The short version of thiol group fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-03-06. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
Accurate measurement of glutathione begins with careful sample handling. Because GSH oxidizes rapidly to GSSG, samples must be processed quickly or frozen immediately. Acid precipitation with metaphosphoric acid or perchloric acid is common; it lowers pH, precipitates proteins, and helps preserve the reduced form. Chelating agents such as EDTA can limit metal-catalyzed oxidation. For whole blood, hemolysis releases glutathione from erythrocytes, so plasma and serum values differ substantially from whole blood values.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | For reduced glutathione; the oxidized dimer has two sulfur atoms. |
| Molar mass | 307.32 g/mol | Calculated for the reduced form. |
| Appearance | White to off-white crystalline powder | Typical for solid reagent; solutions are usually colorless. |
| Solubility | Freely soluble in water | Poorly soluble in nonpolar organic solvents. |
| Typical storage | -20 °C, desiccated, protected from light | Limits oxidation, moisture uptake, and degradation. |
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 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 tripeptide composed of glutamate, cysteine, and glycine. The peptide bond between glutamate and cysteine uses the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group. This unusual linkage protects the molecule from many common peptidases. The cysteine side chain carries a thiol group that can undergo reversible oxidation. Because of this thiol, glutathione participates in redox reactions and helps maintain the reducing environment inside most cells in living systems.
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.
Internal aldimine formation: First, the ε-amino group of Lys258 forms a Schiff base linkage with the aldehyde carbon to generate an internal aldimine. Transaldimination: The internal aldimine then becomes an external aldimine when the ε-amino group of Lys258 is displaced by the amino group of aspartate. This transaldimination reaction occurs via a nucleophilic attack by the deprotonated amino group of Asp and proceeds through a tetrahedral intermediate. As this point, the carboxylate groups of Asp are stabilized by the guanidinium groups of the enzyme's Arg386 and Arg292 residues. Quinonoid formation: The hydrogen attached to the α-carbon of Asp is then abstracted (Lys258 is thought to be the proton acceptor) to form a quinonoid intermediate. Ketimine formation: The quinonoid is reprotonated, but now at the aldehyde carbon, to form the ketimine intermediate. Ketimine hydrolysis: Finally, the ketimine is hydrolyzed to form PMP and oxaloacetate. This mechanism is thought to have multiple partially rate-determining steps. However, it has been shown that the substrate binding step (transaldimination) drives the catalytic reaction forward.
In 1969, the Dubna team carried out chemical experiments on element 102 and concluded that it behaved as the heavier homologue of ytterbium. The Russian scientists proposed the name joliotium (Jo) for the new element after Irène Joliot-Curie, who had recently died, creating an element naming controversy that would not be resolved for several decades, with each group using its own proposed names. In 1992, the IUPAC-IUPAP Transfermium Working Group (TWG) reassessed the claims of discovery and concluded that only the Dubna work from 1966 correctly detected and assigned decays to nuclei with atomic number 102 at the time. The Dubna team are therefore officially recognized as the discoverers of nobelium, although it is possible that it was detected at Berkeley in 1959. This decision was criticized by Berkeley the following year, calling the reopening of the cases of elements 101 to 103 a "futile waste of time", while Dubna agreed with IUPAC's decision. In 1994, as part of an attempted resolution to the element naming controversy, IUPAC ratified names for elements 101–109. For element 102, it ratified the name nobelium (No) on the basis that it had become entrenched in the literature over the course of 30 years and that Alfred Nobel should be commemorated in this fashion. Because of outcry over the 1994 names, which mostly did not respect the choices of the discoverers, a comment period ensued, and in 1995 IUPAC named element 102 flerovium (Fl) as part of a new proposal, after either Georgy Flyorov or his eponymous Flerov Laboratory of Nuclear Reactions.
14 September NASA releases its first public study on UAP (also known as UFOs), and appoints Mark McInerney as the first Director of UAP, to scientifically and transparently study further such occurrences. A new record time for quantum coherence is reported, with a single-photon qubit encoded in a novel superconducting cavity for 34 milliseconds. A genetically engineered marine microorganism is shown to break down polyethylene terephthalate in salt water. This plastic, used in everything from water bottles to clothing, is a significant contributor to microplastic pollution in oceans. A study finds that rivers are warming and losing oxygen faster than oceans. Of nearly 800 rivers, warming occurred in 87% and oxygen loss occurred in 70%. The study projects that within 70 years, river systems could "induce acute death" and extinctions of aquatic species due to long low oxygen levels. Astronomers report studies related to the Hubble tension, a disagreement in results attempting to measure the Hubble constant, and find that the results from the James Webb Space Telescope support earlier results from the Hubble Space Telescope. According to astronomer Adam Riess, "With Webb confirming the measurements from Hubble, the Webb measurements provide the strongest evidence yet that systematic errors in Hubble's Cepheid photometry do not play a significant role in the present Hubble tension ...
Ghana produces and exports hydrocarbons such as sweet crude oil and natural gas. The 100%-state-owned filling station company, Ghana Oil Company, is the number one petroleum and gas filling station, and the 100%-state-owned state oil company Ghana National Petroleum Corporation oversees hydrocarbon exploration and production of petroleum and natural gas reserves. Ghana aims to further increase the output of oil to 2.2 million barrels (350,000 m3) per day and gas to 34,000,000 cubic metres (1.2×10^9 cu ft) per day. The Jubilee Oil Field, which contains up to 3 billion barrels (480,000,000 m3) of sweet crude oil, was discovered in 2007. Ghana is believed to have up to 5 billion barrels (790,000,000 m3) to 7 billion barrels (1.1×109 m3) of petroleum in reserves, which is the fifth-largest in Africa and the 21st-to-25th-largest proven reserves in the world. It also has up to 1.7×1011 cubic metres (6×10^12 cu ft) of natural gas in reserves. The government has drawn up plans to nationalise petroleum and natural gas reserves to increase government revenue. In 2015, Ghana produced 88 metric tonnes of gold as per the Our World in Data report. As of 2019, Ghana was the 7th largest producer of gold in the world, producing ~140 tonnes that year. This record saw Ghana surpass South Africa in output for the first time, making Ghana the largest gold producer in Africa. In addition to gold, Ghana exports silver, timber, diamonds, bauxite, and manganese, and has other mineral deposits. Ghana ranks 9th in the world in diamond export and reserve size.
== Standards == Standards for validation and verification of medical laboratories are outlined in the international standard ISO 15189, in addition to national and regional regulations. As per United States federal regulations, the following analytical tests need to be done by a medical laboratory that introduces a new testing device:
Sources: en.wikipedia.org
=== Ion mobility spectrometry === Explosive detection using ion mobility spectrometry (IMS) is based on velocities of ions in a uniform electric field. There are some variant to IMS such as Ion trap mobility spectrometry (ITMS) or Non-linear dependence on ion mobility (NLDM) which are based on IMS principle. The sensitivity of devices using this technology is limited to pg levels. The technology also requires the ionization of sample explosives which is accomplished by a radioactive source such as nickel-63 or americium-241. This technology is found in most commercially available explosive detectors such as the GE VaporTracer, Smith Sabre 4000 and Russian built MO-2M and MO-8. The presence of radioactive materials in these equipments cause regulatory hassles and requires special permissions at customs ports. These detectors cannot be field serviced and may pose radiation hazard to the operator if the casing of the detector cracks due to mishandling. Bi-yearly checks are mandatory on such equipment in most countries by regulating agencies to ensure that there are no radiation leaks. Disposal of these equipments is also controlled owing to the high half-life of the radioactive material used. Electrospray ionization, mobility analysis (DMA) and tandem mass spectrometry (MS/MS) is used by SEDET (Sociedad Europea de Detección) for the “Air Cargo Explosive Screener (ACES)”, targeted to aviation cargo containers currently under development in Spain.
On some early frost-free models, the defrost limiter also sends a signal to the defrost timer to start the compressor and fan as soon as it shuts off the heating element before the timed defrost cycle ends. When the defrost cycle is completed, the compressor and fan are allowed to cycle back on. Frost-free refrigerators, including some early frost-free refrigerators/freezers that used a cold plate in their refrigerator section instead of airflow from the freezer section, generally don't shut off their refrigerator fans during defrosting. This allows consumers to leave food in the main refrigerator compartment uncovered, and also helps keep vegetables moist. This method also helps reduce energy consumption, because the refrigerator is above freeze point and can pass the warmer-than-freezing air through the evaporator or cold plate to aid the defrosting cycle.
On 5 December 2001, a 2,000lb GPS-guided bomb landed among the Green Berets from ODA 574, killing 3 members and wounding the rest of the team, over 20 of Karzai's militia were also killed and Karzai himself slightly wounded. ODB 570 and ODA 524 were immediately dispatched by helicopter to assist with the wounded and to eventually replace the fallen operators of ODA 574. ODA 572 and a CIA Jawbreaker team (small group of CIA SAD ground branch operators) were dispatched to eastern Afghanistan where they recruited some 2,500 to 3,000 into the Afghan Militia Force to take part in the Battle of Tora Bora. On December 20, following the battle, ODA 561 were inserted into the White Mountains to support ODA 572 in conducting sensitive site exploitation of the caves and to assist with recovering DNA samples from terrorist bodies. Time reported that on 4 January 2002, Green Beret SFC Scott Neil jumped out the back of an MH-53 half a mile from a suspected al-Qaeda compound, 140 miles south of Kabul. With just one-hour on-scene time due to limited helicopter fuel, Neil rushed through AK-47 fire and overcame the al-Qaeda fighters; intelligence from the compound proved it to be an al-Qaeda way station, containing hundreds of fake passports to give terrorists new identities, and multiple computers, powered by car batteries and linked to satellite phones for internet connection.
== Physiological functions == Through their production of interleukin-22 (IL-22), Th22 cells have been shown to be protective against a number of bacterial and viral pathogens. Interleukin-22 (IL-22) regulates different innate immune mechanisms to eliminate infiltration of invasive pathogens into the skin, gut and respiratory tract. Interleukin-22 (IL-22) influences keratinocytes and epithelial cells to stimulate proliferation and differentiation, thus promoting wound healing and cohesion of barrier integrity. Interleukin-22 (IL-22) also enhances stromal secretion of antimicrobial peptides, as well as production of the chemokines which promote recruitment of other immune cells.
Sources: en.wikipedia.org
== Adverse effects == Lercanidipine is generally well tolerated; no single adverse effect has been observed in more than 1% of patients treated with this drug. Typical side effects are similar to those of other drugs of this class and include headache, dizziness, tachycardia (fast heartbeat), palpitations, flush, and oedema. Hypersensitivity reactions occur in less than one patient in 10,000. Oedemas are significantly less common under lercanidipine when compared to first-generation dihydropyridines such as nifedipine. For other side effects, data are inconclusive: A study comparing lercanidipine to first-generation drugs found no difference in the frequency of headache and flush, but switching from amlodipine, felodipine or nitrendipine (all at least second generation) to lercanidipine significantly decreased side effects in another study.
The estimated prevalence is 16% in people from Cyprus, 1% in Thailand, and 3–8% in populations from Bangladesh, China, India, Malaysia and Pakistan. Estimates suggest that approximately 1.5% of the global population (80 – 90 million people) are β-thalassemia carriers. However, exact data on carrier rates in many populations are lacking, particularly in developing areas of the world known or expected to be heavily affected. Because of the prevalence of the disease in countries with little knowledge of thalassemia, access to proper treatment and diagnosis can be difficult. While there are some diagnostic and treatment facilities in developing countries, in most cases these are not provided by government services and are available only to patients who can afford them. In general, poorer populations only have access to limited diagnostic facilities and blood transfusions. In some developing countries, there are virtually no facilities for diagnosis or management of thalassemia.
=== Multiwell plate === Multiwell plates are multiple petri dishes incorporated into one container, with the number of individual wells ranging from 6 to over 1536. Multiwell Plate Assays are convenient for handling necessary dosages and replicates. There are a wide range of plate types that have a standardized footprint, supporting equipment, and measurement systems. Electrodes can be integrated into the bottom of the plates to capture information as a result of the binding assays. The binding reagents become immobilized on the electrode surface and then can be analyzed. The multiwell plates are manufactured to allow researchers to create and manipulate different types of assays (i.e., bioassays, immunoassays, etc.) within each multiwell plate. Due to the variability in multiwell plate formatting, it is not uncommon for artifacts to arise. Artifacts are due to the different environments found within the different wells on the plate, especially near the edges and center of the wells. Such effects are known as well effects, edge effects, and plate effects. Thus, emphasizing the necessity to position assay designs in the correct manner both within, and between, each plate. The use of multiwell plates are common when measuring in vitro biological assay activity, or measuring immunoreactivity through immunoassays. Artifacts can be avoided by maintaining plate uniformity by applying the same dose of the specific medium in each well, in addition to maintaining atmospheric pressure and temperature rates in order to reduce humidity.
Anabolism ( ə-NAB-ə-liz-əm) is the set of metabolic pathways that construct macromolecules like DNA or RNA from smaller units. These reactions require energy, known also as an endergonic process. Anabolism is the building-up aspect of metabolism, whereas catabolism is the breaking-down aspect. Metabolism is rathersynonymous with biosynthesis.
== Principle == Capillary electrochromatography (CEC) combines the principles used in HPLC and CE. The mobile phase is driven across the chromatographic bed using electroosmosis instead of pressure (as in HPLC). Electroosmosis is the motion of liquid induced by an applied potential across a porous material, capillary tube, membrane or any other fluid conduit. Electroosmotic flow is caused by the Coulomb force induced by an electric field on net mobile electric charge in a solution. Under alkaline conditions, the surface silanol groups of the fused silica will become ionised leading to a negatively charged surface. This surface will have a layer of positively charged ions in close proximity which are relatively immobilised. This layer of ions is called the Stern layer. The thickness of the double layer is given by the formula:
Sources: en.wikipedia.org
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.
It is synthesized in the body from amino acids, so it is not classified as an essential dietary nutrient for most people. Dietary and supplemental forms are studied for their effects on tissue levels and health markers. Evidence varies by population and outcome.
The phrase highlights its high intracellular concentration and its role in several antioxidant and detoxification reactions. It is not the only antioxidant, and the term can oversimplify its functions. Scientific descriptions usually specify the pathway or enzyme involved.
Glutathione oxidizes quickly when cells are disrupted or when samples sit at room temperature. Rapid processing or immediate freezing minimizes the conversion of GSH to GSSG. This step helps ensure that the measured ratio reflects the original biological state.