This is a working overview of glutathione, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-05-15 and is reviewed periodically as new material appears.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione | Tripeptide of glutamate, cysteine, and glycine |
| Reduced form | GSH | Dominant intracellular thiol |
| Oxidized form | GSSG | Disulfide-linked dimer |
| Molar mass | 307.32 g/mol | For reduced glutathione |
| Functional motif | Gamma-glutamyl-cysteinyl-glycine | Gamma linkage resists many peptidases |
Interpreting glutathione measurements requires attention to pre-analytical variables. The GSSG concentration in a sample can rise artificially during storage or processing, making the GSH/GSSG ratio unreliable if not controlled. Reference ranges vary by specimen type, assay, and population, so comparisons across studies are difficult. Plasma glutathione is low and sensitive to hemolysis, while whole blood reflects primarily erythrocyte content. Many studies measure total glutathione rather than the reduced and oxidized forms separately, which limits conclusions about redox status.
Accurate measurement of glutathione begins with careful sample handling. Because GSH oxidizes rapidly to GSSG, samples must be processed quickly or frozen immediately. Acid precipitation with metaphosphoric acid or perchloric acid is common; it lowers pH, precipitates proteins, and helps preserve the reduced form. Chelating agents such as EDTA can limit metal-catalyzed oxidation. For whole blood, hemolysis releases glutathione from erythrocytes, so plasma and serum values differ substantially from whole blood values.
Several analytical methods can quantify glutathione, including high-performance liquid chromatography (HPLC) with UV or fluorescence detection for separating GSH and GSSG. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) offers higher specificity and sensitivity, often detecting nanomolar concentrations. The enzymatic recycling assay, often called the Tietze method, measures total glutathione by coupling reduction of GSSG to a colorimetric or fluorometric readout. Capillary electrophoresis and electrochemical detection are also used in specialized laboratories. Each method has distinct advantages and limitations regarding throughput, cost, and susceptibility to interference.
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.
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.
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.
Biosynthesis occurs in two ATP-dependent steps. The enzyme glutamate-cysteine ligase joins glutamate and cysteine, forming gamma-glutamylcysteine; glutathione synthetase then adds glycine to produce the complete tripeptide. Because the peptide bond from glutamate uses the gamma-carboxyl group, glutathione resists digestion by many ordinary peptidases. Tissues vary in synthesis capacity, and the liver generally contains high concentrations relative to many other organs. This uneven distribution contributes to organ-specific differences in redox buffering and affects how experimental results are interpreted across tissue types.
Glutathione participates in detoxification reactions, amino acid transport, and the maintenance of protein thiols. It serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. In research literature, altered glutathione status appears in studies of aging, infection, metabolic stress, and environmental exposure. Whether low glutathione is a cause, consequence, or marker of such conditions often remains unresolved. Direct measurement in blood or tissue provides a snapshot, but results depend on sample handling, timing, and the method used.
cleavage 1. The physical separation of a dividing parent cell into multiple individual daughter cells. 2. In embryology, the series of mitotic divisions by which a fertilized ovum is divided, without an accompanying overall change in size, into a ball of smaller cells constituting the early embryo.
The Hungarian Revolution of 1956 was a spontaneous nationwide revolt by democratic socialists against the Marxist–Leninist government of the People's Republic of Hungary and its policies of repression, lasting from 23 October until 10 November 1956. Soviet leader Nikita Khrushchev's denunciation of the excesses of Stalin's regime during the 20th Congress of the Communist Party of the Soviet Union that same year as well as the revolt in Hungary produced ideological fractures and disagreements within the democratic communist and socialist parties of Western Europe. A split ensued within the Italian Communist Party (PCI), with most ordinary members and the PCI leadership, including Giorgio Napolitano and Palmiro Togliatti, regarding the Hungarian insurgents as counter-revolutionaries as reported in l'Unità, the official PCI newspaper. Giuseppe Di Vittorio, General Secretary of the Italian General Confederation of Labour, repudiated the leadership position, as did the prominent party members Loris Fortuna, Antonio Giolitti and many other influential communist intellectuals who later were expelled or left the party. Pietro Nenni, the national secretary of the Italian Socialist Party, a close ally of the PCI, opposed the Soviet intervention as well. Napolitano, elected in 2006 as President of the Italian Republic, wrote in his 2005 political autobiography that he regretted his justification of Soviet action in Hungary and that at the time he believed in party unity and the international leadership of Soviet communism.
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== Further reading == Kallweit MS, Kallweit NP, Kallweit U (29 November 2023). "Pharmacological Treatments of Sleep–Wake Disorders: Update 2023". Clinical and Translational Neuroscience. 7 (4): 42. doi:10.3390/ctn7040042. hdl:20.500.12512/242676. ISSN 2514-183X. Kornum BR, Breum AW, Mincikiewicz Z, Knudsen-Heier S (July 2026). "Therapeutic potential of targeting the orexin (hypocretin) system in sleep disorders". Nat Rev Endocrinol. doi:10.1038/s41574-026-01277-2. PMID 42533134.
Sources: en.wikipedia.org
Microfluidic liquid-liquid extraction has shown to be advantageous in numerous applications such as pharmacokinetic drug studies where only small cell numbers are needed, and in additional studies where smaller reagent volumes are required. Droplet-based microfluidics can also be used for chemical phase transfer reactions. An early example was the synthesis of azo dyes in nanoliter fluid segments using a double injector chip device.
VOCs are also found in hospital and health care environments. In these settings, these chemicals are widely used for cleaning, disinfection, and hygiene of the different areas. Thus, health professionals such as nurses, doctors, sanitation staff, etc., may present with adverse health effects such as asthma; however, further evaluation is required to determine the exact levels and determinants that influence the exposure to these compounds. Concentration levels of individual VOCs such as halogenated and aromatic hydrocarbons vary substantially between areas of the same hospital. Generally, ethanol, isopropanol, ether, and acetone are the main compounds in the interior of the site. Following the same line, in a study conducted in the United States, it was established that nursing assistants are the most exposed to compounds such as ethanol, while medical equipment preparers are most exposed to 2-propanol. In relation to exposure to VOCs by cleaning and hygiene personnel, a study conducted in 4 hospitals in the United States established that sterilization and disinfection workers are linked to exposures to d-limonene and 2-propanol, while those responsible for cleaning with chlorine-containing products are more likely to have higher levels of exposure to α-pinene and chloroform.
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Sources: en.wikipedia.org
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.
Reduced glutathione, GSH, can donate electrons and become oxidized to GSSG. The balance between these forms reflects the cell's redox environment. A shift toward GSSG is commonly interpreted as evidence of oxidative stress, though the ratio can vary by tissue and method.
Glutathione occurs in nearly all cell types, with notable amounts in the liver. It is also present in the lungs, kidneys, and red blood cells. Concentrations differ among tissues and change with age, diet, and disease states.
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.