If you have been reading about glutathione and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Updated 2025-12-03. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced glutathione (GSH) |
| Molar mass | 307.32 g/mol | Oxidized dimer GSSG is 612.63 g/mol |
| Appearance | White to off-white crystalline powder | Typical purified solid |
| Solubility | Freely soluble in water; practically insoluble in ethanol | Polarity reflects multiple ionizable groups |
| Common synonyms | GSH; L-glutathione; γ-glutamylcysteinylglycine | 'Reduced' distinguishes it from GSSG |
Laboratory measurement of glutathione typically starts with rapid acid extraction to prevent oxidation and enzymatic degradation. Common methods include enzymatic recycling assays, high-performance liquid chromatography, and liquid chromatography coupled with mass spectrometry. The recycling assay uses glutathione reductase and a thiol-reactive colorimetric or fluorescent reagent, measuring total glutathione after converting disulfide forms. Chromatographic methods can separate reduced and oxidized forms, which helps when the redox ratio is the target. Choice of method affects sensitivity, specificity, and the amount of sample needed.
Samples for glutathione analysis require careful handling because the compound oxidizes readily and can be consumed by enzymes after collection. Blood is often treated with acid or thiol-blocking agents soon after draw, and plasma should be separated quickly from red blood cells. Tissues are usually snap-frozen or extracted immediately. Aqueous solutions of glutathione are less stable than dry powder and degrade faster at neutral or alkaline pH, in light, or with dissolved oxygen. Repeated freeze-thaw cycles also reduce reliability.
Quality control for glutathione materials checks identity, assay, purity, water content, and disulfide content. Commercial products vary from research-grade powder to dietary supplements, and labels may not distinguish reduced from oxidized forms. In the United States, oral glutathione is commonly sold as a dietary supplement rather than an approved drug, while injectable forms fall under different rules and may require a prescription. Regulatory status differs by country. Analytical certificates, when available, help verify what a material contains, but independent testing remains important for interpretation.
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.
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.
target site The site or locus upon another molecule at which a protein performs a particular biochemical activity; e.g. the nucleotide motif at which a restriction endonuclease cleaves a DNA molecule, often but not necessarily the same as the enzyme's recognition site (i.e. a restriction enzyme may recognize one motif, known as a restriction site, and cleave at another).
DWNT synthesis on the gram-scale by the CCVD technique was first proposed in 2003 from the selective reduction of oxide solutions in methane and hydrogen. The telescopic motion ability of inner shells, allowing them to act as low-friction, low-wear nanobearings and nanosprings, may make them a desirable material in nanoelectromechanical systems (NEMS) . The retraction force that occurs to telescopic motion is caused by the Lennard-Jones interaction between shells, and its value is about 1.5 nN.
== Computational approach == The basic idea behind reverse vaccinology is that an entire pathogenic genome can be screened using bioinformatics approaches to find genes. Some traits that the genes are monitored for, may indicate antigenicity and include genes that code for proteins with extracellular localization, signal peptides & B cell epitopes. Those genes are filtered for desirable attributes that would make good vaccine targets such as outer membrane proteins. Once the candidates are identified, they are produced synthetically and are screened in animal models of the infection.
The draining of the Qurna Marshes was an irrigation project in Iraq during and immediately after the war, to drain a large area of marshes in the Tigris–Euphrates river system. Formerly covering an area of around 3,000 km2 (1,200 sq mi), the large complex of wetlands were nearly emptied of water, and the local Shi'ite population relocated, following the war and 1991 uprisings. By 2000, the United Nations Environment Programme estimated that 90% of the marshlands had disappeared, causing desertification of over 7,500 square miles (19,000 km2). The draining occurred in Iraq and to a smaller degree in Iran between the 1950s and 1990s to clear large areas of the marshes. Formerly covering an area of around 20,000 km2 (7,700 sq mi), the large complex of wetlands was 90% drained before the 2003 Invasion of Iraq. The marshes are typically divided into three main sub-marshes, the Hawizeh, Central, and Hammar Marshes and all three were drained at different times for different reasons. Initial draining of the Central Marshes was intended to reclaim land for agriculture but later all three marshes would become a tool of war and revenge. Many international organizations such as the UN Human Rights Commission, the Islamic Supreme Council of Iraq, the Wetlands International, and Middle East Watch have described the project as a political attempt to force the Marsh Arabs out of the area through water diversion tactics.
Sources: en.wikipedia.org
Lactobacillus delbrueckii subsp. lactis is a subspecies of Lactobacillus delbrueckii that is generally used to measure the amount of cobalamin in food. Its growth rate is proportional to the amount of cobalamin in the growth medium. However, lactis has been demonstrated to have the option to utilize pseudocobalamin, which is inactive for humans, as well as "alkali-resistant factors" (deoxyribosides and deoxynucleotides), leading to an overestimation of the amount of cobalamine in food. As such, new methods using HPTLC or LC-MS/MS have also been developed.
Directed by Sheila Hayman, made by Uden Associates 8 November Rebuilding Berlin, how German telecommunication and electrical engineers found great difficulty in connecting the infrastructure and technology of East and West Berlin, which were largely totally incompatible, and why the two technological systems were so different; East and West Germany were founded in 1953; the trains in East (Deutsche Reichsbahn or DR) and West Germany ran on electric motors that worked in opposite ways; Erich Kratky of Berliner Verkehrsbetriebe (former West Berlin Public Transport) and how East Berlin drivers had 60% of those in West Berlin; Mahlow station, on the S2 line on the Berlin S-Bahn, was completely rebuilt in 1991, opening on 31 August 1992; before 1989, West Berlin could not connect to any neighbouring electrical power networks, so had to make all of its own power itself, by nine power stations; in 1992 West Berlin could not make enough electrical power;Jürgen Beyer of the East Berlin Electricity Board; in 1992 East and West Germany could not connect their electricity systems together; Klaus Krämer of the West Berlin Electricity Board, and how East German load frequency control (LFC) was not good enough for West Germany; East German power stations were polluting; Müggelsee in East Berlin; East Berlin had natural gas - from Russia - but West Berlin did not have natural gas, and had to produce its own gas from processing, and there were many more gas leaks in East Berlin, run by the Berlin Gas Board, and British Gas plc was installing most of the new plastic gas mains in East Berlin; one fifth of housing in East Berlin was uninhabitable, due to lack of renovation and unsafe electrical wiring; much housing in East Berlin did not have any bathrooms; the post system in East Berlin was three times slower than West Berlin, as it was all sorted by hand, and mail hand to be sent in standard envelopes only, in East Germany - the two post systems were incompatible, and East and West Germany had totally different postcode systems, although both had four digits, so a letter was put in front of each Deutsche Post postcode, to show if it was an East or West German postcode; in 1952, telephone connections between East and West Germany were stopped, but four lines were installed in 1972; the East German telephone exchanges were all mechanical, and could not transmit any digital communications; one in ten people in East Berlin had a phone - telecommunications in East Berlin were hopeless and expensive; in 1992 Deutsche Telekom connected East and West Berlin, and the price would be a local call, not the price of an international call, under the phrase Wir schaffen Verbingdungen; not only were East German telecommunications often impossible, but the Stasi secret police were listening in to most calls; Rudolf Reichel of the former East German Economic Institute; science research in East Germany had been greatly restricted; Volker Hassemer; East Germans viewed West Germans as selfish, and West Germans viewed East Germans as backward. Narrated by Su-Lin Looi, directed by Cosima Dannoritzer, produced by Karl Sabbagh, made by Skyscraper Productions 15 November 21st Century Jet, how the Boeing 777 moved from the drawing board to manufacture in 1992, with the innovative new method called CATIA; the Boeing 777 was the largest jet aircraft to have been developed mostly by computer, with assembly beginning in January 1993; there were 10,000 people in the 777 programme, who met the managers in a weekly meeting; meeting the needs of Robert Crandall of American Airlines, and competition from the new Airbus A340; parts of the tail were built in Australia; the nose cone and flaps were made in Italy; the landing gear was made in Canada, the US, and France; parts of the wing ribs and passenger doors were made in Japan; the nose landing gear door was made in Belfast; some of the electronics was made in England; there were about 230 design teams, from different manufacturers; the CATIA system was a digital mockup; Thomas Gaffney, head of passenger doors; Henry Shomber, one of the chief engineers; John Roundhill, a chief project engineer; United Airlines placed the first order, which started the project; Al Tyler of Aerospace Technologies of Australia (ASTA), who made the 777 rudder - the company became Boeing Australia; John King, Baron King of Wartnaby of British Airways visits to look at legroom for the new 777. Narrated by Simon Prebble, directed by Karl Sabbagh, made by Skyscraper Productions 22 November The Puzzle of HIV, scientists after ten years did not understand how HIV worked; immunologists Anthony Fauci and Max Essex; Angus Dalgleish of St George's, University of London; virologist Stephen S. Morse, and the origination of viruses, and how most pandemics originated in China; Stella Knight of the MRC, and dendritic cells, researched by Brigid Balfour; French immunologist Jean-Claude Ameisen of the Pasteur Institute of Lille; virologist Jonas Salk; Claude Nicolau, and the CD4 glycoprotein. Narrated by Scottish actress Sandra Clark, directed by Nigel Maslin, produced by Chris Haws, made by InCA Productions 29 November The Alpha Link, much of medical understanding of radiation protection and health comes from what occurred in Japan in August 1945. Martin Gardner (1940–93), an epidemiologist, and Professor of Medical Statistics at the University of Southampton, thought that health was affected by working in a nuclear power station, which the British nuclear industry vehemently would not believe. Directed by Vivienne King, made by Box Productions 6 December Toying with the Future, about electronic children's toys, visiting Ocean Software in Manchester; Brian Sutton-Smith of the University of Pennsylvania, and how toys were small replicas of large world events; Eugene F. Provenzo of the University of Miami and how the culture of childhood began in the early 1700s, and how German Friedrich Fröbel developed educational toys in the early 1800s, but it often lacked fun; Meccano Ltd sets, developed by Frank Hornby, launching the international Meccano Guild network of children's mechanical clubs in 1919, publicised by the Meccano Magazine; Richard Gregory, neuropsychologist at the University of Bristol, and his Exploratory Hands-on Science Centre, which closed in 1999, replaced by We the Curious in 2000; toy designer Patrick Rylands; Gary Bracey of Ocean Software; Keith Tinman, computer game musician; Elizabeth Curran of GameTek; Ocean Software designers Ray Coffey, James Higgins and Dawn Drake. Directed by Christopher Rawlence, produced by Debra Hauer, made by Rawlence Hauer Productions 13 December The Elements, a repeat of the 20 October 1991 episode 20 December E.T. Please Phone Earth, about the SETI Institute, with Prof Philip Morrison, a professor of physics at MIT, who played a starring if not dangerous role in the Manhattan Project; Jill Tarter at the Hat Creek Radio Observatory in California; Dr John Billingham, a British medical doctor at the Ames Research Center in California; Prof Antony Hewish of the University of Cambridge, who discovered pulsars in 1967; Frank Drake, and his work at the National Radio Astronomy Observatory in Green Bank, West Virginia; Barney Oliver of SETI; David Blair of the University of Western Australia; Paul Horowitz of Harvard University; the Ohio State University Radio Observatory (known as Big Ear) and its 1977 Wow! signal; Jack Cohen; chemist Stanley Miller and his 1953 experiment; blind SETI investigator Kent Cullers; and biologist Jared Diamond from UCLA. Jointly made with ABC of Australia, narrated by Heather Couper, directed by Richard Smith, produced by Stuart Carter, made by Pioneer Productions
=== Animal studies in vivo === An in vivo study in aging mice found that epitalon treatment significantly reduced the incidence of chromosomal aberrations, both for wild-type mice and for mice characterized by an accelerated aging phenotype, which is consistent with increases in telomere length. Another study in aging rats found that epitalon increased the activities of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and glutathione-S-transferase. Epitalon reduced the number of spontaneous tumors and the number of metastases in mice that did develop spontaneous tumors in an experiment on one-year-old female mice of the C3H/He inbred strain, and is speculated to have oncostatic and anti-metastatic properties. In a study of chickens subjected to neonatal hypophysectomy and subsequent maturation, epitalon promoted the recovery of the morphological structures of the thymus, as well as the structure and function of the thyroid gland. Epitalon appears to increase the proliferation of lymphocytes in the thymus, putatively increasing production of interferon gamma by T-cells. Another study in aging rats demonstrated extension of life span for rats subjected to constant illumination or to a natural light regimen typical of northern regions.
Sources: en.wikipedia.org
Osteogenesis imperfecta is a group of genetic disorders, all of which cause bone fragility. OI has high genetic heterogeneity, that is, many different genetic mutations lead to the same or similar sets of observable symptoms (phenotypes). The main causes for developing the disorder are a result of mutations in the COL1A1 and/or COL1A2 genes which are jointly responsible for the production of collagen type I. Approximately 90% of people with OI are heterozygous for mutations in either the COL1A1 or COL1A2 genes. There are several biological factors that are results of the dominant form of OI. These factors include: intracellular stress; abnormal tissue mineralization; abnormal cell-to-cell interactions; abnormal cell-matrix interactions; a compromised cell matrix structure; and, abnormal interaction between non-collagenous proteins and collagen. Previous research led to the belief that OI was an autosomal dominant disorder with few other variations in genomes. However, with the lowering of the cost of DNA sequencing in the wake of 2003's Human Genome Project, autosomal recessive forms of the disorder have been identified. Recessive forms of OI relate heavily to defects in the collagen chaperones responsible for the production of procollagen and the assembly of the related proteins. Examples of collagen chaperones that are defective in patients with recessive forms of OI include chaperone HSP47 (Cole-Carpenter syndrome) and FKBP65. Mutations in these chaperones result in an improper folding pattern in the collagen 1 proteins, which causes the recessive form of the disorder.
According to one review, an optimal dosing regimen is to administer it in one 1 gram dose, three times a day, since this ensures elevated plasma concentrations of HMB throughout the day; however, as of 2016 the best dosing regimen for muscle wasting conditions is still being investigated. Some branded products that contain HMB (i.e., certain formulations of Ensure and Juven) are medical foods that are intended to be used to provide nutritional support under the care of a doctor in individuals with muscle wasting due to HIV/AIDS or cancer, to promote wound healing following surgery or injury, or when otherwise recommended by a medical professional. Juven, a nutrition product which contains 3 grams of HMB-Ca, 14 grams of L-arginine, and 14 grams of L-glutamine per two servings, has been shown to improve lean body mass during clinical trials in individuals with AIDS and cancer, but not rheumatoid cachexia. Further research involving the treatment of cancer cachexia with Juven over a period of several months is required to adequately determine treatment efficacy.
== Contraindications and precautions == Patients with known hypersensitivity to Oprelvekin itself or any other ingredient. Patients with severe or decompensated heart failure should not be treated, because Oprelvekin may cause excessive fluid retention with edema and cardiac decompensation. Patients with compensated heart disease should be treated with caution and under permanent clinical supervision. Neumega is not indicated following myeloablative chemotherapy (increased likelihood of severe side-effects) and in pediatric patients. Renal impairment: Neumega is excreted renally. No differences of pharmakinetic parameters and clinical differences have been seen in mild to moderate impairment. Severe impairment has led to an increased number of patients with reduced hemoglobin due to dilutional anemia. Patients with severely disturbed renal function should be monitored very closely. The efficacy of Oprelvekin has not been systematically studied in patients receiving chemotherapy regimes of more than 5 days duration/each cycle or in those regimes containing agents that induce delayed thrombocytopenia (e.g. nitrosoureas, mitomycin C. Neumega should not be given in these cases.
Sources: en.wikipedia.org
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.
GSH is the reduced form with a free thiol group. GSSG is the oxidized disulfide dimer formed when two GSH molecules react. The GSH-to-GSSG ratio is used in research as one indicator of cellular redox conditions.
Yes, it is present in many animal and plant tissues, including meats, some vegetables, and fruits. Heat, storage, and processing can reduce its content, so measured amounts vary widely.
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.