The short version of thiol fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-01-17. Anything still debated is marked as such rather than presented as settled.
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 is a small tripeptide composed of glutamate, cysteine, and glycine, with the unusual gamma-glutamyl linkage between glutamate and cysteine. Its cysteine thiol group makes it a major non-enzymatic antioxidant in cells. The reduced form, GSH, predominates in most intracellular compartments, while the oxidized disulfide form, GSSG, is produced when GSH reduces reactive oxygen species. Intracellular concentrations often reach millimolar levels, whereas plasma concentrations are much lower, typically in the low micromolar range. This gradient reflects active synthesis, transport, and consumption rather than passive distribution.
Within cells, glutathione serves as a cofactor for glutathione peroxidases and glutathione S-transferases. These enzymes reduce hydrogen peroxide and organic peroxides or conjugate electrophilic compounds to the thiol group. The resulting conjugates can be exported and processed through mercapturic acid pathways. Glutathione also contributes to protein thiol homeostasis and to recycling of other antioxidants such as ascorbate. Its precise roles vary by tissue, and many regulatory effects observed in laboratory systems remain difficult to quantify in whole organisms.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It occurs in nearly all living cells, with highest concentrations in liver, kidney, and red blood cells, and exists in reduced (GSH) and oxidized disulfide (GSSG) forms. The cysteine thiol group enables reversible oxidation and reduction reactions. This property makes glutathione a central participant in cellular redox balance. The balance between these forms is often used as an indicator of oxidative stress.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Tripeptide of glutamate, cysteine, and glycine. |
| Molar mass | 307.32 g/mol | Calculated from the molecular formula. |
| Appearance | White to off-white powder | Typically crystalline or lyophilized solid. |
| Solubility | Soluble in water; insoluble in ethanol | Aqueous solutions are acidic and prone to oxidation. |
| Typical storage | -20 °C, desiccated, protect from light | Reduce exposure to oxygen and moisture. |
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.
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 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.
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.
Vasodilators are increased (such as nitric oxide and carbon monoxide) reducing afterload with compensatory increase in cardiac output, mixed venous oxygen saturation. Renin is increased (as well as sodium retention in kidneys) secondary to a fall in systemic vascular resistance. FibroTest is a biomarker for fibrosis that may be used instead of a biopsy. Other laboratory studies performed in newly diagnosed cirrhosis may include:
In critical illness, inflammation increases tanycyte D2 in the paraventricular nucleus (PVN) of the hypothalamus, leading to local tissue hyperthyroidism. There may also be decreased central D3. This causes negative feedback on the HPT axis, and therefore reduced TRH gene expression in the PVN. This is exemplified by the common NTIS phenotype of low TSH even in the face of peripheral hypothyroidism.
==== Context ==== The announcement of the new cabinet is an attempt to resolve a political crisis between Pedro Castillo and the Congress of the Republic. On 24 November 2022, President Castillo delivered a speech to the nation in which he announced that he accepted the resignation of Aníbal Torres and also the appointment of a new cabinet. The resigning Prime Minister wanted to provoke a vote of confidence in Congress so that it would analyze a constitutional reform project to annul Congress in order to trigger referendums, particularly on the Constituent Assembly, a historic project of Castillo's, but the vote of confidence was denied by the presidency of Congress, dominated by the centre-right and the right. In that same speech, Pedro Castillo evokes the interpretation of Congress's decision not to allow the vote of confidence desired by the President of the council as an "express refusal of confidence" and considers this cabinet change legitimate.
== Toxicity == SRTX-b and SRTX-a are highly lethal and cause cardiac arrest and death in mice within minutes of intravenous administration, LD50 for mice was detected for about 0.015 mg/kg body weight and LD50 0.3 mg/kg in case of SRTX-c.
The Mithridatic antidote is composed of fifty-four ingredients, no two of them having the same weight, while of some is prescribed one sixtieth part of one denarius. Which of the gods, in the name of Truth, fixed these absurd proportions? No human brain could have been sharp enough. It is plainly a showy parade of the art, and a colossal boast of science.
Sources: en.wikipedia.org
== Further reading == Savulescu, Julian; Bostrom, Nick (2009). Human enhancement. Oxford: Oxford University Press. ISBN 978-0-19-929972-0. Savulescu, Julian; ter Meulen, Ruud; Kahane, Guy (2011). Enhancing human capacities. Chichester: Wiley-Blackwell. ISBN 978-1-4051-9581-2. Michael Bess (2015). Our Grandchildren Redesigned: Life in the Bioengineered Society of the Near Future. Beacon Press. ISBN 978-0-8070-5217-4. Bateman, Simone; Gayon, Jean; Allouche, Sylvie; Goffette, Jérôme; Marzano, Michela (2015). Inquiring into Human Enhancement: Interdisciplinary and International Perspectives (1 ed.). London: Palgrave Macmillan. ISBN 978-1-137-53006-6. Edwards, Gary (2016). "Enhancement". Encyclopedia of Global Bioethics. Springer International Publishing. pp. 1121–1130. doi:10.1007/978-3-319-09483-0_172. ISBN 978-3-319-09483-0. Jotterand, Fabrice; Ienca, Marcello (2024). The Routledge Handbook of the Ethics of Human Enhancement. New York: Routledge. ISBN 978-0-367-61579-6.
=== Terminology === The word addiction derives from the Latin "addico", meaning "giving over" with both positive connotations (devotion, dedication) and negative ones (being enslaved to a creditor in Roman law). This dual meaning persisted in traditional English dictionaries, encompassing both legal surrender and personal devotion to habits. Later, the 19th century temperance movements narrowed the definition of addiction to just drug-related disease, ignoring behavioral addictions and the possibility of positive or neutral addictions. This restrictive view opposes the current understanding of addiction. Addiction and addictive behavior are polysemes denoting a category of mental disorders, of neuropsychological symptoms, or of merely maladaptive/harmful habits and lifestyles. A common use of the term addiction in medicine is for neuropsychological symptoms denoting pervasive/excessive and intense urges to engage in a category of behavioral compulsions or impulses towards sensory rewards (e.g., alcohol, betel quid, drugs, sex, gambling, video gaming). Addictive disorders or addiction disorders are mental disorders involving high intensities of addictions (as neuropsychological symptoms) that induce functional disabilities (i.e., limit subjects' social/family and occupational activities); the two categories of such disorders are substance-use addictions and behavioral addictions. The etymology of the term addiction throughout history has been misunderstood and has taken on various meanings associated with the word.
=== Depression === The primary use of trazodone is the treatment of unipolar major depression with or without anxiety. Data from open and double-blind trials suggest that the antidepressant efficacy of trazodone is comparable to that of amitriptyline, doxepin, and mianserin. Furthermore, trazodone has shown anxiolytic properties, low cardiotoxicity, and relatively mild side effects. Because trazodone has minimal anticholinergic activity, it was especially welcomed as a treatment for geriatric patients with depression when it first became available. Three double-blind studies reported trazodone had antidepressant efficacy similar to that of other antidepressants in geriatric patients. Unfortunately, a side effect of trazodone, orthostatic hypotension, may cause dizziness and increase the risk of falling. This may have devastating consequences for elderly patients. Therefore, this side effect, along with sedation, often makes trazodone less acceptable for this population compared to newer compounds that share its lack of anticholinergic activity (but not the rest of its side effect profile). Still, trazodone is often helpful for geriatric patients with depression who have severe agitation and insomnia. Trazodone is usually used at a dosage of 150 to 300 mg/day for the treatment of depression. Lower doses have also been used to augment other antidepressants or when initiating therapy. Higher doses, up to 600 mg/day, have been used in more severe cases of depression (in hospitalized patients, for example).
It is quite clear that the structure of the enzyme, to be specific the active site, is very important in understanding the mechanism of reaction. For this reason, Rees and colleagues studied the enzyme-ligand complex to get a clear answer for the role of the zinc ion. These studies found that, in free enzyme, the zinc coordination number is five; the metal center is coordinated with two imidazole Nδ1 nitrogens, the two carboxylate oxygens of glutamate-72, and a water molecule to form a distorted tetrahedral. However, once ligand binds at the active site of carboxypeptidase A, this coordination number can vary from five to six. When bound to dipeptide glycyl-L-tyrosine, the amino nitrogen of the dipeptide and the carbonyl oxygen replaced the water ligand. This would yield a coordination number of six for the zinc in the carboxypeptidase A- dipeptide glycyl-L-tyrosine complex. Electron density maps gave evidence that the amino nitrogen occupies a second position near glutamate-270. The closeness of these two residues would result in a steric hindrance preventing the water ligand from coordinating with zinc. This would result in a coordination number of five. Data for both are substantial, indicating that both situations occur naturally. There are two proposed mechanisms for the catalytic function of carboxypeptidase A. The first is a nucleophilic pathway involving a covalent acyl enzyme intermediate containing active site base Glu-270. Evidence for this anhydride intermediate is mixed; Suh and colleagues isolated what is assumed to by the acyl intermediate.
Sources: en.wikipedia.org
== Characteristics == The genome of C. xerosis is approximately 2.7 million base pairs long with over 2,000 genes encoding proteins and a high G+C content. C. xerosis was found to contain a series of plasmids, one of which confers resistance to common antibiotics such as chloramphenicol, kanamycin, streptomycin, and tetracycline and was named pTP10. This plasmid has since been introduced into Bacillus subtilis and modified to generate several vectors for molecular cloning purposes. In addition to having resistance to many antibiotics itself, at least one strain of C. xerosis also appears capable of producing antimicrobial compounds. These can inhibit bacteria and fungi, but the strength of antimicrobial activity by this strain depends on the carbon sources available. Also, a petroleum ether extract from C. xerosis was found to decrease the growth rate of tumors in mice, increasing their lifespan while being nontoxic to healthy mice. A study in 1967 confirmed the ability of several strains of C. xerosis to form single-layer "clumps" of cells around gas bubbles when cultures of the bacteria are suspended in buffer solutions at low temperatures with vigorous stirring. This property was attributed to cell surface proteins.
TURED has been shown to improve the volume of semen in men with ejaculatory duct obstruction leading to significant improvement in the fertility rate. Hormonal abnormalities caused by either primary or secondary hypogonadism can be treated with off-label use of oral clomiphene citrate which has been shown to increases the level of testosterone in the body. Administration of exogenous testosterone for the treatment of hypogonadism has shown to a have negative impact on the process of spermatogenesis. Abnormalities in the seminal vesicle and vas deferens usually don't respond well to surgeries or medications. In such situations, sperm can be extracted along with assisted reproductive technologies (ARTs) such as intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI) for successful conception. These procedures can be very costly.
=== Sales and usage === Sales of bicalutamide (as Casodex) worldwide peaked at US$1.3 billion in 2007, and it has been described as a "billion-dollar-a-year" drug prior to losing its patent protection starting in 2007. In 2014, despite the introduction of abiraterone acetate in 2011 and enzalutamide in 2012, bicalutamide was still the most commonly prescribed drug in the treatment of metastatic castration-resistant prostate cancer (mCRPC). Moreover, in spite of being off-patent, bicalutamide was said to still generate a few hundred million dollars in sales per year for AstraZeneca. Total worldwide sales of brand name Casodex were approximately US$13.4 billion as of the end of 2018.
Sniper Thomas Beckett is hired by NSA officials William Avery and Richard Addis to perform a covert operation to eliminate a suspected terrorist kingpin in the People's Republic of Vietnam who was providing support for Jemaah Islamiyah.
==== UPMC Whitfield ==== UPMC Whitfield is an 80-bed private hospital located in Waterford, Ireland. UPMC, which had operated a cancer center at the hospital since 2006, acquired the hospital on May 24, 2018.
Sources: en.wikipedia.org
GSH is the reduced, thiol-containing form of glutathione, while GSSG is the oxidized disulfide dimer formed when two GSH molecules react. Cells maintain a high GSH-to-GSSG ratio under normal conditions. A shift toward GSSG is often interpreted as oxidative stress, though sample handling can affect the measured ratio.
No. It is a tripeptide made from three amino acids: glutamate, cysteine, and glycine. The gamma-glutamyl bond is unusual and distinguishes it from typical peptide linkages.
Most ingested glutathione is broken down in the gastrointestinal tract into its constituent amino acids. Some formulations may protect it from digestion, but intact absorption and delivery to specific tissues remain uncertain. Research continues on precursors and delivery methods.
GSH is the reduced thiol form, while GSSG is the disulfide-linked oxidized dimer. The GSH:GSSG ratio is used as a redox indicator, though the ratio can vary with sample handling and cell type.