redox buffering raises a handful of sensible questions. This page answers them in order, starting with the fundamentals and moving to applications.
Reviewed 2026-07-27. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced form; oxidized dimer is C20H32N6O12S2 |
| Molar mass | 307.32 g/mol | For reduced glutathione (GSH) |
| Appearance | White crystalline powder | Typical laboratory and supplement-grade material |
| Solubility | Soluble in water | Poorly soluble in ethanol and other nonpolar solvents |
| Typical storage | -20 C, desiccated, protected from light | Reduced form can oxidize in solution |
In its reduced form, glutathione carries a sulfhydryl group that can donate electrons. This property lets it act as a major cellular antioxidant and redox buffer. Glutathione peroxidase uses it to reduce hydrogen peroxide and lipid peroxides, while glutathione reductase regenerates the reduced form using NADPH. The ratio of reduced glutathione to glutathione disulfide is widely used as an indicator of oxidative stress, though the ratio changes with compartment, cell type, and sample handling. Oxidized glutathione can also form mixed disulfides with proteins, affecting their activity.
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.
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.
=== Infection control concerns === Studies have shown that doctor's coats worn in hospitals can harbor contagions including MRSA. In 2007, the UK National Health Service (NHS) started banning long-sleeved coats. In 2009, the American Medical Association investigated banning coats with long sleeves to protect patients, but did not institute a ban. A study published in 2011 investigating the effectiveness of the NHS ban showed no statistical difference in contamination levels over an 8-hour period between residents wearing long-sleeved coats and those wearing short-sleeved scrubs. In an effort to reduce the contamination of healthcare uniforms, ASTM International is developing standards to specifically address liquid penetration resistance, liquid repellency, bacterial decontamination, and antimicrobial properties of such uniforms. The spread of white coat infection has been rampant and talked about in the scientific community. Indian physician Edmond Fernandes triggered a controversy in India and parts of South Asia by calling for a ban on white coats because of the spread of nosocomial infections.
Diphenoxylate (Lomotil, R-1132) is a centrally active opioid drug of the phenylpiperidine series that is used as a combination drug, prescribed in the United States under the trade name Lomotil, with atropine for the treatment of diarrhea. Diphenoxylate is an opioid and acts by slowing intestinal contractions; the atropine is present to prevent drug abuse and overdose. It should not be given to children due to the risk that they will stop breathing and should not be used in people with Clostridioides difficile infection.
The technology of this combined stimulation bioreactor could be used to grow bone cells more quickly and effectively in future clinical stem cell therapies. MC2 Biotek has also developed a bioreactor known as ProtoTissue that uses gas exchange to maintain high oxygen levels within the cell chamber; improving upon previous bioreactors, since the higher oxygen levels help the cell grow and undergo normal cell respiration. Active areas of research on bioreactors includes increasing production scale and refining the physiological environment, both of which could improve the efficiency and efficacy of bioreactors in research or clinical use. Bioreactors are currently used to study, among other things, cell and tissue level therapies, cell and tissue response to specific physiological environment changes, and development of disease and injury.
== Fictional history == In this fictional universe, the Culture exists concurrently with human society on Earth. The time frame for the published Culture stories is from 1267 CE to roughly 2970 CE, with Earth being contacted around 2100 CE, though the Culture had covertly visited the planet in the 1970s in The State of the Art. The Culture itself is described as having been created when several humanoid species and machine sentiences reached a certain social level, and took not only their physical, but also their civilisational evolution into their own hands. In The Player of Games, the Culture is described as having existed as a space-faring society for eleven thousand years. In The Hydrogen Sonata, one of these founding civilisations was named as the Buhdren Federality.
Although these are both aspects of earthworm activities the net effect is important to ascertain, in particular in the frame of organic matter disappearance linked to global warming. It seems that there is now a consensus about the prominent role of earthworms in carbon sequestration due to the fact that part of organic matter is mineralized at or near the soil surface while the major part is incorporated in the deep soil where it is stabilized by links with clay minerals.
Sources: en.wikipedia.org
Solar distillation relies on sunlight to warm and evaporate the water to be purified which then condenses and trickles into a container. In theory, a solar (condensation) still removes all pathogens, salts, metals, and most chemicals but in field practice the lack of clean components, easy contact with dirt, improvised construction, and disturbances result in cleaner, yet contaminated water.
=== Sarcopenia and sarcopenic obesity === In a recently published scoping review led by Kalra, the current evidence linking sarcopenic obesity with cardiovascular disease has been summarised, along with proposed preventive and therapeutic strategies. He has published extensively to enable the diagnosis of sarcopenia and sarcopenic obesity in resource-constrained settings and has led the development of a South Asian consensus document on the subject.
1833: English phycologists Amelia Griffiths and Mary Wyatt published two books on local British seaweeds. Griffiths had an internationally respected reputation as a skilled seaweed collector and scholar, and Swedish botanist Carl Agardh had earlier named the seaweed genus Griffithsia in her honour. 1833: American botanical and scientific illustrator Orra White Hitchcock was best known for illustrating the scientific works of her husband, geologist Edward Hitchcock (1793–1864), but was also notable for her own artistic and scientific work. The most well known appear in her husband's seminal works, the 1833 Report on the Geology, Mineralogy, Botany, and Zoology of Massachusetts and its successor, the 1841 Final Report produced when he was State Geologist. For the 1833 edition, Pendleton's Lithography (Boston) lithographed nine of Hitchcock's Connecticut River Valley drawings and printed them as plates for the work. In 1841, B. W. Thayer and Co., Lithographers (Boston) printed revised lithographs and an additional plate. The hand-colored plate "Autumnal Scenery. View in Amherst" is Hitchcock's most frequently seen work. 1835: Scottish polymath Mary Somerville and German astronomer Caroline Herschel were elected the first female members of the Royal Astronomical Society. 1836: Early English geologist and paleontologist Etheldred Benett, known for her extensive collection of several thousand fossils, was appointed a member of the Imperial Natural History Society of Moscow.
==== Bacterial ==== Studies have shown that bacterial infections of the human urinary tract, vagina (i.e., bacterial vaginosis), gums (i.e., periodontitis), and abscesses in various tissues are associated with high concentrations of SCFAs, especially acetic acid, at the infection sites or, in urinary tract infections, the urine. These SCFAs may be made and released by the bacteria and/or host cells in the infected areas. Several studies have suggested that SCFAs act through FFAR2 to suppress these infections. 1) Compared to control mice, Ffar2 gene knockout mice had more severe infections in models of Citrobacter rodentium, Klebsiella pneumoniae, Clostridioides difficile, and Streptococcus pneumoniae bacterial infections. 2) Injection of acetic acid into the peritoneum 1/2 hour before or 6 hours after injection of Staphylococcus aureus bacteria into the bloodstream of mice reduced signs of severe disease, the amount of body weight lost, and the numbers of bacteria recovered from the liver, spleen, and kidneys; these reductions did not occur in Fffar2 gene knockdown mice. And, 3) higher circulating blood cell levels of FFAR2 messenger RNA were associated with higher survival rates in patients with sepsis, i.e., disseminated bacterial infections, compared to patients with lower levels of blood cell FFAR2 messenger RNA. These studies suggest that FFAR2 reduces the severity of the cited bacterial infections in humans and mice and recommend further studies on the roles of FFAR2 in these and other bacterial infections.
Sources: en.wikipedia.org
To resolve this dilemma, several mycologists proposed in a 2005 publication to conserve the name Psilocybe, with P. semilanceata as the type. As they explained, conserving the name Psilocybe in this way would prevent nomenclatural changes to a well-known group of fungi, many species of which are "linked to archaeology, anthropology, religion, alternate life styles, forensic science, law enforcement, laws and regulation". Further, the name P. semilanceata had historically been accepted as the lectotype by many authors in the period 1938–68. The proposal to conserve the name Psilocybe, with P. semilanceata as the type was accepted unanimously by the Nomenclature Committee for Fungi in 2009. The mushroom takes its common name from the Phrygian cap, also known as the "liberty cap", which it resembles; P. semilanceata shares its common name with P. pelliculosa, a species from which it is more or less indistinguishable in appearance. The Latin word for Phrygian cap is pileus, nowadays the technical name for what is commonly known as the "cap" of a fungal fruit body. In the 18th century, Phrygian caps were placed on Liberty poles, which resemble the stipe of the mushroom. The generic name is derived from Ancient Greek psilos (ψιλός) 'smooth, bare' and Byzantine Greek kubê (κύβη) 'head'. The specific epithet comes from Latin semi 'half, somewhat' and lanceata, from lanceolatus 'spear-shaped'.
Acutolysin A (also called AaH I) is a toxin found in the snake Agkistrodon acutus venom. It is a member of the adamalysin subfamily of the metzincin family and is a snake venom zinc metalloproteinase possessing only one catalytic domain. AaH I grows crystals under pH 5.0 and 7.5 conditions. AaH I has a single polypeptide chain and a molecular weight of 22 kDa.
=== Illustrative example === The following describes the operation of a simple mass spectrometer that uses sector type. Other types are treated below. Consider a sample of sodium chloride (table salt). In the ion source, the sample is vaporized (turned into gas) and ionized (transformed into electrically charged particles) into sodium (Na+) and chloride (Cl−) ions. Sodium atoms and ions are monoisotopic, with a mass of about 23 daltons (symbol: Da or older symbol: u). Chloride atoms and ions come in two stable isotopes with masses of approximately 35 u (at a natural abundance of about 75 percent) and approximately 37 u (at a natural abundance of about 25 percent). The analyzer part of the spectrometer contains electric and magnetic fields, which exert forces on ions traveling through these fields. The speed of a charged particle may be increased or decreased while passing through the electric field, and its direction may be altered by the magnetic field. The magnitude of the deflection of the moving ion's trajectory depends on its mass-to-charge ratio. Lighter ions are deflected by the magnetic force to a greater degree than heavier ions (based on Newton's second law of motion, F = ma). The streams of magnetically sorted ions pass from the analyzer to the detector, which records the relative abundance of each ion type. This information is used to determine the chemical element composition of the original sample (i.e. that both sodium and chlorine are present in the sample) and the isotopic composition of its constituents (the ratio of 35Cl to 37Cl).
Sources: en.wikipedia.org
It is a tripeptide of glutamic acid, cysteine, and glycine. The linkage between glutamate and cysteine uses the gamma-carboxyl group, which is unusual for peptides.
GSH is the reduced form with a free thiol group. GSSG is the oxidized dimer formed when two GSH molecules join by a disulfide bond.
It is synthesized inside cells and is not classified as an essential dietary nutrient for most people. Dietary and supplemental sources are studied, but direct requirements are not established in the same way as for vitamins.
GSH is the reduced form of glutathione, with a free thiol group on cysteine. GSSG is the oxidized disulfide form, created when two GSH molecules become linked. The two forms exist together, and their balance is often reported as the GSH/GSSG ratio in laboratory studies.