This is a working overview of Thiol, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2026-08-01 and is reviewed periodically as new material appears.
In cells, glutathione helps maintain the reducing environment of the cytosol and supports enzymes that counteract reactive oxygen species. It acts as a cofactor for glutathione peroxidases, which reduce hydrogen peroxide and lipid peroxides, and for glutathione S-transferases, which conjugate electrophiles. The ratio of GSH to GSSG is often used as an indicator of oxidative stress, although the ratio can vary by compartment and cell type. Glutathione also stores cysteine, an amino acid that can be limiting for protein synthesis and antioxidant defense.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | For reduced glutathione; the oxidized dimer has two sulfur atoms. |
| Molar mass | 307.32 g/mol | Calculated for the reduced form. |
| Appearance | White to off-white crystalline powder | Typical for solid reagent; solutions are usually colorless. |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar organic solvents. |
| Typical storage | -20 °C, desiccated, protected from light | Limits oxidation, moisture uptake, and degradation. |
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.
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 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.
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.
Two conserved cysteines coordinate one Fe ion while the other Fe ion is coordinated by two conserved histidines. The 2Fe-2S cluster is bound in the highly conserved C-terminal region of the Rieske subunit.
== History == The method of thermospray ionization was first introduced by a patent evidenced as early as 1983, and described in further detail by a patent published on March 8, 1988. Inventors Marvin L. Vestal and Calvin R. Blakley proposed an ion vapor source for mass spectrometry of liquids under a US Grant from the Department of Health, Education, and Welfare. The proposed method detailed a coupling device between liquid chromatographic columns and various methods of detection for gaseous samples; like mass spectrometry, electron capture, atomic adsorption, etc. Four different representations of the thermospray vaporizer were presented in the 1988 patent – UA4730111A. Nonvolatile, ionic, and thermally labile solutes were investigated with the various control systems on the vaporizers to achieve partial vaporization.
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== Record and specimen retention == CLIA and the College of American Pathologists (CAP) have written policies for the minimum period that laboratories should keep laboratory records and materials, with some examples as follows:
For example, a CMAJ article noted that only two case reports and one small case series existed at the time of writing, and guidance documents typically state that micro-dosing is not yet a fully evidence-based alternative compared with standard induction. Furthermore, the phrase "without precipitating withdrawal" should be understood as "typically less likely to precipitate withdrawal" rather than guaranteed to avoid it. Clinicians adopting this method must do so with caution, informed consent, and close monitoring — particularly because many of the studies are small, heterogeneous, and variable in protocol.
Sources: en.wikipedia.org
=== Approval === It is approved to treat complicated skin and soft tissue infections (cSSTI), complicated intra-abdominal infections (cIAI), and community-acquired bacterial pneumonia (CAP) in individuals 18 years and older. In the United Kingdom it is approved in adults and in children from the age of eight years for the treatment of complicated skin and soft tissue infections (excluding diabetic foot infections) and complicated intra-abdominal infections in situations where other alternative antibiotics are not suitable.
"For exceptionally meritorious service as Indian Defense and Military Attache to United States from 29 July 2019 to 17 Oct 2022". In 2023, Commodore Adrian C Fryer Royal Navy (UK). For exceptionally meritorious service and leadership as Deputy Commander and Commander, Combined Maritime Forces.
In an attempt to compensate for the exogenous increase in androgens, the body may reduce testosterone production via testicular atrophy and inhibition of gonadotropic activity. Unlike some AASs, oxandrolone does not generally cause gynecomastia because it is not aromatized into estrogenic metabolites. However, although no reports of gynecomastia were made in spite of widespread use, oxandrolone was reported in a publication in 1991 to have been associated with 33 cases of gynecomastia in adolescent boys treated with it for short stature. The gynecomastia developed during oxandrolone therapy in 19 of the boys and after the therapy was completed in 14 of the boys, and 10 of the boys had transient gynecomastia, while 23 had persistent gynecomastia that necessitated mastectomy. Though transient gynecomastia is a natural and common occurrence in pubertal boys, the gynecomastia associated with oxandrolone was of a late/delayed onset and was persistent in a high percentage of the cases. As such, the researchers stated, "although oxandrolone cannot be implicated as stimulatory [in] gynecomastia", a possible relationship should be considered in clinicians using oxandrolone in adolescents for growth stimulation.
=== Translational repression === The translation initiation factor eIF4E is tightly regulated by the fragile X mental retardation protein (FMRP), which controls the translation of specific mRNAs at synapses. FMRP interacts with CYFIP1, which directly binds eIF4E at a domain structurally analogous to those found in canonical 4E-binding proteins such as EIF4EBP1, EIF4EBP2, and EIF4EBP3. This interaction competitively inhibits eIF4G binding, thereby blocking assembly of the eukaryotic translation initiation complex and repressing translation. The FMRP–CYFIP1–eIF4E complex is further stabilized by dendritically localized, non-coding RNAs such as BC1, which enhance FMRP-CYFIP1 interactions and mediate recruitment to specific target mRNAs. This repressive complex is responsive to neuronal stimulation. Synaptic activity promotes the dissociation of CYFIP1 from eIF4E, thereby allowing eIF4G to bind and initiate translation. This mechanism enables dynamic, activity-dependent regulation of protein synthesis at the synapse, contributing to processes such as synaptic plasticity and learning. Since eIF4E is an initiation factor that is relatively low in abundance, eIF4E can be controlled at multiple levels. Regulation of eIF4E may be achieved at the levels of transcription, RNA stability phosphorylation, subcellular localization and partner proteins.
Sources: en.wikipedia.org
1888: American chemist Josephine Silone Yates was appointed head of the Department of Natural Sciences at Lincoln Institute (later Lincoln University), becoming the first black woman to head a college science department. 1889: American astronomer Antonia Maury discovered the second spectroscopic binary, Beta Aurigae, and calculated its orbital period. 1889: American geologist Mary Emilie Holmes became the first female Fellow of the Geological Society of America.
13 March – Five people are taken to hospital for treatment after a bus crashes into a high rise block of flats in Paisley, Glasgow. 14 March – The Scottish Parliament Corporate Body finds Michael Matheson in breach of the Ministerial Code over his £11,000 iPad bill. Mountaineer Anna Wells becomes the first woman to reach the top of all of Scotland's 282 Munros in one winter season. 15 March – Following trial and conviction at the High Court in Glasgow, double murderer Peter Duffy is sentenced to at least 30 years in prison for the murder of his wife, Emma Baillie, and brother, John-Paul Duffy, in separate incidents in Coatbridge in 2022. 17 March – HMP Kilmarnock becomes the first privately run prison in Scotland to pass into the ownership of the Scottish Prison Service after its contract with Serco comes to an end. 19 March – Scottish Prison Service director Allister Purdie gives evidence to the Scottish COVID-19 Inquiry, and apologises to the family of Callum Inglis, who died at Addiewell Prison during the pandemic, after his family learned of the death through word of mouth before they were told formally by prison authorities. 21 March – The Scottish Parliamentary Corporate Body confirms that members of Scottish Parliament staff will no longer be allowed to wear rainbow lanyards, or any other badge or jewellery associated with social issues, while at Holyrood. The Wildlife Management and Muirburn (Scotland) Bill passes its final vote in the Scottish Parliament.
At the highest assessed dose in castrated male rats, levator ani weight was increased to around 140% of that of gonadally intact controls, whereas prostate weight was only increased to around 45% of that of intact controls. The tissue selectivity of LGD-4033 was independent of local tissue drug concentration, suggesting that its selectivity was intrinsic. The muscle-stimulating effects of LGD-4033 have also been confirmed in humans in preliminary clinical trials. The data also allow comparison between different SARMs and other AR agonists. In a phase 1 clinical trial in 76 healthy young men, 1 mg/day LGD-4033 increased lean body mass by 1.2 kg after 3 weeks of treatment. For comparison, enobosarm, another SARM, increased lean body mass by 1.3 kg at a dose of 3 mg/day after 12 weeks in healthy elderly men and postmenopausal women. It was concluded that the employed dose of LGD-4033 produced similar increases in lean body mass compared to enobosarm despite a substantially shorter treatment period. In a phase 2 clinical trial in 108 women and men with hip fracture, LGD-4033 increased lean body mass by 4.8% at 0.5 mg/day, 7.2% at 1 mg/day, and 9.1% at 2 mg/day after 12 weeks of treatment. For comparison, lean body mass with enobosarm 3 mg/day after the same time period of 12 weeks increased by about 0.30% at 0.1 mg/day, 0.40% at 0.3 mg/day, 1.2% at 1 mg/day, and 3.1% at 3 mg/day, with only the latter change achieving statistical significance.
When a growth factor binds to the extracellular domain of an RTK, its dimerization is triggered with other adjacent RTKs. Dimerization leads to a rapid activation of the protein's cytoplasmic kinase domains, the first substrate for these domains being the receptor itself. The activated receptor, as a result, then becomes autophosphorylated on multiple specific intracellular tyrosine residues.
yr) by detecting the 39K→38Ar→37Ar decay chain. Above the electroweak scale ΛEW (corresponding to the vacuum expectation value of the Higgs field, around 246 GeV), where Standard Model unification occurs, the three fundamental forces have comparable couplings, suggesting unification in Grand Unified Theories (GUTs). Historical models like Pati–Salam model (1973), unifying quarks/leptons and Georgi–Glashow model (1974), unifying all forces and particles/antiparticles, predict B violation via superheavy gauge bosons MX. The natural GUT energy scale ΛGUT is where SM gauge couplings converge, ~1015 GeV. This value is approximately thirteen orders of magnitude higher than the electroweak scale, or more than eleven orders of magnitude higher than the energy achievable in experiments conducted at particle accelerators. However, at these energies the estimation of proton decay lifetime is around 1029–1031 yr, within reach of dedicated experiments: when GUTs were proposed, the experimental limits were around 1030 yr (for decay modes which produce 𝜇 →𝑒 decays). These considerations strongly motivated proton decay searches. In 1981 was published the first limit by a water Cherenkov detector at the Homestake gold mine, looking for the production and detection of a decaying muon following a nucleon decay event:
Sources: en.wikipedia.org
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.
It is synthesized in the body from amino acids, so it is not classified as an essential dietary nutrient for most people. Dietary and supplemental forms are studied for their effects on tissue levels and health markers. Evidence varies by population and outcome.
The phrase highlights its high intracellular concentration and its role in several antioxidant and detoxification reactions. It is not the only antioxidant, and the term can oversimplify its functions. Scientific descriptions usually specify the pathway or enzyme involved.
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.