GSH raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-02-09. 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.
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 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.
| 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 |
=== Iron chelation === Multiple blood transfusions lead to severe iron overload, as the body eventually breaks down the hemoglobin in donated cells. This releases iron which it is unable to excrete. Iron overload may be treated by chelation therapy with the medications deferoxamine, deferiprone, or deferasirox. Deferoxamine is only effective as a daily injection, complicating its long-term use. Adverse effects include primary skin reactions around the injection site and hearing loss. Deferasirox and deferiprone are both oral medications, whose common side effects include nausea, vomiting and diarrhea.
Epothilones are a class of potential cancer drugs. Like taxanes, they prevent cancer cells from dividing by interfering with tubulin, but in early trials, epothilones have better efficacy and milder adverse effects than taxanes. Epothilones were originally identified as metabolites produced by the soil-dwelling myxobacterium Sorangium cellulosum. As of September 2008, epothilones A to F have been identified and characterized. Early studies in cancer cell lines and human cancer patients indicate superior efficacy to the taxanes. Their mechanism of action is similar, but their chemical structure is simpler. Due to their better water solubility, cremophors (solubilizing agents used for paclitaxel which can affect cardiac function and cause severe hypersensitivity) are not needed. Endotoxin-like properties known from paclitaxel, like activation of macrophages synthesizing inflammatory cytokines and nitric oxide, are not observed for epothilone B.
−O2CC(O)CH2CO2− ⇌ −O2CC(O−)CHCO2− + H+, pKa = 13.03 The enol forms of oxaloacetic acid are particularly stable. Keto-enol tautomerization is catalyzed by the enzyme oxaloacetate tautomerase. trans-Enol-oxaloacetate also appears when tartrate is the substrate for fumarase.
In 1952, couple and amateur ethnomycologists R. Gordon Wasson and Valentina Wasson learned of the ritual use of hallucinogenic mushrooms in the 16th century in Mexico from the published work of Schultes. They made several trips to Mexico in search of the mushrooms. In mid-1955, the Wassons participated in a mushroom ceremony with Mazatec curandera Maria Sabina in Huautla de Jiménez, Oaxaca, Mexico. Gordon Wasson published his experience in an article for Life magazine titled "Seeking the Magic Mushroom" in 1957, while Valentina Wasson published her experience as "I Ate the Sacred Mushroom" in This Week magazine the same year. Later in 1957, a second expedition was made by the Wassons to Mexico with French mycologist Roger Heim. Heim identified several of the mushrooms as belonging to the genus Psilocybe. They collected samples of the mushrooms and Heim sent a sample to Hofmann. Hofmann identified psilocybin as the active constituent in 1958 and developed a chemical synthesis for it. Sandoz Pharmaceuticals began distributing tablets of psilocybin under the brand name Indocybin in 1960. French scientists Césaire Phisalix and Gabriel Bertrand isolated bufotenin from Bufo toads in 1893 and named it. The compound was first isolated to purity by Austrian chemist Hans Handovsky in 1920. Clinical studies assessed the effects of bufotenin and were published starting in 1956. However, the findings of these studies were conflicting, and bufotenin developed a long-standing reputation of being inactive and toxic.
=== Neonates === Neonatal red cell transfusion, and when it is appropriate depends on: the gestational age of the baby; how long since the baby had been born; and also on whether the baby is well or ill.
Sources: en.wikipedia.org
== Further reading == Duckworth WC (August 1988). "Insulin degradation: mechanisms, products, and significance". Endocrine Reviews. 9 (3): 319–45. doi:10.1210/edrv-9-3-319. PMID 3061785. Affholter JA, Hsieh CL, Francke U, Roth RA (August 1990). "Insulin-degrading enzyme: stable expression of the human complementary DNA, characterization of its protein product, and chromosomal mapping of the human and mouse genes". Molecular Endocrinology. 4 (8): 1125–35. doi:10.1210/mend-4-8-1125. PMID 2293021. Duckworth WC, Hamel FG, Bennett R, Ryan MP, Roth RA (February 1990). "Human red blood cell insulin-degrading enzyme and rat skeletal muscle insulin protease share antigenic sites and generate identical products from insulin". The Journal of Biological Chemistry. 265 (5): 2984–7. doi:10.1016/S0021-9258(19)39898-9. PMID 1689296. Kuo WL, Gehm BD, Rosner MR (October 1990). "Cloning and expression of the cDNA for a Drosophila insulin-degrading enzyme". Molecular Endocrinology. 4 (10): 1580–91. doi:10.1210/mend-4-10-1580. PMID 2126597. Ding L, Becker AB, Suzuki A, Roth RA (February 1992). "Comparison of the enzymatic and biochemical properties of human insulin-degrading enzyme and Escherichia coli protease III". The Journal of Biological Chemistry. 267 (4): 2414–20. doi:10.1016/S0021-9258(18)45895-4. PMID 1733942. Mukherjee A, Song E, Kihiko-Ehmann M, Goodman JP, Pyrek JS, Estus S, et al. (December 2000). "Insulysin hydrolyzes amyloid beta peptides to products that are neither neurotoxic nor deposit on amyloid plaques". The Journal of Neuroscience. 20 (23): 8745–8749.
=== Animal health === In livestock, cattle and sheep commonly show indications when they are copper deficient. Swayback, a sheep disease associated with copper deficiency, imposes enormous costs on farmers worldwide, particularly in Europe, North America, and many tropical countries. For pigs, copper has been shown to be a growth promoter.
=== Environment === Boosting natural resource efficiency is the "single most important need for a sustainable food future," according to the World Resource Institute. As mentioned in the on-farm efficiency section, precision farming, including variable rate nutrient application, variable rate irrigation, machine guidance, and variable rate planting/seeding, could minimize use of agricultural inputs for a given yield. This could mitigate resource waste and negative environmental externalities, like greenhouse gas (GHG) emissions, soil erosion, and fertilizer runoff. For example, Katalin et al. 2014 estimate that switching to precision weed management could save up to 30,000 tons of pesticide in the EU-25 countries. González-Dugo et al. 2013 found that precision irrigation of a citrus orchard could reduce water use by 25 percent while maintaining a constant yield. Basso et al. 2012 demonstrated that variable-rate application of fertilizer can reduce nitrogen application and leaching without affecting yield and net return. However, precision agriculture could also accelerate farms' depletion of natural resources because of a rebound effect; increasing input efficiency does not necessarily lead to resource conservation.
=== Role in neural development === Laminin-111 is a major substrate along which nerve axons will grow, both in vivo and in vitro. For example, it lays down a path that developing retinal ganglion cells follow on their way from the retina to the tectum. It is also often used as a substrate in cell culture experiments. The presence of laminin-111 can influence how the growth cone responds to other cues. For example, growth cones are repelled by netrin when grown on laminin-111 but are attracted to netrin when grown on fibronectin. This effect of laminin-111 probably occurs through a lowering of intracellular cyclic AMP.
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.
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.