A practical reference on thiol: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2026-02-24. Anything still debated is marked as such rather than presented as settled.
Glutathione functions in redox balance, detoxification, and sulfur amino acid storage. It participates in reactions that help maintain ascorbate and protein thiol status. The molecule serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. These enzymes reduce peroxides and conjugate electrophiles, respectively. Glutathione also contributes to the metabolism of xenobiotics and to the transport of cysteine between tissues. How interorgan transport and tissue-specific regulation shape whole-body pools remains an active area of study.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its cysteine residue carries a thiol group, which allows the molecule to participate in reduction and oxidation reactions. The compound exists in most living cells, where the reduced form, often abbreviated GSH, is usually more abundant than the oxidized disulfide form, GSSG. Intracellular concentrations are commonly in the millimolar range, while extracellular concentrations are much lower. This uneven distribution supports its role as a major cellular redox buffer.
Cells synthesize glutathione through two ATP-dependent enzymatic steps. The first step combines glutamate and cysteine to form gamma-glutamylcysteine, catalyzed by glutamate-cysteine ligase. The second step adds glycine, producing the complete tripeptide, catalyzed by glutathione synthetase. Glutathione itself can inhibit the first enzyme, providing negative feedback when levels are high. Because cysteine is often limiting, its availability influences how quickly the pathway proceeds. These reactions occur in the cytosol, and the resulting glutathione can be distributed to other compartments.
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 |
|---|---|---|
| Chemical formula | C10H17N3O6S | Reduced glutathione (GSH) |
| Molar mass | 307.32 g/mol | Calculated for C10H17N3O6S |
| Appearance | White to off-white powder | Typical solid form |
| Solubility | Water-soluble | Polar tripeptide |
| Common synonyms | GSH; L-glutathione | Gamma-glutamylcysteinylglycine |
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.
Glutathione is a small tripeptide made of glutamic acid, cysteine, and glycine. Its cysteine thiol group allows reversible oxidation and reduction, making it central to cellular redox chemistry. The reduced form, often abbreviated GSH, predominates inside most cells, while the oxidized disulfide form, GSSG, forms when two GSH molecules react. The ratio of GSH to GSSG is widely used as an indicator of oxidative stress in laboratory research, though it does not by itself diagnose a clinical condition.
Glutathione is a small tripeptide built from glutamic acid, cysteine, and glycine. Its peptide bond between glutamate and cysteine involves the gamma-carboxyl group rather than the usual alpha-carboxyl group. This structure gives the molecule a reactive thiol on the cysteine residue. The reduced form, often abbreviated GSH, is the predominant intracellular species in many cell types. Because the thiol can donate electrons, glutathione participates in redox chemistry and in the conjugation of reactive molecules.
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.
Bohemian-style absinth is also referred to as Czech-style absinthe, anise-free absinthe, or just "absinth" (without the "e"), and is best described as a wormwood bitters. It is produced mainly in the Czech Republic, from which it gets its designation as Bohemian or Czech, although not all absinthes from the Czech Republic are Bohemian-style. Bohemian-style absinth typically contains little or none of the anise, fennel, and other herbal flavours associated with traditional absinthe, and thus bears very little resemblance to the absinthes made popular in the 19th century. Typical Bohemian-style absinth has only two similarities with its authentic, traditional counterpart: it contains wormwood and has a high alcohol content. The Czechs are credited with inventing the fire ritual in the 1990s, possibly because Bohemian-style absinth does not louche, which renders the traditional French preparation method useless. As such, this type of absinthe and the fire ritual associated with it are entirely modern fabrications and have little to no relationship with the historical absinthe tradition.
Cell Centered Database – Astrocyte UIUC Histology Subject 57 "Astrocytes" Archived 2012-11-21 at the Wayback Machine at Society for Neuroscience The Department of Neuroscience at Wikiversity NIF Search – Astrocyte via the Neuroscience Information Framework
A vial (also known as a phial or flacon) is a small glass or plastic vessel or bottle, often used to store medication in the form of liquids, powders, or capsules. They can also be used as scientific sample vessels; for instance, in autosampler devices in analytical chromatography. Vial-like glass containers date back to classical antiquity; modern vials are often made of plastics such as polypropylene. There are different types of vials such as a single dose vial and multi-dose vials often used for medications. The single dose vial is only used once whereas a multi-dose vial can be used more than once. The CDC sets specific guidelines on multi-dose vials.
=== Inhibin === In contrast to activin, much less is known about the mechanism of action of inhibin, but may involve competing with activin for binding to activin receptors and/or binding to inhibin-specific receptors.
As can be seen, trypsinogen activation to trypsin is essential, because it activates its own reaction, as well as the reaction of both chymotrypsin and elastase. Therefore, it is essential that this activation does not occur prematurely. There are several protective measures taken by the organism to prevent self-digestion:
Sources: en.wikipedia.org
Nando's opened its first restaurants within the United Kingdom, in 1992, in the west London suburbs of Ealing and Earls Court, initially focusing on takeaway food. The UK arm, owned by the Enthoven family via a private equity company, struggled until chairman Dick Enthoven put his son Robert in control. The focus then moved from takeaways to a mixed-service (counter ordering and table service) model. This decision was taken after Nando's partnered with Harrison, a branding and design agency. They also advised Nando's to design each restaurant individually so no two restaurants were the same, a brand characteristic of the chain. In 2013, the company employed around 8,000 staff in the UK and had over 280 branches, with about 60 serving food conforming with Islamic dietary laws. In 2010, Nando's UK won the Sunday Times's 'best place to work' award in the big company category. Its sauces and marinades were also retailed in UK supermarkets. Nando's claims to have the largest collection of South African art in the UK, with over 5,000 works displayed in restaurants; original artworks are commissioned by the company. In March 2020, all of Nando's UK restaurants closed temporarily due to nationwide lockdown rules introduced by the government to limit the spread of COVID-19. In late April 2020, Nando's reopened select locations for delivery and collection services, with many more locations opening throughout May. In early July 2020, the restaurant chain started reopening a few of its outlets for eat-in service.
=== Scandinavian === Scandinavian American Fraternity - Founded in 1893. Membership was open to Christians of Scandinavian descent who were of good moral character. The by-laws prohibited discussing religious or political subjects. There was a ritualistic element to the fraternity, including a lodge altar and a burial service, that was criticized by Christian Cynosure as being "heathen", though prominent churchmen such as the Rev. P. R. Syrdal of the Norwegian Lutheran Church of America were active members who defended the organization. Grand Lodge headquarters at Eau Claire, Wisconsin. In 1923 it had 8,085 benefit members and 71 social members spread across Wisconsin, Minnesota, Illinois, and North Dakota. Scandinavian Fraternity of America - Founded in 1915 as the consolidation of three other groups including the Scandinavian Brotherhood of America, which had been founded in 1894. Membership began to decline in the 1980s, dropping from 37 lodges in 1983 to 28 in 1985. In 1991 it was reported to have only 2,500 members, a number repeated in 1995.
== Scope == Medical genetics encompasses many different areas, including clinical practice of physicians, genetic counselors, and nutritionists, clinical diagnostic laboratory activities, and research into the causes and inheritance of genetic disorders. Examples of conditions that fall within the scope of medical genetics include birth defects and dysmorphology, intellectual disabilities, autism, mitochondrial disorders, skeletal dysplasia, connective tissue disorders, cancer genetics, and prenatal diagnosis. Medical genetics is increasingly becoming relevant to many common diseases. Overlaps with other medical specialties are beginning to emerge, as recent advances in genetics are revealing etiologies for morphologic, endocrine, cardiovascular, pulmonary, ophthalmologist, renal, psychiatric, and dermatologic conditions. The medical genetics community is increasingly involved with individuals who have undertaken elective genetic and genomic testing.
DNA-encoded chemical libraries (DECL) is a technology for the synthesis and screening on an unprecedented scale of collections of small molecule compounds. DECL is used in medicinal chemistry to bridge the fields of combinatorial chemistry and molecular biology. The aim of DECL technology is to accelerate the drug discovery process and in particular early phase discovery activities such as target validation and hit identification. DECL technology involves the conjugation of chemical compounds or building blocks to short DNA fragments that serve as identification bar codes and in some cases also direct and control the chemical synthesis. The technique enables the mass creation and interrogation of libraries via affinity selection, typically on an immobilized protein target. A homogeneous method for screening DNA-encoded libraries (DELs), known as Binder Trap Enrichment (BTE), was described in 2015 and uses water-in-oil emulsion technology to isolate, count and identify individual ligand-target complexes in a single-tube approach. In contrast to conventional screening procedures such as high-throughput screening, biochemical assays are not required for binder identification, in principle allowing the isolation of binders to a wide range of proteins historically difficult to tackle with conventional screening technologies.
Sources: en.wikipedia.org
NASA's aim for food on the ISS is to make the experience as close as possible to that of Earth, and they aim to provide more acceptable and palatable foods. Modern astronauts have a greater variety of main courses to choose from and many astronauts request personalized menus from lists of available foods including items like fruit salad and spaghetti. Fresh fruits and vegetables that can be safely stored at room temperature are eaten on space flights. Astronauts sometimes request beef jerky for flights, as it has an extended shelf life and a strong flavor. Food on the ISS is similar to the Shuttle, in that it is individually packaged to allow for exchanges and prevent issues in the microgravity environment. Due to the limited water supply, an emphasis has been placed on thermostabilized foods rather than rehydration methods. Since 2002, the small LADA Greenhouse system (the leaf chamber is just 16 x 20 x 26 cm/6 x 8 x 10 inches) has been used on board the International Space Station to study how plants grow in microgravity and to grow edible vegetables for the astronauts. LADA includes a control module and was sent to the station already equipped with the root media for the plants to be grown and eaten in space.
== Applications == Pumps that use oil either as their working fluid (diffusion pumps), or as their lubricant (mechanical rotary pumps), are often the sources of contamination in vacuum systems. Placing a cold trap at the mouth of such a pump greatly lowers the risk that oil vapours will backstream into the cavity. Cold traps can also be used for experiments involving vacuum lines such as small-scale very low temperature distillations/condensations. This is accomplished through the use of a coolant such as liquid nitrogen or a freezing mixture of dry ice in acetone or a similar solvent with a low melting point. Liquid nitrogen is only used when dry ice or other cryogenic approaches will not condense the desired gasses since liquid nitrogen will also condense oxygen. Any oxygen gas content in the vacuum line or any leak in the vacuum line will result in liquid oxygen mixed with the target vapors, often with explosive results. When performed on a larger scale, this technique is called freeze-drying, and the cold trap is referred to as the condenser. Cold traps are also used in cryopump systems to generate hard vacua by condensing the major constituents of the atmosphere (nitrogen, oxygen, carbon dioxide and water) into their liquid or solid forms. An igloo or other snow bivouac may exploit the same principle – confinement of denser cool air within an impermeable lower volume – to reduce cold air reaching the occupants through use of a sump or cill around a raised sleeping platform within.
=== EC 2.2.1: Transketolases and Transaldolases === EC 2.2.1.1: transketolase EC 2.2.1.2: transaldolase EC 2.2.1.3: formaldehyde transketolase EC 2.2.1.4: acetoin—ribose-5-phosphate transaldolase EC 2.2.1.5: 2-hydroxy-3-oxoadipate synthase EC 2.2.1.6: acetolactate synthase EC 2.2.1.7: 1-deoxy-D-xylulose-5-phosphate synthase EC 2.2.1.8: fluorothreonine transaldolase EC 2.2.1.9: 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylic-acid synthase EC 2.2.1.10: 2-amino-3,7-dideoxy-D-threo-hept-6-ulosonate synthase EC 2.2.1.11: 6-deoxy-5-ketofructose 1-phosphate synthase EC 2.2.1.12: 3-acetyloctanal synthase EC 2.2.1.13: apulose-4-phosphate transketolase EC 2.2.1.14: 6-deoxy-6-sulfo-D-fructose transaldolase
Sources: en.wikipedia.org
Glutathione is built from three amino acids: glutamate, cysteine, and glycine. The linkage involves the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group, which is unusual for peptides. This structure protects the bond from some common peptidases.
It is present in nearly all cells, with notable amounts in the liver, kidneys, and red blood cells. The highest intracellular concentrations are usually in the millimolar range. Levels differ by tissue, age, and physiological state.
It is not classified as an essential nutrient because cells can synthesize it from amino acids. Dietary sources exist, but their contribution to tissue pools is not fully established. The body's production depends on enzyme activity and precursor availability.
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.