The short version of Thiol fits in a sentence. The long version — which is the one that helps — is below.
This page was last updated on 2026-06-29 and is reviewed periodically as new material appears.
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.
Storage conditions strongly influence glutathione stability. The solid reduced form is commonly kept desiccated at or below minus twenty degrees Celsius, protected from light and moisture. Aqueous solutions are less stable because the thiol group reacts with dissolved oxygen, and oxidation accelerates at neutral or alkaline pH. Acidic solutions and oxygen-free handling can slow degradation, but repeated freeze-thaw cycles should be avoided. Researchers often verify concentration before use, because apparent losses can arise from oxidation or water uptake.
Measuring glutathione in biological samples requires attention to oxidation and matrix effects. High-performance liquid chromatography with ultraviolet or fluorescence detection can separate reduced and oxidized forms after derivatization. Liquid chromatography with tandem mass spectrometry offers higher specificity and can quantify glutathione alongside related thiols. Because glutathione can oxidize during sample handling, many protocols use rapid acidification with metaphosphoric acid or sulfosalicylic acid. Internal standards help correct for losses during extraction and analysis.
Enzymatic recycling assays provide a complementary approach for total glutathione. In these methods, glutathione reductase reduces oxidized glutathione while a thiol-reactive reagent, such as 5,5'-dithiobis(2-nitrobenzoic acid), produces a colored product. The reaction cycles between reduced and oxidized forms, amplifying the signal. Spectrophotometric or fluorometric detection can then estimate concentration. Distinguishing reduced glutathione from glutathione disulfide often requires separate aliquots, masking agents, or chromatographic separation, and the choice affects reported values.
| 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 |
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.
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.
Glutathione is a small sulfur-containing peptide built from glutamic acid, cysteine, and glycine. Its distinctive feature is a gamma-glutamyl bond between glutamate's side-chain carboxyl group and cysteine's amino group. This linkage resists ordinary peptidases and helps the molecule remain stable inside cells. The reduced thiol form, often abbreviated GSH, is the dominant intracellular species. The oxidized disulfide dimer, GSSG, forms when two reduced molecules link through their cysteine sulfur atoms. The balance between these forms is a common redox indicator.
In living systems, glutathione occurs in millimolar concentrations in many cell types, while extracellular levels are generally much lower. The liver holds a substantial share of the body's total pool, and the molecule participates in reduction, detoxification, and amino acid transport. It also serves as a cofactor for enzymes such as glutathione peroxidase and glutathione S-transferase. Because the cysteine residue supplies a reactive thiol, glutathione can donate electrons and become oxidized. Cells regenerate reduced glutathione through glutathione reductase using NADPH.
A scar is the product of the body's repair mechanism after tissue injury. If a wound heals quickly within two weeks with new formation of skin, minimal collagen will be deposited and no scar will form. When the extracellular matrix senses elevated mechanical stress loading, tissue will scar, and scars can be limited by stress shielding wounds. Small full thickness wounds under 2mm reepithelize fast and heal scar free. Deep second-degree burns heal with scarring and hair loss. Sweat glands do not form in scar tissue, which impairs the regulation of body temperature. Elastic fibers are generally not detected in scar tissue younger than 3 months old. In scars, rete pegs are lost; through a lack of rete pegs, scars tend to shear easier than normal tissue. The endometrium, the inner lining of the uterus, is the only adult tissue to undergo rapid cyclic shedding and regeneration without scarring, shedding and restoring roughly inside a 7-day window on a monthly basis. All other adult tissues, upon rapid shedding or injury, can scar. Prolonged inflammation, as well as the fibroblast proliferation, can occur. Redness that often follows an injury to the skin is not a scar and is generally not permanent (see wound healing). The time it takes for this redness to dissipate may take years in severe cases, however. Scars form differently based on factors including: the location of the injury on the body, the age of the person who was injured, and the severity of the injury. Skin scars occur when the dermis (the deep, thick layer of skin) is damaged.
=== Reactivity === Thorium is a highly reactive and electropositive metal. With a standard reduction potential of −1.90 V for the Th4+/Th couple, it is somewhat more electropositive than zirconium or aluminium. Finely divided thorium metal can exhibit pyrophoricity, spontaneously igniting in air. When heated in air, thorium turnings ignite and burn with a brilliant white light to produce the dioxide. In bulk, the reaction of pure thorium with air is slow, although corrosion may occur after several months; most thorium samples are contaminated with varying degrees of the dioxide, which greatly accelerates corrosion. Such samples slowly tarnish, becoming grey and finally black at the surface. At standard temperature and pressure, thorium is slowly attacked by water, but does not readily dissolve in most common acids, with the exception of hydrochloric acid, where it dissolves leaving a black insoluble residue of ThO(OH,Cl)H. It dissolves in concentrated nitric acid containing a small quantity of catalytic fluoride or fluorosilicate ions; if these are not present, passivation by the nitrate can occur, as with uranium and plutonium.
== Research Applications == In the research field, pramlintide has been experimented with and used as a potential treatment drug. Pramlintide has demonstrated its ability to decrease amyloid beta plaques in Alzheimer's disease mouse models.
The bill, if passed, would have allowed Congress, by a concurrent resolution, to require an 11-member commission to conduct an examination of the president and report the findings. In April 2017, forensic psychiatrist Bandy X. Lee hosted a meeting at Yale University medical school regarding the ethics of discussing Trump's mental health. In October 2017, Lee published The Dangerous Case of Donald Trump, containing essays from 27 psychologists, psychiatrists, and mental health professionals on the "clear and present danger" that Trump's mental health poses to the "nation and individual well being". They argued that the president's issues affected the mental health of the United States population, and that he placed the country at grave risk of war because of his pathological traits. They asserted that Trump exhibited narcissistic personality disorder, "extreme present hedonism", and bullying. Carlos Lozada, writing for The Washington Post, considered these conclusions "compelling", but also noted that the book contributors were writing from their own political perspectives and that other mental health professionals held differing views. Lee and others contended that Trump's presidency represented an emergency allowing, or even requiring, psychiatrists to make an exception to the APA's Goldwater rule, which holds that it is unethical for members of the APA to give professional opinions about public figures without having examined them in person and without having obtained their consent.
== Term == The term thrombocyte (clot cell) came into use in the early 1900s and is sometimes used as a synonym for platelet; but not generally in the scientific literature, except as a root word for other terms related to platelets (e.g. thrombocytopenia meaning low platelets). The term thrombocytes is proper for mononuclear cells found in the blood of non-mammalian vertebrates: they are the functional equivalent of platelets, but circulate as intact cells rather than cytoplasmic fragments of bone marrow megakaryocytes. In some contexts, the word thrombus is used interchangeably with the word clot, regardless of its composition (white, red, or mixed). In other contexts it is used to contrast a normal from an abnormal clot: thrombus arises from physiologic hemostasis, thrombosis arises from a pathologic and excessive quantity of clot. In a third context it is used to contrast the result from the process: thrombus is the result, thrombosis is the process.
Sources: en.wikipedia.org
=== Light === Herbarium specimens are sensitive to visible light and ultraviolet radiation, which can cause fading of biological pigments (fading or shifts in color) and/or damage to chemical bonds (weakened or embrittled).
=== Mediterranean and ancient Greece === Among the Hellenes, Egyptians, and others, vegetarianism had medical or ritual purification purposes. Vegetarianism was also practiced in ancient Greece and the earliest reliable evidence for vegetarian theory and practice in Greece dates from the 6th century BCE. The Orphics, a religious movement spreading in Greece at that time, also practiced and promoted vegetarianism. Greek teacher Pythagoras, who promoted the altruistic doctrine of metempsychosis, may have practiced vegetarianism, but is also recorded as eating meat. A fictionalized portrayal of Pythagoras appears in Ovid's Metamorphoses, in which he advocates a form of strict vegetarianism. It was through this portrayal that Pythagoras was best known to English-speakers throughout the early modern period and, prior to the coinage of the word "vegetarianism", vegetarians were referred to in English as "Pythagoreans". Vegetarianism was also practiced about six centuries later in another instance (30 BCE–50 CE) in the northern Thracian region by the Moesi tribe (who inhabited present-day Serbia and Bulgaria), feeding themselves on honey, milk, and cheese.
Cold air damming typically happens in the mid-latitudes as this region lies within the Westerlies, an area where frontal intrusions are common. When the Arctic oscillation is negative and pressures are higher over the poles, the flow is more meridional, blowing from the direction of the pole towards the equator, which brings cold air into the mid-latitudes. Cold air damming is observed in the southern hemisphere to the east of the Andes, with cool incursions seen as far equatorward as the 10th parallel south. In the northern hemisphere, common situations occur along the east side of ranges within the Rocky Mountains system over the western portions of the Great Plains, as well as various other mountain ranges (such as the Cascades) along the west coast of the United States. The initial is caused by the poleward portion of a split upper level trough, with the damming preceding the arrival of the more equatorward portion. Some of the cold air damming events which occur east of the Rockies continue southward to the east of the Sierra Madre Oriental through the coastal plain of Mexico through the Isthmus of Tehuantepec. Further funneling of cool air occurs within the Isthmus, which can lead to winds of gale and hurricane-force, referred to as a Tehuantepecer. Other common instances of cold air damming take place on the coastal plain of east-central North America, between the Appalachian Mountains and Atlantic Ocean. In Europe, areas south of the Alps can be prone to cold air damming. In Asia, cold air damming has been documented near Taiwan and the Korean Peninsula.
== Mathematics and logic == Contraction (operator theory), in operator theory, state of a bounded operator between normed vector spaces after suitable scaling Contraction hierarchies, in applied mathematics, a technique to speed up shortest-path routing Contraction mapping, a type of function on a metric space Edge contraction or vertex contraction, graph operations used in graph theory Tensor contraction, an operation on one or more tensors that arises from the natural pairing of a finite-dimensional vector space and its dual Interior product, a tensor contraction specifically of a differential form with a vector field Left contraction and right contraction of multivectors in a geometric algebra, extensions of the inner product One of the rules of conditional independence, in probability Contraction (logic), a structural rule in proof theory
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.
Chromatographic methods can separate the two forms before detection. Enzymatic assays often measure total glutathione first and then use a separate procedure to estimate the oxidized fraction. The difference between total and oxidized amounts provides an indirect estimate of the reduced form.