The short version of thiol group fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-04-04. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione | Reduced form is abbreviated GSH |
| Chemical class | Tripeptide | Composed of glutamate, cysteine, and glycine |
| Molar mass | 307.32 g/mol | For reduced glutathione |
| CAS Registry Number | 70-18-8 | For reduced L-glutathione |
| Appearance | White crystalline powder | Typical solid reference material |
Cells synthesize glutathione through two ATP-dependent enzymatic steps. The first step combines glutamate and cysteine to form gamma-glutamylcysteine, catalyzed by glutamate-cysteine ligase. The second step adds glycine, producing the complete tripeptide, catalyzed by glutathione synthetase. Glutathione itself can inhibit the first enzyme, providing negative feedback when levels are high. Because cysteine is often limiting, its availability influences how quickly the pathway proceeds. These reactions occur in the cytosol, and the resulting glutathione can be distributed to other compartments.
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a small tripeptide composed of glutamate, cysteine, and glycine, with the unusual gamma-glutamyl linkage between glutamate and cysteine. Its cysteine thiol group makes it a major non-enzymatic antioxidant in cells. The reduced form, GSH, predominates in most intracellular compartments, while the oxidized disulfide form, GSSG, is produced when GSH reduces reactive oxygen species. Intracellular concentrations often reach millimolar levels, whereas plasma concentrations are much lower, typically in the low micromolar range. This gradient reflects active synthesis, transport, and consumption rather than passive distribution.
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.
In its reduced form, glutathione carries a sulfhydryl group that can donate electrons. This property lets it act as a major cellular antioxidant and redox buffer. Glutathione peroxidase uses it to reduce hydrogen peroxide and lipid peroxides, while glutathione reductase regenerates the reduced form using NADPH. The ratio of reduced glutathione to glutathione disulfide is widely used as an indicator of oxidative stress, though the ratio changes with compartment, cell type, and sample handling. Oxidized glutathione can also form mixed disulfides with proteins, affecting their activity.
Glutathione supports detoxification by conjugating reactive electrophiles through glutathione S-transferases. The resulting conjugates are processed and exported, often after further metabolism. It also stores cysteine, transports amino acids across membranes through the gamma-glutamyl cycle, and assists in the maturation of iron-sulfur clusters and some prostaglandins. In plants, animals, and many microbes, the molecule appears in similar roles, but concentrations vary enormously between tissues. Liver, kidney, and red blood cells tend to contain high amounts, while blood plasma contains much less.
Glutathione is a small tripeptide built from glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group, a linkage that resists ordinary peptidases. Cells make it in two ATP-dependent steps: gamma-glutamylcysteine synthetase joins glutamate and cysteine, then glutathione synthetase adds glycine. The pathway is feedback-inhibited by glutathione itself, so intracellular levels tend to stay within a narrow range. Because cysteine is often limiting, sulfur amino acid supply influences how much glutathione a cell can produce.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It contains an unusual gamma-glutamyl bond between glutamate and cysteine, which resists cleavage by many peptidases. The reduced form, GSH, carries a thiol group on cysteine and is the dominant intracellular form in most cells. Its structure allows it to participate in redox reactions and to serve as a sulfur donor. The oxidized form, GSSG, consists of two GSH molecules joined by a disulfide bond.
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.
Acquired dysfibrinogenemia is a rare disorder in which circulating fibrinogen is composed at least in part of a dysfunctional fibrinogen due to various acquired diseases. One well-studied cause of the disorder is severe liver disease including hepatoma, chronic active hepatitis, cirrhosis, and jaundice due to biliary tract obstruction. The diseased liver synthesizes a fibrinogen which has a normally functional amino acid sequence but is incorrectly glycosylated (i.e. has a wrong amount of sugar residues) added to it during its passage through the Golgi. The incorrectly glycosylated fibrinogen is dysfunctional and may cause pathological episodes of bleeding and/or blood clotting. Other, less well understood, causes are plasma cell dyscrasias and autoimmune disorders in which a circulating abnormal immunoglobulin or other protein interferes with fibrinogen function, and rare cases of cancer and medication (isotretinoin, glucocorticoids, and antileukemic drugs) toxicities.
== Areas of application == This technique can be utilized in the aviation industry. As in principle, prepreg has the potential to be processed batch sizes. Despite fiber glass having high applicability in aircraft specifically small aircraft motors, carbon fiber is employed in this type of industry at a higher rate, and the demand for it is increasing. For example, the characterization of Airbus A380 is handled by means of a mass fraction. This mass fraction is about 20%, and the Airbus A350XWB by a mass fraction of about 50% of carbon fiber prepregs. Carbon fiber prepregs have been used in the airfoils of the Airbus fleet for more than 20 years. The usage of prepreg in automotive industry is used at relatively limited quantities in comparison with other techniques like automated tape lay-up and automated fiber placement. The main reason behind this is the relative high cost of prepreg fibers as well as the compounds used in molds. Example of such materials are bulk moulding compound (BMC) or sheet moulding compound (SMC). This material is used to make the cockpit doors on the Airbus A320. This material provides bulletproofness.
== Literature == Kitagaki H (2021). "Medical Application of Substances Derived from Non-Pathogenic Fungi and -Containing". Journal of Fungi. 7 (4): 4. doi:10.3390/jof7040243. PMC 8063943. PMID 33804991. J. E. Smith (6 December 2012). Aspergillus. Springer US. pp. 46ff. ISBN 978-1-4615-2411-3.
Chemical intervention-related results First senolytics discovered using artificial intelligence: Teams from the University of Edinburgh and the Massachusetts Institute of Technology independently report the discovery of senolytics using artificial intelligence for screening large chemical libraries. The works reported compounds of comparable efficacy and increased potency than other known senolytics. A study identifies low levels of taurine, which declines with age, as a driver of the aging process and suggests that taurine supplements may increase lifespan. Ora Biomedical announces the "million molecule challenge", an effort to assess 1 million potential longevity interventions within five years using artificial intelligence. A study suggests chemical alternatives to age reversal via Yamanaka factors gene therapy are feasible via early in vitro fibroblasts data. These results have not yet been validated in an animal and via more reliable "improvements in age-related health metrics or lifespan". Subcutaneous administration of longevity factor α-klotho enhanced cognition in old rhesus macaques. In a paywalled review, the authors of a heavily cited paper on the hallmarks of aging update the set of proposed hallmarks after a decade. A review with overlapping authors merge or link various hallmarks of cancer with those of aging. A study concludes that retroviruses in the human genomes can become awakened from dormant states and, in senescent cells and aged tissue, contribute to aging which can be blocked by neutralizing antibodies, resulting in improved function.
== Structure == The 3D structure of human serum albumin has been determined by X-ray crystallography to a resolution of 2.5 ångströms (250 pm). Albumin is a 65–70kDa protein. Albumin comprises three homologous domains that assemble to form a heart-shaped protein. Each domain is a product of two subdomains that possess common structural motifs. The principal regions of ligand binding to human serum albumin are located in hydrophobic cavities in subdomains IIA and IIIA, which exhibit similar chemistry. Structurally, the serum albumins are similar, each domain containing five or six internal disulfide bonds.
Sources: en.wikipedia.org
=== Other applications === Easton-Bell Sports, Inc. have been in partnership with Zyvex Performance Materials, using CNT technology in a number of their bicycle components – including flat and riser handlebars, cranks, forks, seatposts, stems and aero bars. Amroy Europe Oy manufactures Hybtonite carbon nano-epoxy resins where carbon nanotubes have been chemically activated to bond to epoxy, resulting in a composite material that is 20% to 30% stronger than other composite materials. It has been used for wind turbines, marine paints and a variety of sports gear such as skis, ice hockey sticks, baseball bats, hunting arrows, and surfboards. Surrey NanoSystems synthesizes carbon nanotubes to create vantablack ultra-absorptive black paint. "Gecko tape" (also called "nano tape") is often commercially sold as double-sided adhesive tape. It can be used to hang lightweight items such as pictures and decorative items on smooth walls without punching holes in the wall. The carbon nanotube arrays comprising the synthetic setae leave no residue after removal and can stay sticky in extreme temperatures. Tips for atomic force microscope probes. One proposed use of carbon nanotubes is in paper batteries, developed in 2007 by researchers at Rensselaer Polytechnic Institute. Another highly speculative proposed use in the field of space technologies is to produce high-tensile carbon cables required by a space elevator.
Russian forces captured the village of Tymofiivka in Donetsk Oblast. Russia launched a massive drone attack on Kyiv, with Ukrainian forces claiming to have intercepted 40 drones. Russian forces claimed to have intercepted a Neptune-MD missile and 19 drones over Belgorod, Bryansk, Kursk, Kaluga, and Rostov Oblasts as well as in Crimea. The acting governor of Kursk, Alexei Smirnov, said that an “unidentified facility” caught fire after midnight. Ukraine claimed it was a “storage facility for weapons and military equipment”. In Belgorod, commercial and residential properties caught fire. No casualties were reported in the attacks. The Belgorod governor also claimed Ukrainian forces fired six cluster shells at buildings. The Freedom of Russia Legion announced its withdrawal from the Irpin Declaration, but said that it would continue to fight Kremlin forces. A Russian Mi-8 helicopter was shot down over occupied Donetsk, speculated to be either by a Ukrainian FPV drone or by Russian fire. Ukraine received its first F-16s. Austrian military analyst Col. Markus Reisner, citing a recent military study, estimated that Russian forces had lost between 500,000 and 750,000 soldiers killed and wounded in action, with "perhaps" 100,000 to 150,000 Russian soldiers killed. He also said that Ukraine had "suffered very heavy losses".
Per CLIA, each specific laboratory system, assay, examination is graded for level of complexity by assigning scores of 1, 2, or 3 for each of the following seven criteria. A score of 1 is the lowest level of complexity, and a score of 3 is the highest. Score 2 is assigned when the characteristics for a particular test are intermediate between the descriptions listed for scores of 1 and 3. Criteria for categorization:
=== Neonatal abstinence === Buprenorphine has been used in the treatment of the neonatal abstinence syndrome, a condition in which newborns exposed to opioids during pregnancy demonstrate signs of withdrawal. In the United States, use currently is limited to infants enrolled in a clinical trial conducted under an FDA-approved investigational new drug (IND) application. Preliminary research suggests that buprenorphine is associated with shorter time in hospital for neonates, compared to methadone. An ethanolic formulation used in neonates is stable at room temperature for at least 30 days.
Sources: en.wikipedia.org
Directly dissolving SO3 in water, called the "wet sulfuric acid process", is rarely practiced because the reaction is extremely exothermic, resulting in a hot aerosol of sulfuric acid that requires condensation and separation. In the first step, sulfur is burned to produce sulfur dioxide:
Weapons supplied to SWALA between 1962 and 1966 included PPSh-41 submachine guns, SKS carbines, and TT-33 pistols, which were well-suited to the insurgents' unconventional warfare strategy. Despite its burgeoning relationship with SWAPO, the Soviet Union did not regard Southern Africa as a major strategic priority in the mid 1960s, due to its preoccupation elsewhere on the continent and in the Middle East. Nevertheless, the perception of South Africa as a regional Western ally and a bastion of neocolonialism helped fuel Soviet backing for the nationalist movement. Moscow also approved of SWAPO's decision to adopt guerrilla warfare because it was not optimistic about any solution to the South West Africa problem short of revolutionary struggle. This was in marked contrast to Western governments, which opposed the formation of SWALA and turned down the latter's requests for military aid.
negative control Also negative regulation. The inhibition or deactivation of some biological process caused by the presence of a specific molecular entity (e.g. a repressor), in the absence of which the process is not inhibited and thus can proceed normally. In gene regulation, for example, a repressor may bind to an operator upstream from a coding sequence and prevent access by transcription factors and/or RNA polymerase, thereby blocking the gene's transcription. This is contrasted with positive control, in which the presence of an inducer is necessary to switch on transcription.
Sources: en.wikipedia.org
GSH is the reduced thiol form, while GSSG is the disulfide-linked oxidized dimer. The GSH:GSSG ratio is used as a redox indicator, though the ratio can vary with sample handling and cell type.
Glutathione is present in many foods, including meats, poultry, fish, some vegetables, and fruits. Cooking, storage, and digestion affect the amounts available for absorption.
Yes, both enzymatic steps in glutathione synthesis consume ATP. The first step, catalyzed by glutamate-cysteine ligase, is usually rate-limiting.
Glutathione is a tripeptide made from glutamate, cysteine, and glycine. Its cysteine residue provides a thiol group that is central to its redox activity. The glutamate-cysteine bond forms through the gamma-carboxyl group of glutamate.