A practical reference on GSH: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-08-01. Anything still debated is marked as such rather than presented as settled.
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.
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.
For solid glutathione reagents, storage at low temperature and protection from moisture and light are typical precautions. Aqueous solutions can oxidize over time, and pH affects stability; alkaline conditions generally promote thiol oxidation. Some protocols prepare fresh solutions, while others use antioxidants or chelators to limit metal-catalyzed oxidation. Purity and counterion content can vary among commercial preparations, affecting concentration calculations. Certificates of analysis and validated assays help verify identity and purity.
Measuring glutathione in biological samples requires attention to oxidation, because GSH can convert to GSSG after sample collection. Blood and plasma samples are often treated with acid or alkylating agents to preserve the reduced form. Without stabilization, apparent GSH concentrations can fall while GSSG rises. Differences in sample type, handling delay, and deproteinization method can produce results that are not comparable across studies. Reporting preanalytical details is therefore important for interpreting findings.
Common analytical approaches include enzymatic recycling assays, high-performance liquid chromatography, and mass spectrometry. Enzymatic recycling measures total glutathione after converting GSSG back to GSH, while separation methods can quantify GSH and GSSG separately. Derivatization may be used to improve detection or stability during analysis. LC-MS/MS offers high specificity and can distinguish glutathione from related thiols and adducts. Each method has different sensitivity, throughput, and susceptibility to interference, so method selection depends on the study question and sample matrix.
| 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 |
Cells synthesize glutathione through two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine, and glutathione synthetase adds glycine to form the complete tripeptide. Breakdown occurs through gamma-glutamyl transpeptidase and subsequent peptidase reactions, forming the gamma-glutamyl cycle. Within cells, glutathione also forms a disulfide-linked dimer called GSSG when two GSH molecules react. The balance between GSH and GSSG is widely used as an indicator of oxidative conditions, although the ratio can vary by compartment and tissue.
Glutathione supports several cellular processes beyond direct antioxidant action. It serves as a cofactor for glutathione peroxidase and glutathione S-transferase enzymes, which reduce peroxides and conjugate electrophiles, respectively. The molecule also acts as a reservoir of cysteine, an amino acid that can limit protein synthesis and redox signaling. In human nutrition, oral glutathione is sold as a supplement, but how much intact glutathione reaches tissues after ingestion remains an active research question. Clinical claims about supplementation are not uniformly supported by controlled trials.
Storage conditions strongly influence glutathione stability. The solid reduced form is commonly kept desiccated at or below minus twenty degrees Celsius, protected from light and moisture. Aqueous solutions are less stable because the thiol group reacts with dissolved oxygen, and oxidation accelerates at neutral or alkaline pH. Acidic solutions and oxygen-free handling can slow degradation, but repeated freeze-thaw cycles should be avoided. Researchers often verify concentration before use, because apparent losses can arise from oxidation or water uptake.
Measuring glutathione in biological samples requires attention to oxidation and matrix effects. High-performance liquid chromatography with ultraviolet or fluorescence detection can separate reduced and oxidized forms after derivatization. Liquid chromatography with tandem mass spectrometry offers higher specificity and can quantify glutathione alongside related thiols. Because glutathione can oxidize during sample handling, many protocols use rapid acidification with metaphosphoric acid or sulfosalicylic acid. Internal standards help correct for losses during extraction and analysis.
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.
=== Speech and sound creation === Sound synthesis, various methods of sound generation in audio electronics Wave field synthesis, a spatial audio rendering technique, characterized by creation of virtual acoustic environments Subtractive synthesis, a method of creating a sound by removing harmonics, characterised by the application of an audio filter to an audio signal Frequency modulation synthesis, a form of audio synthesis where the timbre of a simple waveform is changed by frequency modulating it with a modulating frequency that is also in the audio range Speech synthesis, the artificial production of human speech
=== Cell and scaffold-based cartilage regeneration === In order to restore joint cartilage after injury due to chondrocyte loss, cell therapy and chondrocyte replenishment has been shown to work in certain studies. Lying self-assembled MSCs (mesenchymal stem cells) on top of chondrocyte-laden hydrogel scaffolds has shown cell-mediated regeneration of hyaline-like cartilage. However, one drawback of this is that implantation of these scaffolds requires open-joint surgery to gather donor chondrocytes from non-weight-bearing joint cartilage areas. This makes it difficult to apply to the elderly. Along with regenerative therapies there are also several studies that show ways to develop new artificial cartilage.
== See also == Hebrews Twelve Tribes of Israel Genetic history of the Middle East Genetic studies of Jews Genetic studies of Samaritans Demographic history of Palestine (region) History of the Jews and Judaism in the Land of Israel Groups claiming affiliation with the Israelites
=== Phase II === Study 980231 (Randomized, double-blind, placebo-controlled). Three dose regimens were included: "pre-post", "pre", and placebo Palifermin administration (60 micrograms/kg) by IV for three consecutive days before chemotherapy and after autologous peripheral blood progenitor cell (PBPC). Efficacy was demonstrated in the drug versus the placebo.
== Non-functional proton coupled amino acid transporter == In hereditary disease iminoglycinuria, there is a defect in the human proton-coupled amino acid transporter 1 and 2 genes which results in a defect in the absorption of proline and glycine. Iminoglycinuria is an autosomal recessive disorder of the renal tubular. Lack of glycine and proline absorption leads to excess urinary excretions containing amino acids. If the transporters are not working properly, a drug that they usually help gain entry in to the cell might not be absorbed Their function can also be inhibited by tryptophan derivatives and allow for exploration into the function of hPAT1 and hPAT2. Additionally, mutations that lead to structural changes in amino acid binding sites play a role in their functional transport.
Sources: en.wikipedia.org
Due to its location on the coast of the Channel, the climate of Le Havre is temperate oceanic. Days without wind are rare. There are maritime influences throughout the year. According to the records of the meteorological station of the Cap de la Heve (from 1961 to 1990), the temperature drops below 0 °C (32 °F) on 24.9 days per year and it rises above 25 °C (77 °F) on 11.3 days per year. The average annual sunshine duration is 1,785.8 hours per year. Precipitation is distributed throughout the year, with a maximum in autumn and winter. The months of June and July are marked by some thunderstorms on average 2 days per month. One of the characteristics of the region is the high variability of the temperature, even during the day. The prevailing winds are from the southwest sector for strong winds and north-north-east for breezes, snowstorms occur in winter, especially in January and February.
The two substrates of this enzyme are (S)-dihydroorotic acid and oxidised nicotinamide adenine dinucleotide phosphate (NADP+). Its products are orotic acid, reduced NADPH, and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (S)-dihydroorotate:NADP+ oxidoreductase. Other names in common use include orotate reductase, dihydroorotate dehydrogenase, dihydro-orotic dehydrogenase, L-5,6-dihydro-orotate:NAD+ oxidoreductase, and orotate reductase (NADPH). It has one cofactor, FAD.
=== New approaches to target biofilms === The application of nanoparticles (NP) are one of novel promising techniques to target biofilms due to their high surface-area-to-volume ratio, their ability to penetrate to the deeper layers of biofilms and the capacity to releasing antimicrobial agents in a controlled way. Studying NP-EPS interactions could provide deeper understanding on how to develop more effective nanoparticles. "smart release" nanocarriers that can penetrate biofilms and be triggered by pathogenic microenvironments to deliver drugs or multifunctional compounds, such as catalytic nanoparticles to aptamers, dendrimers, and bioactive peptides) have been developed to disrupt the EPS and the viability or metabolic activity of the embedded bacteria. Some factors that would alter the potentials of the NP to transport antimicrobial agents into the biofilm include physicochemical interactions of the NP with EPS components, the characteristics of the water spaces (pores) within the EPS matrix and the EPS matrix viscosity. Size and surface properties (charge and functional groups) of the NPs are the major determinants of the penetration in and the interaction with the EPS. Another potential antibiofilm strategy is phage therapy. Bacteriophages, viruses that invade specific bacterial host cells, were suggested to be effective agents in penetrating biofilms.
By the mid-1900s, lichenologists were already exploiting chemical traits for classification—decades before such methods reached vascular plant taxonomy. Because many lichens synthesize distinctive secondary metabolites (specialized compounds including lichen products unique to these organisms), workers devised simple spot tests in which reagents applied to the thallus yield diagnostic colour changes. The technique dates to the 1860s, but by 1951, the tests were routine. Elke Mackenzie listed K (potassium hydroxide solution), C (sodium hypochlorite), and Pd (p-phenylenediamine) as key diagnostic reagents because species often differ in their colour reactions. For example, a yellow K reaction usually signals the presence of the common metabolite atranorin, whereas a deep-red Pd reaction suggests certain depsidones. The chemical toolbox expanded sharply with the adoption of thin-layer chromatography (TLC) in the late 1960s. Chicita F. Culberson's Chemical and Botanical Guide to Lichen Products (1969) laid out a reproducible protocol for separating trace compounds from minute thallus chips, making TLC profiles a standard component of species descriptions. David Hawksworth's 1976 synthesis went a step further by integrating metabolite patterns into family‑ and order‑level frameworks, demonstrating that chemistry could diagnose natural groups and foreshadowing the molecular phylogenies that would follow. Chemical tests revealed cryptic diversity beneath outwardly uniform lichens.
Sources: en.wikipedia.org
== References == This article was submitted to WikiJournal of Science for external academic peer review in 2017 (reviewer reports). The updated content was reintegrated into the Wikipedia page under a CC-BY-SA-3.0 license (2018). The version of record as reviewed is: Mike Christie; et al. (2018). "Radiocarbon dating" (PDF). WikiJournal of Science. 1 (1): 6. doi:10.15347/wjs/2018.006. Wikidata Q55120317.
A meta-analysis conducted in 2007 and updated in 2020 by the international Cochrane Collaboration, which reviewed numerous randomized controlled trials, found that treatment with glargine and detemir insulins resulted in fewer cases of hypoglycemia compared to NPH insulin. Additionally, treatment with detemir was associated with a reduction in the frequency of severe hypoglycemia. However, the review acknowledged limitations, such as the use of low glucose and Hemoglobin A1c targets, which could affect the generalizability of these findings to routine clinical practice. In 2007, a report from Germany's Institute for Quality and Cost Effectiveness in the Health Care Sector (IQWiG) concluded that there was insufficient evidence to support the superiority of short-acting insulin analogues over synthetic human insulin for the treatment of adult patients with type 1 diabetes. Many of the studies reviewed were criticized for being too small to provide statistically reliable results, and notably, none were blinded.
==== European Union ==== The European Union's (EU) Food Supplements Directive of 2002 requires that supplements be demonstrated to be safe, both in dosages and in purity. Only those supplements that have been proven to be safe may be sold in the EU without prescription. As a category of food, food supplements cannot be labeled with drug claims but can bear health claims and nutrition claims. The dietary supplements industry in the United Kingdom (UK), one of the 28 countries in the bloc, strongly opposed the Directive. In addition, a large number of consumers throughout Europe, including over one million in the UK, and various doctors and scientists, had signed petitions by 2005 against what are viewed by the petitioners as unjustified restrictions of consumer choice. In 2004, along with two British trade associations, the Alliance for Natural Health (ANH) had a legal challenge to the Food Supplements Directive referred to the European Court of Justice by the High Court in London. Although the European Court of Justice's Advocate General subsequently said that the bloc's plan to tighten rules on the sale of vitamins and food supplements should be scrapped, he was eventually overruled by the European Court, which decided that the measures in question were necessary and appropriate for the purpose of protecting public health. ANH, however, interpreted the ban as applying only to synthetically produced supplements, and not to vitamins and minerals normally found in or consumed as part of the diet.
== Overview == When an elastic material is deformed due to an external force, it experiences internal resistance to the deformation so that it is restored to its original state if the external force is no longer applied. There are various elastic moduli, such as Young's modulus, the shear modulus, and the bulk modulus, all of which are measures of the inherent elastic properties of a material as a resistance to deformation under an applied load. The various moduli each apply to different kinds of deformation. For instance, Young's modulus applies to extension or ←compression of a body, whereas the shear modulus applies to its shear. Young's modulus and shear modulus only apply to solids, whereas the bulk modulus applies to solids, liquids, and gases. The elasticity of materials is described by a stress–strain curve, which shows the relation between stress (the average restorative internal force per unit area) and strain (the relative deformation). The curve is generally nonlinear, but it can (by use of a Taylor series) be approximated as linear for sufficiently small deformations (in which higher-order terms are negligible). If the material is isotropic, the linearized stress–strain relationship is called Hooke's law, which is often presumed to apply up to the elastic limit for most metals or crystalline materials whereas nonlinear elasticity is generally required to model large deformations of rubbery materials even in the elastic range.
The club is recorded as having played at McCracken's Paddock, Glass's Paddock, and Flemington Hill. It is likely that these are three different names for the one ground, given that McCracken's Paddock was a parcel of land that sat within the larger Glass's Paddock, which in turn was situated in an area widely known at the time as Flemington Hill. In 1882, the club moved home games to the East Melbourne Cricket Ground (since demolished) after an application to play on the Essendon Cricket Ground (later known as Windy Hill) was voted down by Lord Mayor of the City of Essendon, James Taylor, on the basis that the considered the Essendon Cricket Ground "to be suitable only for the gentleman's game of cricket". The club became known by the nickname "the Same Old Essendon" from the title and hook of the principal song performed by a band of supporters which regularly occupied a section of the grandstand at the club's games. The nickname first appeared in print in the local North Melbourne Advertiser in 1889, and ended up gaining wide use, often as the diminutive "Same Olds". This move away from Essendon, at a time when fans would walk to their local ground, didn't go down too well with many Essendon people; and, as a consequence, a new team and club was formed in 1900, unconnected with the first (although it played in the same colours), that was based at the Essendon Cricket Ground, and playing in the Victorian Football Association. It was known firstly as Essendon Town and, after 1905, as Essendon (although it was often called Essendon A, with the A standing for association).
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.
Preanalytical factors such as sample type, time to processing, and stabilization method can change GSH and GSSG amounts. Analytical method and calibration also contribute to variation. Comparing absolute values across studies requires caution.