007 it was announced that Bristol-Myers Squibb and AstraZeneca would work together to complete development of the drug and in subsequent marketing.
These plans had been made some time ago." Russian military intelligence source alleged that the United States knew the date when the war in South Ossetia would begin because the United States military delegation cancelled the visit to Russia, which was scheduled on 10-14 August, on August 1 and cited the absence of the Russian permit for the flight. In late August 2008, Batu Kutelia, the deputy defence minister told the Financial Times that the decision to take Tskhinvali was made in spite of the fact that Georgia did not have enough anti-tank and air defences because "At some point there was no choice." He also said that Georgian authorities and military did not expect Russia to use a large-scale force against Georgia. In August 2008, Steven Pifer, former Ambassador to Ukraine, said that there were signs that the Russian invasion had been prepared in advance, with Russia waiting for Georgia to fall in a trap and using the Georgian response as a pretext. Secretary of State for Foreign and Commonwealth Affairs David Miliband visited Ukraine in late August and told Ukrainians "not to provide any pretext" for Russia. He said, "The Russians have used those pretexts in the Georgian case and it's important to not repeat that." Georgian reintegration minister Temur Iakobashvili said, "The pilots we captured reported that they were mobilized days before Aug. 8.
== Controlled == Certain surgeries for cerebral aneurysms or aortic arch defects require that blood circulation be stopped while repairs are performed. This deliberate temporary induction of clinical death is called circulatory arrest. It is typically performed by lowering body temperature to between 18 °C and 20 °C (64 and 68 °F) and stopping the heart and lungs. This state is called deep hypothermic circulatory arrest. At such low temperatures most patients can tolerate the clinically dead state for up to 30 minutes without incurring significant brain injury. Longer durations are possible at lower temperatures, but the usefulness of longer procedures has not been established yet. Controlled clinical death has also been proposed as a treatment for exsanguinating trauma to create time for surgical repair.
Sources: en.wikipedia.org
Glutathione is a sulfur-containing tripeptide made from glutamate, cysteine, and glycine. It is found in most cells and participates in redox balance and detoxification reactions.
No. It is a tripeptide assembled from three amino acids. The term amino acid applies to the individual building blocks, not to the assembled molecule.
It is present in many tissues, with especially high amounts in liver. Intracellular concentrations are generally much higher than those found in blood plasma.
Acidification lowers pH and helps prevent oxidation of the thiol group during extraction and storage. It can also precipitate proteins and stabilize the reduced form before analysis.