Everything below concerns thiol group. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Updated 2026-01-26. Numbers and descriptions here follow the published literature rather than marketing material.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | Refers to the reduced form |
| Molar mass | 307.32 g/mol | Calculated for the neutral molecule |
| Appearance | White crystalline powder | Often hygroscopic; protect from moisture |
| Water solubility | Soluble in water | Reported values vary with purity and form |
| Alternative names | GSH, reduced glutathione | GSH specifies the thiol form |
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.
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.
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.
Glutathione synthesis proceeds in two ATP-dependent steps catalyzed by glutamate-cysteine ligase and glutathione synthetase. The first step joins glutamate and cysteine to form gamma-glutamylcysteine and is generally rate-limiting. The second step adds glycine to complete the tripeptide. Cysteine availability, feedback inhibition by glutathione, and oxidative conditions influence flux through this pathway. The pathway is conserved across many organisms, and degradation by gamma-glutamyl transpeptidase and related peptidases recycles amino acids for new synthesis.
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.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. Its glutamate-cysteine linkage uses the gamma-carboxyl group of glutamate, a feature that resists standard peptidases. The cysteine residue provides a thiol group, which gives the molecule its reducing character. In cells, glutathione is often the most abundant small-molecule thiol, with concentrations varying widely by tissue and compartment. It exists mainly in a reduced form called GSH, while oxidation produces a disulfide-linked dimer called GSSG.
The carnitine shuttle is a biochemical reaction used to transport long chain fatty acids (LCFAs) from the cytosol into the matrix of the mitochondria so that they may be metabolized. While some fatty acids can, long chain fatty acids cannot pass through the mitochondrial membrane. However, carnitine (specifically its stereoisomer l-carnitine) can. The shuttle utilizes this to its advantage by attaching the LCFAs to carnitine. This new acyl-carnitine can pass through the membrane, after which it is split, with the newly separated carnitine being sent back out to shuttle more LCFAs, and the newly separated LCFAs undergoing beta oxidation to release their energy. The carnitine shuttle is an example of an antiporter system, and is a part of the broader class of metabolic reactions that constitute lipid metabolism. It is a highly conserved system found primarily in animals/some eukaryotes, although bacteria and plants still use carnitine for other things such as being an osmoprotectant, or being and electron acceptor in the electron transport chain. The shuttle system is implicated in many metabolic disorders, in the form of deficiencies of the enzymes in the system.
=== Surgery === Surgery (thyroidectomy to remove the whole thyroid or a part of it) is not extensively used because most common forms of hyperthyroidism are quite effectively treated by the radioactive iodine method, and because there is a risk of also removing the parathyroid glands, and of cutting the recurrent laryngeal nerve, making swallowing difficult, and even simply generalized staphylococcal infection as with any major surgery. Some people with Graves' may opt for surgical intervention. This includes those who cannot tolerate medicines for one reason or another, people who are allergic to iodine, or people who refuse radioiodine. A 2019 systematic review concluded that the available evidence shows no difference between visually identifying the nerve or utilizing intraoperative neuroimaging during surgery, when trying to prevent injury to the recurrent laryngeal nerve during thyroid surgery. If people have toxic nodules, treatments typically include either the removal or injection of the nodule with alcohol.
=== Malachite green === Malachite green (also known as diamond green B or victoria green B) can be used as a blue-green counterstain to safranin in the Gimenez staining technique for bacteria. It can also be used to directly stain spores.
Sources: en.wikipedia.org
=== Metabolic detoxification === An animal's metabolism can produce harmful substances which it can then make less toxic through reduction, oxidation (collectively known as redox reactions), conjugation and excretion of molecules from cells or tissues. This is called xenobiotic metabolism. Enzymes that are important in detoxification metabolism include cytochrome P450 oxidases, UDP-glucuronosyltransferases, and glutathione S-transferases. These processes are particularly well-studied as part of drug metabolism, as they influence the pharmacokinetics of a drug in the body.
== Structure == MHC class I molecules are heterodimers that consist of two polypeptide chains, α and β2-microglobulin (B2M). The two chains are linked noncovalently via interaction of B2M and the α3 domain. Only the α chain is polymorphic and encoded by a HLA gene, while the B2M subunit is not polymorphic and encoded by the beta-2 microglobulin gene. The α3 domain is plasma membrane-spanning and interacts with the CD8 co-receptor of T-cells. The α3-CD8 interaction holds the MHC I molecule in place while the T cell receptor (TCR) on the surface of the cytotoxic T cell binds its α1-α2 heterodimer ligand, and checks the coupled peptide for antigenicity. The α1 and α2 domains fold to make up a groove for peptides to bind. MHC class I molecules bind peptides that are predominantly 8-10 amino acid in length (Parham 87), but the binding of longer peptides have also been reported. While a high-affinity peptide and the B2M subunit are normally required to maintain a stable ternary complex between the peptide, MHC I, and B2M, under subphysiological temperatures, stable, peptide-deficient MHC I/B2M heterodimers have been observed. Synthetic stable, peptide-receptive MHC I molecules have been generated using a disulfide bond between the MHC I and B2M, named "open MHC-I".
Some Western powers also disapproved of Cuban linkage; for example, the French government issued the statement that it was inappropriate "the Namibian people should serve as hostages" to broader US foreign policy goals. The Cuban government interpreted linkage as further proof that South Africa was a foreign policy pawn of the US, and believed it to be part of a wider diplomatic and military offensive by the Reagan administration against Cuban interests worldwide. Botha called on other African states and Western nations to back his demands: "say to the Cubans 'go home' and say to the Russians 'go home', and the minute this happens I will be prepared to settle all our military forces inside South Africa". Botha also assured the UN that he would take steps to prepare South West Africa for independence "as long as there are realistic prospects of bringing about the genuine withdrawal of Cuban troops from Angola". The linkage of Namibian independence to the Cuban presence in Angola proved controversial, but it did involve the two Cold War superpowers—the US and the Soviet Union— in a joint mediation process for resolving the South African Border War at the highest level. In September 1982 Crocker met with Soviet Deputy Foreign Minister Leonid Ilichev for talks on the issue of Cuban-Namibian linkage. His deputy, Frank G. Wisner, held a series of parallel discussions with the Angolan government. Wisner promised that the US would normalise diplomatic and economic relations with Angola in the event of a Cuban withdrawal.
Sources: en.wikipedia.org
Russia claimed to have taken the village of Umanske, 30 kilometers northwest of Donetsk. Russian officials claimed that nine people were injured in Ukrainian drone attacks and shelling in Belgorod and Kursk Oblasts.
=== Ultraviolet === Ultraviolet light causes progressive damage to human skin and erythema even from small doses. This is mediated by genetic damage, collagen damage, as well as destruction of vitamin A and vitamin C in the skin and free radical generation. Ultraviolet light is also known to be a factor in formation of cataracts. Ultraviolet radiation exposure is strongly linked to incidence of skin cancer.
Braegen-02 is a small-molecule drug which acts as a potent and selective agonist of the tropomyosin receptor kinase B (TrkB). It is commonly referred to as CF3CN due to the CF3 and CN groups in its chemical structure, but this may cause confusion with the unrelated chemical trifluoroacetonitrile which has the chemical formula CF3CN. As with many TrkB agonists it was derived through modification of the natural product TrkB agonist 7,8-dihydroxyflavone, but it is more potent than earlier derivatives such as R13. It is under development as a potential treatment for neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease.
== Buffers == Buffers in gel electrophoresis are used to provide ions that carry a current and to maintain the pH at a relatively constant value. These buffers have plenty of ions in them, which is necessary for the passage of electricity through them. Something like distilled water or benzene contains few ions, which is not ideal for the use in electrophoresis. There are a number of buffers used for electrophoresis. The most common being, for nucleic acids Tris/Acetate/EDTA (TAE), Tris/Borate/EDTA (TBE). Many other buffers have been proposed, e.g. lithium borate (LB), (which is rarely used based on Pubmed citations), isoelectric histidine, pK matched Good's buffers, etc.; in most cases the purported rationale is lower current (less heat) matched ion mobilities, which leads to longer buffer life. Borate is problematic as borate can polymerize or interact with cis diols such as those found in RNA. TAE has the lowest buffering capacity, but provides the best resolution for larger DNA. This means a lower voltage and more time, but a better product. LB is relatively new and is ineffective in resolving fragments larger than 5 kbp; However, with its low conductivity, a much higher voltage could be used (up to 35 V/cm), which means a shorter analysis time for routine electrophoresis. As low as one base pair size difference could be resolved in 3% agarose gel with an extremely low conductivity medium (1 mM Lithium borate).
Sources: en.wikipedia.org
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.
It reflects the balance between oxidant exposure and antioxidant capacity. The ratio is not a direct clinical diagnosis and depends on the tissue and sample method.
No. It also participates in detoxification, amino acid transport, and protein modification. Its roles vary by cell type and compartment.
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.