The short version of GSSG fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2025-08-07. Anything still debated is marked as such rather than presented as settled.
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.
| Property | Value | Notes |
|---|---|---|
| Common analytical method | LC-MS/MS or HPLC | Separation of GSH and GSSG |
| Limit of detection | Nanomolar range | Method dependent |
| Typical sample storage | -80 °C | For biological matrices |
| Common reducing agent | TCEP or DTT | Prevents oxidation during processing |
| Common synonym | Gamma-glutamylcysteinylglycine | Systematic name |
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.
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.
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.
Creatine + ATP ⇌ creatine phosphate + ADP + H+ (this reaction is Mg2+-dependent) However, annelids (segmented worms) use a set of unique phosphagens; for example, earthworms use the compound lombricine. Phosphagens were discovered by Philip Eggleton and his wife Grace Eggleton.
== External links == NPR2+protein,+human at the U.S. National Library of Medicine Medical Subject Headings (MeSH) This article incorporates text from the United States National Library of Medicine, which is in the public domain.
== External links == "P2Y Receptors: P2Y11". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology. Archived from the original on 2016-03-03. Retrieved 2008-12-09. This article incorporates text from the United States National Library of Medicine, which is in the public domain.
These new RNA transcripts are then used to repeat the selection cycle many times, thus eventually producing a homogeneous pool of RNA aptamers capable of highly specific, high-affinity target binding.
Sources: en.wikipedia.org
The Sanger Institute About the 1958 Nobel Prize About the 1980 Nobel Prize Fred Sanger 2001 Video Documentary by The Vega Science Trust Portraits of Frederick Sanger at the National Portrait Gallery, London Frederick Sanger interviewed by Alan Macfarlane, 24 August 2007 (video), also available on Video on YouTube. Duration 57 minutes. Frederick Sanger archive collection – Wellcome Library finding aid for the digitised collection. Frederick Sanger on Nobelprize.org
=== Familia Presto series 1 (FA3; 1970) === From April 1970, the Presto nameplate was added into the entire Familia range, "Presto" means "quick" in Italian. Brand new overhead camshaft 1.3-litre TC engine also appeared, derived from the smaller 1.0-litre OHC engine already seen in the first generation Familia coupé. At the same time, the range received a light facelift including a chrome strip around the front grille. Unlike the pickup, the vans also used the "Familia Presto" name. Chassis codes are SPCV for the 1.0-litre and STBV for the 1.3-litre model, with power outputs as for the saloon/coupé. Standard and Deluxe versions were available, with the Deluxe also offering five-door bodywork. The Familia was exported as the "Mazda 1300", and replaced the previous generation 1200 model in most markets. In Finland, the Familia Presto was marketed as the "Mazda Marella." The saloon and coupé were updated in 1972 in Japan and in the autumn of 1973 for export market, but the pickup and wagon/van versions continued with little change. The vans and pickups actually soldiered on until 1978, by which time a wagon version of the succeeding FA4 Familia (323/GLC) had been introduced. The later pickup versions were also available in a long-wheelbase version, and still featured an 85 PS (63 kW) (SAE gross) version of the 1.3-litre TC engine, unaffected by the tighter Japanese emissions standards for passenger cars. The "1200" was offered in the United States in 1971 and again for the 1973 model year.
Stumpf (1919–2007) was an American biochemist at the University of California, Davis, known for work in the field of plant biochemistry. Member Natl. Acad. Sci. USA. Author, with Joe Neilands of Outlines of Enzyme Chemistry. Albert Szent-Györgyi (1893–1986). Hungarian biochemist at Woods Hole, Massachusetts, the first to isolate vitamin C. He discovered the components and reactions of the TCA cycle. Nobel Prize in Physiology or Medicine in 1937. Member Natl. Acad. Sci. USA.
Volume or capacity of data is often compared to works of literature or large collections of writing. Popular units include the Bible, the Encyclopædia Britannica, phone books, the complete works of Shakespeare, and the Library of Congress. When the Compact Disc began to be used as a data storage device as the CD-ROM, journalists often described the disc capacity (650 megabytes) by using the number of Christian Bibles that can be stored. The King James Version of the Bible in uncompressed plain 8-bit text contains about 4.5 million characters, so a CD-ROM can store about 150 Bibles. The print version of the Encyclopædia Britannica is another common data volume metric. It contains approximately 300 million characters, so two copies would fit onto a CD-ROM and still have 50 megabytes (or about 11 bibles) left over. The term Library of Congress is often used. It refers to the US Library of Congress. Information researchers have estimated that the entire print collections of the Library of Congress represent roughly 10 terabytes of uncompressed textual data.
== External links == International HapMap Project Archived 2014-04-16 at the Wayback Machine Delaware Valley Personalized Medicine Project Uses SNPs to help make medicine personal Genotyping by Oligonucleotide Ligation Assay (OLA) Why SNP test your mice?
Sources: en.wikipedia.org
γ-Amino-β-hydroxybutyric acid (GABOB), also known as β-hydroxy-γ-aminobutyric acid (β-hydroxy-GABA), sold under the brand name Gamibetal among others, is an anticonvulsant which is used for the treatment of epilepsy in Europe, Japan, and Mexico. It is a GABA analogue, or an analogue of the neurotransmitter γ-aminobutyric acid (GABA), and has been found to be an endogenous metabolite of GABA.
It looked terrible coming at the fag end of the recession, when the government had a tiny majority, and just after the fiasco of Black Wednesday and the scandal of David Mellor's resignation. Heseltine was attacked by Marcus Fox, Jim Pawsey, Nicholas Winterton, Bill Cash, Rhodes Boyson and his former supporter David Evans who called openly for him to be sacked. The High Court found that Heseltine and British Coal had acted "unlawfully and irrationally". Faced with likely defeat in the House of Commons, Heseltine was forced to agree to a moratorium, during which time he attempted, largely unsuccessfully, to seek new markets for British coal and to obtain government subsidies for pits. The band Chumbawamba released the critical song "Mr Heseltine meets the public" that portrayed Heseltine as an out-of-touch figure; the same group had once dedicated a song to the village of Fitzwilliam, West Yorkshire, which was reduced to a ghost village by the closure of the local coal pits. In February 1993, Heseltine announced that unlike the Dutch and Belgian governments, Britain would not be contributing to any bailout of Anglo-Dutch DAF Trucks (which in the event went bankrupt in June). By early 1993 Heseltine's fortunes were at a low ebb, with his future as a minister being called into question. A review into the pit closures appeared in March 1993. By this time, public anger had cooled. By the start of 1997, British Coal had been reduced to 28 pits.
=== Br === Roscoe Brady (1923–2016). American biochemist at the National Institute of Neurological Disorders and Stroke, who identified many enzyme defects responsible for metabolic diseases. Member Natl. Acad. Sci. USA. Herman Branson (1914–1995). American physicist and biochemist who participated at Caltech in the discovery of the α-helix Sydney Brenner (1927–2019). South African biochemist at Cambridge, and later Berkeley, known for work on the genetic code and more recently for establishing Caenorhabditis elegans as a model organism. Nobel prize in Physiology or Medicine (2002) Roger Brent (b. 1955). American molecular biologist at the University of Washington known for work on gene regulation and systems biology Kenneth Breslauer (b. 1947). American biochemist at Rutgers University (born in Sweden of German parents), who has studied DNA damage and repair, including why certain mutations escape repair and result in cancer. Bernard Brodie (1907–1989). American biochemist and pharmacologist at the National Heart Institute, regarded as the founder of modern pharmacology. He studied drug metabolism and the mechanisms of drug effects. Member Natl. Acad. Sci. USA. Adrian John Brown FRS (1852–1920). British expert on brewing and malting at the University of Birmingham. He was a pioneer of enzyme kinetics and proposed an explanation of enzyme saturation. Patrick O. Brown (b. 1954). American biochemist at Stanford.
=== Flight-time equivalent dose === Natural background radiation typically increases with altitude above the earth's surface. Utilizing this phenomenon, dose resulting from radiological exposures can be expressed in units of flight-time. Flight-time equivalent dose is defined as the time spent in an aircraft at cruising altitude required to receive a radiological dose approximately equivalent to a radiological exposure such as a medical x-ray. One hour of flight-time is approximately equivalent to a dose of 0.004 millisieverts.
Sources: en.wikipedia.org
Glutathione oxidizes quickly when cells are disrupted or when samples sit at room temperature. Rapid processing or immediate freezing minimizes the conversion of GSH to GSSG. This step helps ensure that the measured ratio reflects the original biological state.
The Tietze assay is an enzymatic recycling method that measures total glutathione. It uses glutathione reductase to reduce GSSG back to GSH, which then reacts with a chromogen or fluorophore. The reaction cycles repeatedly, amplifying the signal for detection.
Yes, but the choice of blood fraction matters. Plasma or serum contains low glutathione levels and is easily affected by hemolysis. Whole blood mainly reflects the high glutathione content of erythrocytes, so results from different fractions are not directly comparable.
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.