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 2026-03-24 and is reviewed periodically as new material appears.
Laboratory measurement of glutathione typically starts with rapid acid extraction to prevent oxidation and enzymatic degradation. Common methods include enzymatic recycling assays, high-performance liquid chromatography, and liquid chromatography coupled with mass spectrometry. The recycling assay uses glutathione reductase and a thiol-reactive colorimetric or fluorescent reagent, measuring total glutathione after converting disulfide forms. Chromatographic methods can separate reduced and oxidized forms, which helps when the redox ratio is the target. Choice of method affects sensitivity, specificity, and the amount of sample needed.
Samples for glutathione analysis require careful handling because the compound oxidizes readily and can be consumed by enzymes after collection. Blood is often treated with acid or thiol-blocking agents soon after draw, and plasma should be separated quickly from red blood cells. Tissues are usually snap-frozen or extracted immediately. Aqueous solutions of glutathione are less stable than dry powder and degrade faster at neutral or alkaline pH, in light, or with dissolved oxygen. Repeated freeze-thaw cycles also reduce reliability.
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 |
|---|---|---|
| Recommended storage | −20 °C, desiccated | For dry powder; limit light and air exposure |
| Solution stability | Hours to days at neutral pH | Faster loss at warm, alkaline, or oxygen-rich conditions |
| Routine measurement | LC-MS/MS or HPLC | Enzymatic recycling assays measure total glutathione |
| Thiol pKa | About 8.7 | The thiolate form reacts with oxidants and electrophiles |
| Common abbreviations | GSH and GSSG | GSSG is the disulfide-linked dimer |
Measuring glutathione requires attention to oxidation during sample handling, because GSH in biological samples can convert to GSSG or form mixed disulfides with proteins after collection. Acidic extraction, rapid cooling, and chelating agents are commonly used to limit such changes. Analytical methods usually distinguish free reduced glutathione, total glutathione, and protein-bound forms. Because these forms have different stability and reactivity, reported values depend heavily on the preparation protocol. No single preparation is universally suitable for every biological matrix or analytical goal.
Several techniques are used for quantification. Enzymatic recycling assays rely on glutathione reductase and a colorimetric or fluorescent readout, offering sensitivity for total glutathione. High-performance liquid chromatography can separate GSH from GSSG and other thiols, often with UV, fluorescence, or electrochemical detection. Mass spectrometry provides structural confirmation and can quantify low-abundance species when paired with separation. Each approach has trade-offs in specificity, throughput, and equipment requirements, so method selection depends on the research question and available instrumentation.
Stability depends on pH, temperature, oxygen exposure, and trace metals. Aqueous solutions of reduced glutathione are susceptible to oxidation, especially when neutral or alkaline and exposed to air. Transition metal ions can catalyze thiol oxidation, so chelators and inert atmospheres are sometimes used in research settings. Standards are typically stored cold and desiccated, with limited freeze-thaw cycles. Questions remain about how closely in vitro stability data reflect the behavior of glutathione within intact cells and tissues.
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.
Glutathione participates in detoxification reactions, amino acid transport, and the maintenance of protein thiols. It serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. In research literature, altered glutathione status appears in studies of aging, infection, metabolic stress, and environmental exposure. Whether low glutathione is a cause, consequence, or marker of such conditions often remains unresolved. Direct measurement in blood or tissue provides a snapshot, but results depend on sample handling, timing, and the method used.
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.
=== 20th century === Elly Agallidis (1914–2006), Greek physical chemist Nancy Allbritton, American analytical and biochemist Marianne Angermann (1904-1977), German-Spanish-New Zealand biochemist Valerie Ashby, American chemist Barbara Askins (born 1939), American chemist Kim K. Baldridge, American computational chemist Alice Ball (1892–1916), American chemist Carolyn Bertozzi (born 1966), American biochemist Cynthia Burrows, American physical organic chemist Asima Chatterjee (1917–2006), Indian organic chemist Ecaterina Ciorănescu-Nenițescu (1909–2000), Romanian chemist Astrid Cleve (1875–1968), Swedish chemist Mildred Cohn (1913–2009), American chemist Janine Cossy (born 1950), French organic chemist Maria Skłodowska-Curie (1867–1934), Polish-French physicist and chemist (discoverer of polonium and radium, pioneer in radiology); Nobel laureate in physics 1903, and in chemistry 1911 Jillian Lee Dempsey (born 1983), American chemist Vy M. Dong, American organic chemist Abigail Doyle (born 1980), American organic chemist Odile Eisenstein (born 1949), French, theoretical chemist Gertrude B. Elion (1918–1999), American biochemist (Nobel prize in Physiology or Medicine 1988 for drug development) Margaret Faul, Irish/American organic chemist Mary Peters Fieser (1909–1997), American organic chemist Marye Anne Fox (1947–2021), American physical organic chemist Rosalind Franklin (1920–1957), British physical chemist and crystallographer Helen Murray Free (1923–2021), American chemist Gunda I.
The regulation of cell adhesion The regulation of glycoprotein synthesis The regulation of blood protein levels The binding of soluble extracellular and intercellular glycoproteins As a receptor on the surface of mammalian liver cells for the recognition of galactose residues, which results in removal of certain glycoproteins from the circulatory system As a receptor that recognizes hydrolytic enzymes containing mannose-6-phosphate, and targets these proteins for delivery to the lysosomes; I-cell disease is one type of defect in this particular system. Lectins are known to play important roles in the innate immune system. C-type lectins such as the mannose-binding lectin, help mediate the first-line defense against invading microorganisms. Other immune lectins play a role in self-nonself discrimination and they likely modulate inflammatory and autoreactive processes. Intelectins (X-type lectins) bind microbial glycans and may function in the innate immune system as well. Lectins may be involved in pattern recognition and pathogen elimination in the innate immunity of vertebrates including fishes.
== Diagnosis == Diagnostic criteria for Type 5 diabetes are under development. In the spring of 2025, the International Diabetes Federation (IDF) tasked a working group, which includes Meredith Hawkins, a professor of medicine at Albert Einstein College of Medicine in The Bronx, New York, with developing official diagnostic and therapeutic guidelines for Type 5 diabetes.
=== Democratic primary === Caitlin Rourk, Democratic Nominee for the 10th Congressional District, grew up near Washington, D.C., as the daughter of two public school teachers. She served as an intelligence officer in the Texas Army National Guard and U.S. Army Reserve, participating in full-time missions supporting disaster response, border operations, and public health programs. Early in her career, Rourk engaged in bipartisan public policy work focused on deficit reduction and energy security, later leading corporate communications at Dell Technologies. A resident of Central Texas for over a decade, she lives in the Eanes Independent School District, where her children attend public school. Rourk is the Democratic nominee running to represent Texas's 10th Congressional District in the 2026 election, winning her primary with more than 60% of the vote for an open seat created by the retirement of long-serving Republican Representative Michael McCaul. The newly drawn district encompasses 13 counties, stretching from the Houston suburbs through rural East Texas to northern Austin. Positioning herself as a pragmatic problem solver and servant leader, Rourk has centered her campaign on grassroots door-knocking, deep organizing, and restoring accountability through proposals such as mandating regular open town halls in every congressional district.
Sources: en.wikipedia.org
In the United Kingdom, a new excise duty on vaping products (Vaping Products Duty) is scheduled to take effect from 1 October 2026, with registrations opening on 1 April 2026, following consultation. The government said it would implement a flat-rate structure of £2.20 per 10 mL of vaping liquid, alongside a one-off increase in tobacco duty to preserve the financial incentive to switch from smoking to vaping.
In the mitochondrion, pyruvate is oxidized by the pyruvate dehydrogenase complex to the acetyl group, which is fully oxidized to carbon dioxide by the citric acid cycle. Every "turn" of the citric acid cycle produces two molecules of carbon dioxide, one equivalent of ATP guanosine triphosphate (GTP) through substrate-level phosphorylation catalyzed by succinyl-CoA synthetase, as succinyl-CoA is converted to succinate, three equivalents of NADH, and one equivalent of FADH2. NADH and FADH2 are recycled (to NAD+ and FAD, respectively) by oxidative phosphorylation, generating additional ATP. The oxidation of NADH results in the synthesis of 2–3 equivalents of ATP, and the oxidation of one FADH2 yields between 1–2 equivalents of ATP. The majority of cellular ATP is generated by this process. Although the citric acid cycle itself does not involve molecular oxygen, it is an obligately aerobic process because O2 is used to recycle the NADH and FADH2. In the absence of oxygen, the citric acid cycle ceases. The generation of ATP by the mitochondrion from cytosolic NADH relies on the malate-aspartate shuttle (and to a lesser extent, the glycerol-phosphate shuttle) because the inner mitochondrial membrane is impermeable to NADH and NAD+. Instead of transferring the generated NADH, a malate dehydrogenase enzyme converts oxaloacetate to malate, which is translocated to the mitochondrial matrix. Another malate dehydrogenase-catalyzed reaction occurs in the opposite direction, producing oxaloacetate and NADH from the newly transported malate and the mitochondrion's interior store of NAD+.
It seemed to me quite certain that if I did not take a hand in the game the forces on the spot would soon make short work of President Kruger. Then I should be face to face with an American Republic—American in the sense of being intensely hostile to and jealous of Britain—an American Republic largely manned by Americans and Sydney Bulletin Australians who cared nothing for the [Union Jack]. They would have all the Rand at their disposal. The drawing power of the Outlander Republic would have collected round it all the other Colonies. They would have federated with it as a centre, and we should have lost South Africa. To avert this catastrophe, to rope in the Outlanders before it was too late, I did what I did. In mid-1895, Rhodes planned a raid by an armed column from Rhodesia, the British colony to the north, to support an uprising of Uitlanders with the goal of taking control. The raid soon ran into difficulties, beginning with hesitation by the Uitlander leaders.
Sources: en.wikipedia.org
Chemokines (from Ancient Greek χῠμείᾱ (khumeíā) 'alchemy' and κῑ́νησῐς (kī́nēsis) 'movement'), or chemotactic cytokines, are a family of small cytokines or signaling proteins secreted by cells that induce directional movement of leukocytes, as well as other cell types, including endothelial and epithelial cells. In addition to playing a major role in the activation of host immune responses, chemokines are important for biological processes, including morphogenesis and wound healing, as well as in the pathogenesis of diseases like cancers. Cytokine proteins are classified as chemokines according to behavior and structural characteristics. In addition to being known for mediating chemotaxis, chemokines are all approximately 8–10 kilodaltons in mass and have four cysteine residues in conserved locations that are key to forming their 3-dimensional shape. These proteins have historically been known under several other names including the SIS family of cytokines, SIG family of cytokines, SCY family of cytokines, Platelet factor-4 superfamily or intercrines. Some chemokines are considered pro-inflammatory and can be induced during an immune response to recruit cells of the immune system to a site of infection, while others are considered homeostatic and are involved in controlling the migration of cells during normal processes of tissue maintenance or development. Chemokines are found in all vertebrates, some viruses and some bacteria, but none have been found in other invertebrates. Chemokines have been classified into four main subfamilies: CXC, CC, CX3C and C.
Early experiments resembling activity-based profiling were conducted in the 1970s, when small molecules were used to study the mechanism of action of the serine-modifying antibiotic penicillin. The modern era of ABPP began in the 1990s with the development of ABPs compatible with proteomic workflows, and the first applications of ABPP were reported during this decade in studies of proteases. In 1999, the Cravatt lab formally introduced the term "activity-based protein profiling," establishing a framework for systematic functional proteomics. Subsequent work by Ben Cravatt at The Scripps Research Institute, Matthew Bogyo at Stanford University, and Herman S. Overkleeft at Leiden University helped define the field through the design of probes targeting serine hydrolases, cysteine proteases, oxidoreductases, human cytochrome P450s and other enzyme families. Since its inception, ABPP has expanded rapidly, with bibliometric analyses documenting exponential growth in publications and widespread adoption across North America, Europe, and Asia. Advances in mass spectrometry and protein separation technologies further accelerated the integration of ABPP into proteomic research, enabling the characterization of enzyme activity on a global scale and establishing ABPP as a cornerstone of functional proteomics.
Early work on the study of the chemistry of rutherfordium focused on gas thermochromatography and measurement of relative deposition temperature adsorption curves. The initial work was carried out at Dubna in an attempt to reaffirm their discovery of the element. Recent work is more reliable regarding the identification of the parent rutherfordium radioisotopes. The isotope 261mRf has been used for these studies, though the long-lived 267Rf (produced in the decay chain of 291Lv, 287Fl, and 283Cn) may be advantageous for future experiments. The experiments relied on the expectation that rutherfordium would be a 6d element in group 4 and should therefore form a volatile molecular tetrachloride, that would be tetrahedral in shape. Rutherfordium(IV) chloride is more volatile than its lighter homologue hafnium(IV) chloride (HfCl4) because its bonds are more covalent. A series of experiments confirmed that rutherfordium behaves as a typical member of group 4, forming a tetravalent chloride (RfCl4) and bromide (RfBr4) as well as an oxychloride (RfOCl2). A decreased volatility was observed for RfCl4 when potassium chloride is provided as the solid phase instead of gas, highly indicative of the formation of nonvolatile K2RfCl6 mixed salt.
== External links == H. E. Carter & Minor J. Coon: William Cumming Rose from National Academy of Sciences Daphne A. Roe (1981) William Cumming Rose: A biographical sketch Journal of Nutrition 111(8):1311–20. Noyes Laboratory at the University of Illinois, Urbana-Champaign from American Chemical Society National Historic Chemical Landmarks William C. Rose Papers, University of Illinois Archives https://loguepedia.com/william-rose-american-scientist/
Sources: en.wikipedia.org
Common approaches include enzymatic recycling assays, HPLC, and LC-MS/MS. Acid extraction and rapid processing limit oxidation before analysis.
Reduced glutathione oxidizes easily and can change after collection. Delays, warmth, light, and repeated freezing can alter measured values.
Labels may state total glutathione without specifying reduced and oxidized content. Purity, counterions, and actual assay can vary between products.
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.