Everything below concerns redox status. We keep the language plain, cite what the science says, and separate well-supported claims from open questions.
Last reviewed on 2026-03-04. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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.
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.
| 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 |
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 tripeptide composed of glutamate, cysteine, and glycine, and it is the most abundant non-protein thiol in most living cells. The reduced form, GSH, carries a sulfhydryl group that can donate electrons, while the oxidized form, GSSG, forms when two GSH molecules link via a disulfide bond. The balance between these two forms helps define the cellular redox environment, and their ratio is often used as an indicator of oxidative stress. Because the sulfhydryl group is reactive, glutathione participates in many cellular processes, including detoxification and protein regulation.
Glutathione is synthesized in two ATP-dependent steps. First, gamma-glutamylcysteine synthetase links glutamate and cysteine; second, glutathione synthetase adds glycine to form the complete tripeptide. The pathway is feedback-inhibited by GSH itself, which helps maintain steady intracellular levels. Tissues vary widely in glutathione content, with the liver typically containing the highest concentrations, followed by the kidneys, lungs, and erythrocytes. Because cysteine is often limiting, its availability influences synthesis rates, and regulation of this pathway varies by cell type.
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 1907, American tea merchant Thomas Sullivan began distributing samples of his tea in small bags of silk with a drawstring. Consumers noticed they could simply leave the tea in the bag and reuse it with fresh tea. However, the potential of this distribution and packaging method would not be fully realised until later. During World War II, tea was rationed in the United Kingdom. In 1953, after rationing in the UK ended, Yorkshire-based tea manufacturer Tetley launched the tea bag in the UK, and it was an immediate success. The "pyramid tea bag" (or sachet), introduced by Lipton and PG Tips/Scottish Blend in 1996, attempts to address one of the connoisseurs' arguments against paper tea bags by way of its three-dimensional tetrahedron shape, which allows more room for tea leaves to expand while steeping. However, some types of pyramid tea bags have been criticised as being environmentally unfriendly, since their synthetic material is not as biodegradable as loose tea leaves and paper tea bags.
== Safety == Lime sulfur reacts with strong acids (including stomach acid) to produce highly toxic hydrogen sulfide (rotten egg gas) and usually has a distinct "rotten egg" odor. Lime sulfur is not flammable, but it can release highly irritating sulfur dioxide gas in a fire. Safety goggles and impervious gloves should be worn when handling lime sulfur. Lime sulfur solutions are strongly alkaline (typical commercial concentrates have a pH over 11.5 because of the presence of dissolved sulfides and hydroxide anions) and are harmful to living organisms and can cause blindness if splashed in the eyes. The corrosive nature of lime sulfur is due to the reduced sulfur species it contains, in particular sulfides responsible for stress corrosion cracking and the thiosulfates that cause pitting corrosion. Localized corrosion by the reduced sulfur species can be significant; even the mere presence of elemental sulfur in contact with metals is enough to corrode them considerably, including so-called stainless steels.
=== Therapeutic opportunities === The ribosome is a prominent drug target for antibacterials, which interfere with translation at different stages of the elongation cycle Most clinically relevant translation compounds are inhibitors of bacterial translation, but inhibitors of eukaryotic translation may also hold therapeutic potential for application in cancer or antifungal chemotherapy. Elongation inhibitors show antitumor activity 'in vivo' and 'in vitro'. One toxic inhibitor of eukaryotic translation elongation is the glutarimide antibiotic cycloheximide (CHX), which has been co-crystallized with the eukaryotic 60S subunit and binds in the ribosomal E site. The structural characterization of the eukaryotic ribosome may enable the use of structure-based methods for the design of novel antibacterials, wherein differences between the eukaryotic and bacterial ribosomes can be exploited to improve the selectivity of drugs and therefore reduce adverse effects.
=== Third term (2022–2023) === After his district was made significantly more Republican during the 2020 redistricting process, Talarico announced he would run in neighboring House District 50, a safe Democratic seat being vacated by Celia Israel. His previous district was a swing district. Talarico won the primary election with 78.5% of the vote and the general election with 76.8%. During the 88th Texas Legislature, he was the primary author of House Bill 25, which would create the Texas Wholesale Prescription Drug Importation Program and allow Texas to import lower-cost Canadian medications approved by the U.S. Food and Drug Administration. Talarico was an outspoken critic of legislation that would have required the display of the Ten Commandments in all elementary and secondary classrooms, on the constitutional grounds of separation of church and state. He called the measure "un-American" and "un-Christian". The bill was not signed into law.
== Use in food == Cyanocobalamin is added as an ingredient to fortify nutrition in products such as baby formula, breakfast cereals and energy drinks as well as livestock feed. Endogenous vitamin B12 becomes inactive when exposed to hydrogen cyanide and nitric oxide in cigarette smoke. Vitamin B12 deficiency can develop with heavy regular use of nitrous oxide N2O, also known as "laughing gas", used for anaesthesia in a clinical setting or as a propellant gas, commonly abused as a recreational drug.
Sources: en.wikipedia.org
== Literature == Carl-Gerd Dieris: Zur Frage der Luminiszenz von thermooxidativ geschädigten Polycarpolaktam. Eine neue Synthese des Bakterienfarbstoffes Indigoidin und seiner Tetra-N-alkylderivate. 1980. Hans Günter Schlegel: Allgemeine Mikrobiologie. Thieme Verlagsgruppe, Stuttgart 1992, ISBN 978-3-13-444607-4. Reverchon, Sylvie; Rouanet, Carine; Expert, Dominique; Nasser, William (2002-01-02). "Characterization of Indigoidine Biosynthetic Genes in Erwinia chrysanthemi and Role of This Blue Pigment in Pathogenicity". Journal of Bacteriology. 184 (3): 654–665. doi:10.1128/JB.184.3.654-665.2002. PMC 139515. PMID 11790734. Christin Schönfeld: Charakterisierung und biochemische Analyse der Indigoidin Synthease BpsA aus S. lavendulae ATCC 11924. Masterarbeit, Philipps-Universität Marburg 2012. M. Müller, S. Ausländer, D. Ausländer, C. Kemmer, M. Fussenegger: A novel reporter system for bacterial and mammalian cells based on the non-ribosomal peptide indigoidine. Metabolic Engineering 14/2012, S. 325–335 (doi:10.1016/j.ymben.2012.04.002). H. Kobayashi, Y. Nogi, K. Hirokoshi: New violet 3,3'-bipyridyl pigment purified from deep-sea microorganism Shewanella violacea DSS12. In: Extremophiles Nr. 11(2)/2012, S. 245–250. PMID 17102923.
In August 2010, James Brokenshire, the Home Office drugs minister, announced plans to create a new category in the Misuse of Drugs Act, through the Police Reform and Social Responsibility Bill, that would allow new legal highs to be made temporarily illegal, without the need for a vote in parliament or advice from the ACMD, as was required to categorise mephedrone. According to the Independent Scientific Committee on Drugs, after mephedrone was made illegal, a street trade in the drug emerged, with prices around double those prior to the ban, at £20–£25 per gram. In September 2010, Druglink reported the ban had a mixed effect on mephedrone use, with it decreasing in some areas, remaining similar in others, and becoming more prevalent in some areas. In an online survey of 150 users after the ban, 63% said they were continuing to use mephedrone; of those, half claimed unchanged usage amounts (as to dosage and frequency), and half claimed decreased usage. Compared to previous surveys, more users purchased it from dealers, rather than the internet. The average price per gram was £16, compared to around £10 before the ban. The 2010 Mixmag survey of 2,500 nightclubbers found one quarter had used mephedrone in the previous month, the price had roughly doubled since it was made illegal, and it was more likely to be cut with other substances. Of those who had already used mephedrone prior to the ban, 75% had continued to use it after the ban. Of the various drugs used by the survey participants, users were more likely to have concerns about it.
Absolute bioavailability compares the bioavailability of the active drug in systemic circulation following non-intravenous administration (i.e., after oral, buccal, ocular, nasal, rectal, transdermal, subcutaneous, or sublingual administration), with the bioavailability of the same drug following intravenous administration. It is the fraction of exposure to a drug (AUC) through non-intravenous administration compared with the corresponding intravenous administration of the same drug. The comparison must be dose normalized (e.g., account for different doses or varying weights of the subjects); consequently, the amount absorbed is corrected by dividing the corresponding dose administered. In pharmacology, in order to determine absolute bioavailability of a drug, a pharmacokinetic study must be done to obtain a plasma drug concentration vs time plot for the drug after both intravenous (iv) and extravascular (non-intravenous, i.e., oral) administration. The absolute bioavailability is the dose-corrected area under curve (AUC) non-intravenous divided by AUC intravenous. The formula for calculating the absolute bioavailability, F, of a drug administered orally (po) is given below (where D is dose administered).
where N0 is the number of atoms of the isotope in the original sample (at time t = 0, when the organism from which the sample was taken died), and N is the number of atoms left after time t. λ is a constant that depends on the particular isotope; for a given isotope it is equal to the reciprocal of the mean-life – i.e. the average or expected time a given atom will survive before undergoing radioactive decay. The mean-life, denoted by τ, of 14C is 8,267 years, so the equation above can be rewritten as:
Sources: en.wikipedia.org
A dietary supplement is a manufactured product intended to supplement a person's diet in the form of a pill, capsule, tablet, powder, or liquid. A supplement can provide nutrients that are either extracted from food sources or are synthesized (to increase the quantity of their consumption). The classes of nutrient compounds in supplements include vitamins, minerals, fiber, fatty acids, and amino acids. Dietary supplements may also contain substances that have not been confirmed as being essential to life, such as plant pigments or polyphenols, and so, by definition, are not necessarily nutrients. However, they may still be marketed as having a beneficial biological effect. Animals can also be a source of supplement ingredients; for example, collagen may be extracted from chickens or fish. Supplements are sold in multiple doses, ranging from one time usage to entire courses. They may also be enhanced with nutrient ingredients. In the United States, the supplement industry was estimated to have a value of $151.9 billion in 2021. There are more than 95,000 dietary supplement products marketed in the United States, and about 60% of the American adult population consumes dietary supplements, 74% among Americans over the age of 60. Multivitamins are the most commonly used product among types of dietary supplements. The United States National Institutes of Health (NIH) states that some supplements may help provide essential nutrients or support overall health and performance for those with limited dietary variety.
Potash is primarily a mixture of potassium salts because plants have little or no sodium content, and the rest of a plant's major mineral content consists of calcium salts of relatively low solubility in water. While potash has been used since ancient times, its composition was not understood. Georg Ernst Stahl obtained experimental evidence that led him to suggest the fundamental difference of sodium and potassium salts in 1702, and Henri Louis Duhamel du Monceau was able to prove this difference in 1736. The exact chemical composition of potassium and sodium compounds, and the status as chemical element of potassium and sodium, was not known then, and thus Antoine Lavoisier did not include the alkali in his list of chemical elements in 1789. For a long time the only significant applications for potash were the production of glass, bleach, soap and gunpowder as potassium nitrate. Potassium soaps from animal fats and vegetable oils were especially prized because they tend to be more water-soluble and of softer texture, and are therefore known as soft soaps. The discovery by Justus Liebig in 1840 that potassium is a necessary element for plants and that most types of soil lack potassium caused a steep rise in demand for potassium salts. Wood-ash from fir trees was initially used as a potassium salt source for fertilizer, but, with the discovery in 1868 of mineral deposits containing potassium chloride near Staßfurt, Germany, the production of potassium-containing fertilizers began at an industrial scale.
=== DNA concentration === The concentration of DNA can affect the rate of ligation, and whether the ligation is an inter-molecular or intra-molecular reaction. Ligation involves joining up the ends of a DNA with other ends, however, each DNA fragment has two ends, and if the ends are compatible, a DNA molecule can circularize by joining its own ends. At high DNA concentration, there is a greater chance of one end of a DNA molecule meeting the end of another DNA, thereby forming intermolecular ligation. At a lower DNA concentration, the chance that one end of a DNA molecule would meet the other end of the same molecule increases, therefore intramolecular reaction that circularizes the DNA is more likely. The transformation efficiency of linear DNA is also much lower than circular DNA, and for the DNA to circularize, the DNA concentration should not be too high. As a general rule, the total DNA concentration should be less than 10 μg/ml. The relative concentration of the DNA fragments, their length, as well as buffer conditions are also factors that can affect whether intermolecular or intramolecular reactions are favored. The concentration of DNA can be artificially increased by adding condensing agents such as cobalt hexamine and biogenic polyamines such as spermidine, or by using crowding agents such as polyethylene glycol (PEG) which also increase the effective concentration of enzymes.
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.
Common methods include enzymatic recycling assays, liquid chromatography, and mass spectrometry. Many protocols separate reduced glutathione from its oxidized disulfide form before detection.