If you have been reading about thiol and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-05-22. Where a claim depends on a specific study, the study is described rather than over-claimed.
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 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.
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.
| 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 |
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 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.
Biosynthesis proceeds in two ATP-dependent steps. First, glutamate-cysteine ligase joins glutamate and cysteine. Second, glutathione synthetase adds glycine to the intermediate. The pathway is regulated by cysteine availability, enzyme expression, and feedback inhibition by glutathione itself. Liver tissue has a particularly high capacity for synthesis and export. Because the molecule is made inside cells, circulating glutathione reflects a balance of release, uptake, and breakdown rather than simple dietary supply.
Functionally, glutathione supports redox balance by donating electrons and becoming oxidized. It also serves as a cofactor for enzymes such as glutathione peroxidases and glutathione S-transferases. These enzymes participate in peroxide reduction and in conjugation reactions that help process reactive molecules. Separate from antioxidant roles, glutathione can modify protein cysteines through S-glutathionylation, influencing enzyme activity and signaling. Research continues to examine how these chemical roles translate into whole-organism effects.
Clinicians use drug detoxification to reduce or relieve withdrawal symptoms while helping an addicted person adjust to living without drug use. Drug detoxification does not aim to treat addiction but rather represents an early step within long-term treatment. Detoxification may be achieved drug-free or may use medications as an aspect of treatment. Often drug detoxification and treatment will occur in a community program that lasts several months and takes place in a residential setting rather than in a medical center. Drug detoxification varies depending on the location of treatment, but most detox centers provide treatment to avoid the symptoms of physical withdrawal from alcohol and from other drugs. Most also incorporate counseling and therapy during detox to help with the consequences of withdrawal.
=== Eugenics === Pauling supported a limited form of eugenics by suggesting that human carriers of defective genes be given a compulsory visible mark – such as a forehead tattoo – to discourage potential mates with the same defect, in order to reduce the number of babies with diseases such as sickle cell anemia.
In addition, legal counsel to the president Harriet Miers and deputy chief of staff to the president Joshua Bolten were both found in contempt of Congress. In 2010, the Justice Department investigator concluded that though political considerations did play a part in as many as four of the attorney firings, the firings were "inappropriately political" but not criminal. According to the prosecutors, there was insufficient evidence to pursue prosecution for any criminal offense.
Sources: en.wikipedia.org
== History == The US Food and Drug Administration (FDA) approved taletrectinib based on evidence from 270 participants with ROS1-positive NSCLC that had spread beyond the lungs who received taletrectinib 600 mg orally once daily, enrolled in two clinical trials: TRUST-I (NCT04395677) or TRUST-II (NCT04919811). The TRUST-I trial was conducted exclusively in China and the TRUST-II trial was conducted globally in North America (United States and Canada), Europe (France, Italy, Spain, and Poland), and Asia (China, Japan, and South Korea). The efficacy of taletrectinib to treat ROS1-positive non-small cell lung cancer was evaluated in participants with locally advanced or metastatic, ROS1-positive non-small cell lung cancer enrolled in two multi-center, single-arm, open-label clinical trials, TRUST-I (NCT04395677) and TRUST-II (NCT04919811). The efficacy population included 157 participants (103 in TRUST-I; 54 in TRUST-II) who were naïve to treatment with a ROS1 tyrosine kinase inhibitor (TKI) and 113 participants (66 in TRUST-I; 47 in TRUST-II) who had received one prior ROS1 tyrosine kinase inhibitor. Participants may have received prior chemotherapy for advanced disease. The safety of taletrectinib was evaluated in 352 participants (337 with non-small cell lung cancer and 15 with other solid tumors) who received at least one 600 mg dose of taletrectinib.
When Augustus became sole ruler in 31 BC, he disbanded about half of the over 50 legions then in existence. The remaining 28 legions became the core of the early Imperial army of the Principate (27 BC – AD 284), most lasting over three centuries. Augustus and his immediate successors transformed legions into permanent units, staffed by entirely career soldiers on standard 25-year terms. During the Dominate period (near the end of the Empire, 284–476), legions were also professional, but are little understood due to scarcity of evidence compared to the Principate. What is clear is that late legions were radically different in size, structure, and tactical role from their predecessors, despite several retaining early period names. This was the result of the military reforms of Emperors Diocletian and Constantine I, and of further developments during the 4th century. The legions were identified by Roman numerals, though the spelling sometimes differed from the modern standard. For example, in addition to the spellings "IV", "IX", "XIV", "XVIII" and "XIX", the respective spellings "IIII", "VIIII", "XIIII", "XIIX" and "XVIIII" were commonly used. Legions also bore a cognomen or nickname. Neither a legion's number or cognomen were likely unique enough to identify it, so the combination of the two is usually needed to identify a specific legion. For example, both Legio III Cyrenaica and Legio III Gallica were distinct, long-standing legions of the late Republic and Imperial periods.
=== Genome evolution === The bowfin genome contains an intact ParaHox gene cluster, similar to the bichir and most other vertebrates. This is in contrast, however, with teleost fish, which have a fragmented ParaHox cluster, probably because of a whole genome duplication event in their lineage. The presence of an intact ParaHox gene cluster suggests that bowfin ancestors separated from other fish before the last common ancestor of all teleosts appeared. Bowfin are thus possibly a better model to study vertebrate genome organization than common teleost model organisms such as zebrafish.
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 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.