A practical reference on thiol: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-09-14 and is reviewed periodically as new material appears.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced glutathione (GSH); oxidized form differs by disulfide linkage. |
| Molar mass | 307.32 g/mol | Calculated for the reduced tripeptide. |
| Appearance | White to off-white crystalline powder | Typical laboratory reagent description. |
| Solubility | Soluble in water | Aqueous solutions are acidic; solubility depends on pH and salt form. |
| CAS Registry Number | 70-18-8 | Refers to reduced L-glutathione; oxidized form has a different number. |
Early lichenologists later reclassified the species in different genera. For instance, Erik Acharius (1803) referred to it as Parmelia parietina in his work Methodus, and Giuseppe De Notaris (1847) listed it as Physcia parietina. Johannes M. Norman (1852) treated it under Teloschistes (a related genus of orange-colored lichens), calling it Teloschistes parietinus. The modern genus Xanthoria was established by Theodor Fries. In 1860, he formally recombined the species as Xanthoria parietina. In his treatment, Fries recognized a distinct form, which he called Xanthoria aureola, distinguishing it from the more common form of X. parietina. He described aureola as a primary and fundamental form of the species, particularly prevalent in Arctic regions, differing from typical X. parietina in its color, rigid thallus, and preference for exposed habitats. Fries also cited Acharius, who considered aureola an intermediate between Xanthoria elegans (now Rusavskia elegans) and X. parietina. These distinctions may have contributed to later taxonomic interpretations that recognized Xanthoria aureola as a separate species. Xanthoria parietina is the type species of the genus Xanthoria. The designated lectotype for Xanthoria parietina is the illustration cited by Linnaeus from Dillenius (1742). Due to its reclassification across different genera, Xanthoria parietina has accumulated many synonyms in the literature. In addition to generic transfers, various infraspecific taxa (forms, varieties, or subspecies) have been described, particularly regarding morphological variants.
== Career == Bigbie attended Ball State University. In 1998, he played collegiate summer baseball with the Wareham Gatemen of the Cape Cod Baseball League. Bigbie was drafted by the Baltimore Orioles in the 1st round (21st pick overall) of the 1999 Major League Baseball amateur draft and played over four years (2001–2005) for the Orioles before being traded during the 2005 season to the Colorado Rockies. Bigbie played the remainder of 2005 season for the Rockies. On December 8, 2005, the Rockies traded him and Aaron Miles to the St. Louis Cardinals for pitcher Ray King. On February 2, 2007, he signed a minor league deal with the Los Angeles Dodgers. Bigbie exercised a free agent option in his contract on June 1, 2007, and on June 11 signed a minor league contract with the Braves. During his six-year career, he posted a .268 batting average, hitting 31 home runs and amassing 322 hits in 375 games. Bigbie is an average fielder, but has an above-average arm. He batted .240 in 2006 with the Cardinals, also posting only 1 RBI, in 17 games. In December 2007, it was announced that he had agreed to a deal to play for the Yokohama Bay Stars of the Nippon Professional Baseball (NPB). Bigbie made a comeback for the 2010 season, playing for the Edmonton Capitals of the Golden Baseball League. Bigbie was named the DH for Baseball America's 2010 All-Independent Leagues Team.
Other prominent Han Chinese who have made notable contributions the development and growth of modern science and technology include the medical researcher, physician, and virologist David Ho, who was one of the first scientists to propose that AIDS was caused by a virus, thus subsequently developing combination antiretroviral therapy to combat it. In recognition of his medical contributions, Ho was named Time magazine Person of the Year in 1996. The medical researcher and transplant surgeon Patrick Soon-Shiong is the inventor of the drug Abraxane, which became known for its efficacy against lung, breast, and pancreatic cancer. Soon-Shiong is also well known for performing the first whole-pancreas transplant and he developed and first performed the experimental Type 1 diabetes-treatment known as encapsulated-human-islet transplant, and the "first pig-to-man islet-cell transplant in diabetic patients." The physician and physiologist Thomas Ming Swi Chang is the inventor of the world's first artificial cell made from a permeable plastic sack that would effectively carry hemoglobin around the human circulatory system. Chang is also noteworthy for his development of charcoal-filled cells to treat drug poisoning in addition to the discovery of enzymes carried by artificial cells as a medical tool to correct the faults within some metabolic disorders.
=== Chemical === Neptunium has five ionic oxidation states ranging from +3 to +7 when forming chemical compounds, which can be simultaneously observed in solutions. It is the heaviest actinide that can lose all its valence electrons in a stable compound. The most stable state in solution is +5, but the valence +4 is preferred in solid neptunium compounds. Neptunium metal is very reactive. Ions of neptunium are prone to hydrolysis and formation of coordination compounds.
Sources: en.wikipedia.org
=== Woodhouse Sixth Form College === Daisy Edgar-Jones, actress Johann Hari, journalist and writer Julia Hartley-Brewer, journalist, broadcaster and presenter Naomie Harris, actress David Hirsh, sociologist Jesse Honey, Mastermind winner 2010 and World Quiz Champion 2012 Michael McIntyre, stand-up comedian Ali Jawad, Paralympic powerlifter (silver medallist, Rio 2016) Robert Rinder, known as "Judge Rinder", barrister and television personality Stephen Bush, journalist Antigoni Buxton, Love Island participant and singer
=== Medical food === Glutamine is marketed as medical food and is prescribed when a medical professional believes a person in their care needs supplementary glutamine due to metabolic demands beyond what can be met by endogenous synthesis or diet.
=== Importance of physiochemical properties === For drug delivery systems to bypass the blood brain barrier, modifications of physiochemical properties can enhance safety and efficacy. Size, surface charge, and lipophilicity play a major role in substance bypassing the blood brain barrier. Smaller, positively charged, or more lipophilic molecules enhance efficacy of nose-to-brain delivery. Decrease in delivery system size increases permeation. As the membrane is negatively charged, a particle with positive surface charge interacts electrostatically which enhances bioadhesion. Carriers with more lipophilicity exert better mucoadhesion and residence time. Drug system pH, solubility, and hydrogen bonding potential are other physiochemical properties which should be evaluated.
== Biosynthesis == Biosynthesis pathway of fumitremorgin pathway involves several different enzymes. FtmA is a nonribosomal peptide synthase. Both FtmB and FtmH are prenyltransferase. Three different cytochrome P450 monooxygenases involved in the biosynthesis of fumitremorgin C are FtmC, FtmE, and FtmG. Furthermore, FtmD is proposed to function as the methyltransferase. The synthesis starts with the formation of brevianamide F. FtmA catalyzes the nonribosomal peptide synthesis (NRPS) of this diketopiperazine product from two amino acids, L-tryptophan and L-proline. Then, another enzyme, FtmB, prenylates the product to form tryprostatin B. At this point, there are two separate pathways. FtmE may cyclize tryprostatin B to form demethoxyfumitremorgin C, or FtmC may oxidize tryprostatin B to form desmethyltrprostatin A by adding a hydroxyl group to the C-6 of the indole ring. The later pathway is followed by methylation to form tryprostatin A. The enzyme that catalyzes this methylation reaction has not been fully identified, but FtmD is suspected to be the plausible candidate. Then, the cyclization of tryprostatin A produces fumitremorgin C by forming the C-N bond by FtmE. The subsequent hydroxylation of fumitremorgin C takes place at C-12 and C-13 to form 12α, 13α-dihydroxyfumitremorgin C by FtmG. Fumitremorgin B is formed by another prenyltransferase, FtmH, that prenylates at N-1 of the indole ring (N-vinyl rather than N-prenyl incorrectly shown in the scheme below).
=== Sexual deviance === CPA is used as an antiandrogen and form of chemical castration in the treatment of paraphilias and hypersexuality in men. It is used to treat sex offenders. The medication is approved in more than 20 countries for this indication and is predominantly employed in Canada, Europe, and the Middle East. CPA works by decreasing sex drive and sexual arousal and producing sexual dysfunction. CPA can also be used to reduce sex drive in individuals with inappropriate sexual behaviors, such as people with intellectual disability and dementia. The medication is also used to reduce sexual behavior diagnosed as self-harmful, such as masochism. CPA has comparable effectiveness to medroxyprogesterone acetate in suppressing sexual urges and function but appears to be less effective than GnRH modulators like leuprorelin and has more side effects. High-dose CPA significantly decreases sexual fantasies and sexual activity in 80 to 90% of men with paraphilias. In addition, it has been found to decrease the rate of reoffending in sex offenders from 85% to 6%, with most of the reoffenses being committed by individuals who did not follow their CPA treatment prescription. It has been reported that in 80% of cases, 100 mg/day CPA is adequate to achieve the desired reduction of sexuality, whereas in the remaining 20% of cases, 200 mg/day is sufficient. When only a partial reduction in sexuality is desired, 50 mg/day CPA can be useful.
Sources: en.wikipedia.org
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.
Glutathione is synthesized inside cells from amino acids rather than being classified as an essential dietary nutrient. Dietary sources can provide glutathione or its precursors, but digestion and absorption alter what reaches tissues. Research continues on how dietary intake relates to cellular glutathione levels.
The liver has high glutathione concentrations and uses the compound in conjugation and antioxidant reactions. These reactions are relevant to the processing of drugs, pollutants, and normal metabolic byproducts. Studies often examine liver glutathione as a marker of oxidative stress or detoxification capacity.
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.