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 2025-10-18 and is reviewed periodically as new material appears.
In cells, glutathione helps maintain the reducing environment of the cytosol and supports enzymes that counteract reactive oxygen species. It acts as a cofactor for glutathione peroxidases, which reduce hydrogen peroxide and lipid peroxides, and for glutathione S-transferases, which conjugate electrophiles. The ratio of GSH to GSSG is often used as an indicator of oxidative stress, although the ratio can vary by compartment and cell type. Glutathione also stores cysteine, an amino acid that can be limiting for protein synthesis and antioxidant defense.
Synthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine to form gamma-glutamylcysteine, and glutathione synthetase adds glycine. The first step is rate-limiting and is influenced by cysteine availability and feedback inhibition by GSH. Breakdown involves gamma-glutamyl transferase and subsequent peptidases, which release constituent amino acids for reuse. Because turnover differs among tissues, measurements from blood, plasma, and tissues are not directly interchangeable. Research continues to clarify how compartment-specific pools are regulated in health and disease.
Glutathione is a small sulfur-containing peptide built from glutamic acid, cysteine, and glycine. Its distinctive feature is a gamma-glutamyl bond between glutamate's side-chain carboxyl group and cysteine's amino group. This linkage resists ordinary peptidases and helps the molecule remain stable inside cells. The reduced thiol form, often abbreviated GSH, is the dominant intracellular species. The oxidized disulfide dimer, GSSG, forms when two reduced molecules link through their cysteine sulfur atoms. The balance between these forms is a common redox indicator.
In living systems, glutathione occurs in millimolar concentrations in many cell types, while extracellular levels are generally much lower. The liver holds a substantial share of the body's total pool, and the molecule participates in reduction, detoxification, and amino acid transport. It also serves as a cofactor for enzymes such as glutathione peroxidase and glutathione S-transferase. Because the cysteine residue supplies a reactive thiol, glutathione can donate electrons and become oxidized. Cells regenerate reduced glutathione through glutathione reductase using NADPH.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | For reduced glutathione; the oxidized dimer has two sulfur atoms. |
| Molar mass | 307.32 g/mol | Calculated for the reduced form. |
| Appearance | White to off-white crystalline powder | Typical for solid reagent; solutions are usually colorless. |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar organic solvents. |
| Typical storage | -20 °C, desiccated, protected from light | Limits oxidation, moisture uptake, and degradation. |
Glutathione is a small tripeptide built from glutamic acid, cysteine, and glycine. Its peptide bond between glutamate and cysteine involves the gamma-carboxyl group rather than the usual alpha-carboxyl group. This structure gives the molecule a reactive thiol on the cysteine residue. The reduced form, often abbreviated GSH, is the predominant intracellular species in many cell types. Because the thiol can donate electrons, glutathione participates in redox chemistry and in the conjugation of reactive molecules.
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.
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.
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.
In cells, glutathione exists mainly in a reduced form called GSH. When two GSH molecules react, they form oxidized glutathione, or GSSG, which contains a disulfide bond. The ratio of GSH to GSSG is often used as an indicator of oxidative stress. Enzymes such as glutathione peroxidase and glutathione reductase help cycle the molecule between these two states. This cycling supports antioxidant defense, detoxification of reactive molecules, and regulation of certain signaling pathways.
=== 15 September === The RSF claimed to have retaken Kazgeil and Al-Riash in North Kordofan. The RSF was accused of forcibly displacing residents of the village of Tura, north of El Fasher, and converting it into a garrison.
== Recent publications == Bale, Sue; V. Jones (2004). Wound Care Nursing, 2nd Edition - A Patient-Centered Approach. Mosby Ltd. ISBN 0-7234-3344-5. Bale, Sue; N. Tebble; V.J. Jones; P.Price (2004). "The benefits of implementing a new skin care protocol in nursing homes". Journal of Tissue Viability. 14 (2): 44–50. PMID 15114926. Bale, Sue; N. Tebble; P. Price (2004). "A topical metronidazole gel used to treat malodorous wounds". British Journal of Nursing. 13 (11): S4–11. PMID 15218439. Jones, V.; S. Bale; K.G. Harding (2004). Acute and chronic wound healing. In "Wound Care Essentials Practice" (S. Baronowski & E.A. Ayello, eds. Lippincott Williams and Wilkins. ISBN 1-58255-274-6.
Shriram Gadhve of All India Vegetable Growers Association (AIVGA) claims his organisation supports retail reform. He claimed that currently, it is the middlemen commission agents who benefit at the cost of farmers. He urged that the retail reform must focus on rural areas and that farmers receive benefits. Gadhve claimed, "A better cold storage would help since this could help prevent the existing loss of 34% of fruits and vegetables due to inefficient systems in place." AIVGA operates in nine states including Maharashtra, Andhra Pradesh, West Bengal, Bihar, Chhattisgarh, Punjab and Haryana with 2,200 farmer outfits as its members. Bharat Krishak Samaj, a farmer association with more than 75,000 members says it supports retail reform. Ajay Vir Jakhar, the chairman of Bharat Krishak Samaj, claimed a monopoly exists between the private guilds of middlemen, commission agents at the sabzi mandis (India's wholesale markets for vegetables and farm produce) and the small shopkeepers in the unorganised retail market. Given the perishable nature of food like fruit and vegetables, without the option of safe and reliable cold storage, the farmer is compelled to sell his crop at whatever price he can get. He cannot wait for a better price and is thus exploited by the current monopoly of middlemen. Jakhar asked that the government make it mandatory for organised retailers to buy 75% of their produce directly from farmers, bypassing the middlemen monopoly and India's sabzi mandi auction system. Consortium of Indian Farmers Associations (CIFA) announced its support for retail reform.
Sources: en.wikipedia.org
=== Ethylene === Pyrolysis is used to produce ethylene, the chemical compound produced on the largest scale industrially (>110 million tons/year in 2005). In this process, hydrocarbons from petroleum are heated to around 600 °C (1,112 °F) in the presence of steam; this is called steam cracking. The resulting ethylene is used to make antifreeze (ethylene glycol), PVC (via vinyl chloride), and many other polymers, such as polyethylene and polystyrene.
== Further reading == Burger, R., U.S. patent 872,795, "Double walled vessel with a space for a vacuum between the walls," December 3, 1907. Sella, Andrea (August 2008). "Dewar's Flask". Chemistry World: 75. Retrieved 2008-08-30.
== Operation Atlantic Resolve == On 29 March 2017, the Department of Defense reported that Green Berets from 1st Battalion 10th SFG were deployed to Europe to take part in exercise Allied Spirit VI-a multinational training exercise involving military personnel from Canada, Czech Republic, Estonia, Finland, France, Hungary, Germany, Italy, Macedonia, Kosovo, Latvia, the Netherlands, Slovenia, UK and US at the JMRC in Germany, the exercise involved special operations and conventional forces with the aim to increase their effectiveness and/particularly to increase the effectiveness of special operations forces in working together while bolstering the capabilities of partner nations within US European Command's area of responsibility. The Green Berets provided their advise and assist training/skills, whilst working with Estonian Special Operations Task Group troops and Macedonian special operations troops. US Army Major Robert Temple, the special operations force cell planner at the JMRC said that “The primary purpose of this exercise is providing a venue for the 1st Latvian Brigade to train in a Joint Task Force environment and increase their interoperability with both U.S. units as well as other multinational forces.” The exercise is being conducted as part of Operation Atlantic Resolve.
Sources: en.wikipedia.org
When gunfights finally erupted outside and around the television studio, they were almost always the result of miscommunication. One such example is when a group of Patriotic Guardsmen took up a defensive position in a building close to the television centre on the 23rd. It has not been established who took the first shots at around 17:00, but a gunfight soon ensued with those in the television station returning fire onto the position of the Patriotic guards, according to an aid worker who had set up a first aid station at the side of the television station, and who said that, afterwards, the group of Patriotic Guardsmen would later deny that they had fired first. This is only one of many examples of gunfights between pro-revolution forces after the flight of Ceaușescu on the 22nd. Scenes of major gunfights during this period include the television, radio and telephone buildings, as well as Casa Scânteii (the nation's print media center, which serves a similar role today under the name of the "House of the Free Press", Casa Presei Libere) and the post office in the district of Drumul Taberei; Palace Square (site of the Central Committee building, but also of the Central University Library, the national art museum in the former Royal Palace, and the Ateneul Român (Romanian Athenaeum), Bucharest's leading concert hall); the university and the adjoining University Square (one of the city's main intersections); Otopeni and Băneasa airports; hospitals; and the Ministry of Defence.
Cordelia goes to Alastair to gently break the news of Charles’ new engagement to him. Alastair already knew and is not happy when Cordelia tells him she eavesdropped on his recent conversation with Charles.
=== South America === The effects of El Niño in South America are direct and strong. An El Niño is associated with warm and very wet weather months in April–October along the coasts of northern Peru and Ecuador, causing major flooding whenever the event is strong or extreme. Because El Niño's warm pool feeds thunderstorms above, it creates increased rainfall across the east-central and eastern Pacific Ocean, including several portions of the South American west coast. The effects of El Niño in South America are direct and stronger than in North America. An El Niño is associated with warm and very wet weather months in April–October along the coasts of northern Peru and Ecuador, causing major flooding whenever the event is strong or extreme. The effects during the months of February, March, and April may become critical along the west coast of South America, El Niño reduces the upwelling of cold, nutrient-rich water that sustains large fish populations, which in turn sustain abundant sea birds, whose droppings support the fertilizer industry. The reduction in upwelling leads to fish kills off the shore of Peru. The local fishing industry along the affected coastline can suffer during long-lasting El Niño events. Peruvian fisheries collapsed during the 1970s due to overfishing following the 1972 El Niño Peruvian anchoveta reduction. The fisheries were previously the world's largest, however, this collapse led to the decline of these fisheries.
Sources: en.wikipedia.org
GSH is the reduced form with a free thiol group, while GSSG is the oxidized disulfide-linked dimer. Most assays distinguish the two because their balance reflects redox conditions. The names are not interchangeable.
It is synthesized in the body from amino acids, so it is not classified as an essential dietary nutrient for most people. Dietary and supplemental forms are studied for their effects on tissue levels and health markers. Evidence varies by population and outcome.
The phrase highlights its high intracellular concentration and its role in several antioxidant and detoxification reactions. It is not the only antioxidant, and the term can oversimplify its functions. Scientific descriptions usually specify the pathway or enzyme involved.
It is a tripeptide rather than a full protein. Proteins generally contain many amino acids joined by alpha-peptide bonds, while glutathione has three residues and an unusual gamma-glutamyl linkage. That structure affects how enzymes recognize and break it down.