Everything below concerns redox buffering. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-08. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
| 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 |
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.
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.
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.
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 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.
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.
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.
=== Phosphoenolpyruvate carboxykinase === Mitochondrial phosphoenolpyruvate carboxykinase is thought to participate in the transfer of the phosphorylation potential from the matrix to the cytosol and vice versa. However, it is strongly favored towards GTP hydrolysis, thus it is not really considered as an important source of intra-mitochondrial substrate-level phosphorylation.
The two substrates of this enzyme are (R,R)-butane-2,3-diol and NAD+; its products are (R)-acetoin, nicotinamide adenine dinucleotide (NADH), and a proton. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is (R,R)-butane-2,3-diol:NAD+ oxidoreductase. Other names in common use include butyleneglycol dehydrogenase, D-butanediol dehydrogenase, D-(−)-butanediol dehydrogenase, butylene glycol dehydrogenase, diacetyl (acetoin) reductase, D-aminopropanol dehydrogenase, D-aminopropanol dehydrogenase, 1-amino-2-propanol dehydrogenase, 2,3-butanediol dehydrogenase, D-1-amino-2-propanol dehydrogenase, (R)-diacetyl reductase, (R)-2,3-butanediol dehydrogenase, D-1-amino-2-propanol:NAD+ oxidoreductase, 1-amino-2-propanol oxidoreductase, and aminopropanol oxidoreductase. This enzyme participates in butanoic acid metabolism.
== Prognosis == As of 2012, the five-year survival rate for systemic scleroderma was about 85%, whereas the 10-year survival rate was just under 70%. This varies according to the subtype; while localized scleroderma rarely results in death, the systemic form can, and the diffuse systemic form carries a worse prognosis than the limited form. The major scleroderma-related causes of death are: pulmonary hypertension, pulmonary fibrosis, and scleroderma renal crisis. People with scleroderma are also at a heightened risk for developing osteoporosis and for contracting cancer (especially liver, lung, haematologic, and bladder cancers). Scleroderma is also associated with an increased risk of cardiovascular disease. According to a study of an Australian cohort, between 1985 and 2015, the average life expectancy of a person with scleroderma increased from 66 years to 74 years (the average Australian life expectancy increased from 76 to 82 years in the same period).
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The U.S. 101st Airborne Division and ARVN 1st Division launch Operation Apache Snow in the A Shau Valley. The operation results in 977 PAVN killed and five captured while U.S. losses were 113 killed and ARVN losses were 31 killed. Most of the U.S. casualties were in the Battle of Hamburger Hill from May 13–20 where U.S. forces attacked heavily fortified PAVN positions on Hill 937. 630 PAVN, 72 U.S. and 31 ARVN were killed in the fighting for Hill 937.
Sources: en.wikipedia.org
===== Clinical microbiome analyses ===== The use of mNGS to characterize the microbiome has made possible the development of bacterial probiotics to be administrated as pills, for example, as a treatment of Clostridioides difficile-associated diseases.
(C6H5)3P=CHR + R'−CO−Im → (C6H5)3P+−CHR−COR' + Im− (C6H5)3P+−CHR−COR' + (C6H5)3P=CHR → (C6H5)3P=CR−COR' + (C6H5)3P+−CH2R These can undergo the Wittig reaction to form α,β unsaturated ketones or aldehydes. The reagent can even undergo reaction with peroxide to form the peroxycarboxylic acid, which can react further to form diacyl peroxides. The imidazole group is also reduced by LiAlH4 to form aldehydes from the carboxylic acid (rather than amines or alcohols). The reagent can also be reacted with Grignard reagents to form ketones. A C-C acylation reaction can occur with a malonic ester-type compound, in the following scheme useful for syntheses of macrolide antibiotics.
=== Pharmacokinetics === Kavalactones are quickly absorbed in the gut and vary in bioavailability. They primarily act on brain areas like the limbic system, amygdala, and reticular formation, but their exact molecular mechanisms are not yet fully understood. Data on the pharmacokinetics of kavalactones remain limited. In animal studies, particularly in rats, kavain—the primary kavalactone found in traditional kava preparations—was shown to be well absorbed, with an estimated bioavailability of approximately 50%. In humans, kavain undergoes extensive hepatic metabolism, primarily via cytochrome P450 (CYP) enzyme-mediated pathways, followed by further phase II biotransformation processes such as sulfonation, glucuronidation, and glutathione (GSH) conjugation. In rats administered a 100 mg/kg bodyweight dose of kavain, over 90% was eliminated within 72 hours through urine and feces, either as unchanged compound or as metabolites. No evidence of bioaccumulation has been observed in rats, mice, or humans.
== January 12, 1982 (Tuesday) == Canada's Prime Minister Pierre Trudeau announced that he was reorganizing several Canadian federal ministries, and that the existing Ministry of Industry, Trade and Commerce would be broken up into a Ministry for Economic and Regional Development. Kevin McGrady, a terrorist of the Provisional IRA who had become a born-again Christian, walked into the Musgrave Street police station in Belfast and confessed to 27 crimes committed in 1975, including three murders. After being sentenced to life imprisonment in June, McGrady agreed to become a "supergrass" and his testimony led to the conviction of seven IRA members in 1983. The PBS television series American Playhouse telecast its first play, The Shady Hill Kidnapping, written and narrated by John Cheever. The series would run for 13 seasons, ending on September 29, 1996. Born: Tony Lochhead, New Zealand footballer with 47 caps for the New Zealand national team from 2003 to 2013; in Tauranga Da Peng (stage name for Dong Chengpeng), Chinese comedian, filmmaker and TV show host; in Ji'an City, Jilin province Died: Dorothy Howel, 83, Brisith pianist and concerto composer. Major General Frank Crowther Roberts, 90, British Army officer and recipient of the Victoria Cross for heroism during World War One Major General Harold William Chase, 59, U.S. Marine Corps officer and Deputy Assistant Secretary of Defense from 1977 to 1980, died following a heart attack.
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.
GSH is the reduced form with a free thiol group, while GSSG is the oxidized disulfide-linked dimer. Most assays distinguish the two because their balance reflects redox conditions. The names are not interchangeable.