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 2026-04-27 and is reviewed periodically as new material appears.
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.
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.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Solid storage temperature | -20 °C | Desiccated, protected from light |
| Solution stability | Hours to days at neutral pH | Acidic pH and low oxygen slow oxidation |
| Oxidized form | Glutathione disulfide (GSSG) | Formed by thiol oxidation |
| Typical analytical method | LC-MS/MS or enzymatic recycling | Choice depends on matrix and specificity |
| Thiol pKa | Approximately 9.2 | Influences reactivity at physiological pH |
Commercial glutathione is available in research-grade, food-grade, and supplement-grade forms, and purity specifications differ accordingly. Certificates of analysis commonly report identity by nuclear magnetic resonance or mass spectrometry, purity by HPLC, residual solvents, and heavy metals. Reference standards with assigned purity support calibration, while isotopically labeled glutathione can serve as an internal standard for mass spectrometry. For supplements, label claims may not be independently verified, and regulatory oversight varies by country. Verification often involves third-party testing for identity, potency, and contaminants.
Quantifying glutathione requires distinguishing GSH from GSSG and preventing oxidation during sample preparation. Common approaches include the enzymatic recycling assay, often called the Tietze method, which measures total glutathione after converting GSSG to GSH. HPLC with ultraviolet or fluorescence detection and LC-MS/MS can separate and quantify both forms, sometimes after derivatization of the thiol group. Blood, plasma, and tissue samples differ in matrix and baseline concentrations, so method validation must account for recovery, linearity, and interference. No single assay is universally standard.
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 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.
=== PD-L1 === Atezolizumab (Tecentriq) is a fully humanised IgG1 (immunoglobulin 1) antibody developed by Roche Genentech. In 2016, the FDA approved atezolizumab for urothelial carcinoma and non-small cell lung cancer. Avelumab (Bavencio) is a fully human IgG1 antibody developed by Merck Serono and Pfizer. Avelumab is FDA approved for the treatment of metastatic merkel-cell carcinoma. It failed phase III clinical trials for gastric cancer. Durvalumab (Imfinzi) is a fully human IgG1 antibody developed by AstraZeneca. Durvalumab is FDA approved for the treatment of urothelial carcinoma and unresectable non-small cell lung cancer after chemoradiation. Cosibelimab (Unloxcyt) by Checkpoint Therapeutics is a PD-L1 inhibitor developed by Dana Farber, and was approved in the United States in December 2024 for cutaneous squamous cell carcinoma.
== Function == Kisspeptin is involved in the regulation of endocrine function and the onset of puberty, with activation of the kisspeptin receptor triggering release of gonadotropin-releasing hormone (GnRH), and release of kisspeptin itself being inhibited by oestradiol but enhanced by GnRH. Reductions in kisspeptin levels with age may conversely be one of the reasons behind age-related declines in levels of other endocrine hormones such as luteinizing hormone.
As the real world had shown the importance of sulfate aerosol concentrations to the global climate, research into the subject accelerated. Formation of the aerosols and their effects on the atmosphere can be studied in the lab, with methods like ion-chromatography and mass spectrometry Samples of actual particles can be recovered from the stratosphere using balloons or aircraft, and remote satellites were also used for observation. This data is fed into the climate models, as the necessity of accounting for aerosol cooling to truly understand the rate and evolution of warming had long been apparent, with the IPCC Second Assessment Report being the first to include an estimate of their impact on climate, and every major model able to simulate them by the time IPCC Fourth Assessment Report was published in 2007. Many scientists also see the other side of this research, which is learning how to cause the same effect artificially. While discussed around the 1990s, if not earlier, stratospheric aerosol injection as a solar geoengineering method is best associated with Paul Crutzen's detailed 2006 proposal.
=== Launch === The chain was announced in July 2023. The first CosMc's store opened on December 7, 2023 in the village of Bolingbrook, Illinois. The opening day saw a large queue of customers in the drive-thru which was the only way to order through the restaurant. CNN reported that the Bolingbrook location saw more than twice the number of visits for a typical McDonald's location, citing data from Placer.ai, with the customer base largely skewed to those aged 22–29. At the time of launch, McDonald's planned to have ten operational stores, including nine in Texas by 2024. McDonald's CEO Chris Kempczinski said that the company would evaluate the ten stores as a "limited test”, adding "Let's not get too excited." In its first month, the store reportedly had twice the traffic of a regular McDonald's. A new app and rewards program, CosMc’s Club, along with mobile ordering, was introduced in May 2024. In early 2025, the company announced it would close three of its larger format locations and open two smaller locations in Texas.
Potent and selective MMP-3 inhibitors have been developed by using a hydroxypyrone as the zinc binding group. By attaching an aryl backbone to the 2-position of the pyrone ring, more selectivity was gained. On the hydroxypyrone ring, three positions are available to attach backbones, position 2-, 5- and 6-. Hydroxypyrone-based MMP inhibitors are structurally corresponding to the pyrimidinetriones. A recent inhibitor is the compound 3-hydroxypyran-4-one nominated 868368-30-3. It is MMP-3 selective and its 0,0-bidentate chelation of zinc is the structural part proposed to be responsible for the MMP recognition.
Sources: en.wikipedia.org
While agreeing with the editorial's conclusion, a reply noted that its finding in the negative was guaranteed, given that "global dose estimates or results of mathematical modelling are too inaccurate to be used as dose values for an individual veteran", and that, as of April 2001, no practical method of measuring the expected small doses that each individual veteran would receive had been suggested. The author of the reply, a radiation scientist, went on to suggest a method that had been used several times before, including after the 1986 Chernobyl accident. Despite the widespread use of DU in the Iraq War, at least a year after the conflict began, testing of UK troops was still only in the discussion phase. The Royal Society Working Group on the Health Hazards of Depleted Uranium Munitions (RSDUWG) concluded in 2002 that there were "very low" health risks associated with the use of depleted uranium, though it also ventured that, "[i]n extreme conditions and under worst-case assumptions" lung and kidney damage could occur, and that in "worst-case scenarios high local levels of uranium could occur in food or water that could have adverse effects on the kidney". In 2003, the Royal Society issued another urgent call to investigate the actual health and environmental impact of depleted uranium. The same year, a cohort study of Gulf War veterans found no elevated risks of cancer generally, nor of any specific cancers in particular, though recommended follow up studies.
==== Upward wealth transfer ==== The Atlantic, CNBC, The New York Times, and Vox argued that the bill would create the largest upward transfer of wealth from the poor to the rich in American history, with Fortune and CNN nicknaming it the "Reverse Robin Hood Bill", Senate Minority Leader Chuck Schumer (D-NY) mockingly called the bill the "We're All Going to Die Act", alluding to comments made by Republican Senator Joni Ernst (R-IA) at a town hall.
== Green bean chips == Green bean chips may be prepared mixed with olive oil and seasonings, which are placed on a baking pan and baked until they are crisp. They may be prepared by freeze-drying green beans that are then vacuum-fried. Per a one-ounce (30 g) serving, green bean chips contain 130 calories, 4.5 g fat and 5 g fiber.
Figures 1 and 2 show two-dimensional projections of a phase diagram. In the pressure-temperature phase diagram (Fig. 1) the boiling curve separates the gas and liquid region and ends in the critical point, where the liquid and gas phases disappear to become a single supercritical phase. The appearance of a single phase can also be observed in the density-pressure phase diagram for carbon dioxide (Fig. 2). At well below the critical temperature, e.g., 280 K, as the pressure increases, the gas compresses and eventually (at just over 40 bar) condenses into a much denser liquid, resulting in the discontinuity in the line (vertical dotted line). The system consists of 2 phases in equilibrium, a dense liquid and a low density gas. As the critical temperature is approached (300 K), the density of the gas at equilibrium becomes higher, and that of the liquid lower. At the critical point (304.1 K (31.0 °C; 87.7 °F) and 7.38 MPa (73.8 bar)), there is no difference in density, and the two phases become one fluid phase. Thus, above the critical temperature a gas cannot be liquefied by pressure. At slightly above the critical temperature (310 K), in the vicinity of the critical pressure, the line is almost vertical. A small increase in pressure causes a large increase in the density of the supercritical phase. Many other physical properties also show large gradients with pressure near the critical point, e.g. viscosity, the relative permittivity and the solvent strength, which are all closely related to the density.
Incandescent lamps are very sensitive to changes in the supply voltage. These characteristics are of great practical and economic importance. For a supply voltage V near the rated voltage of the lamp:
Sources: en.wikipedia.org
==== Aspartic acid ==== Aspartic acid (aspartate) is one of the most common amino acids in the typical diet. As with methanol and phenylalanine, intake of aspartic acid from aspartame is less than would be expected from other dietary sources. At the 90th percentile of intake, aspartame provides only between 1% and 2% of the daily intake of aspartic acid.
== Further reading == García-Colín, L.S.; Velasco, R.M.; Uribe, F.J. (August 2008). "Beyond the Navier–Stokes equations: Burnett hydrodynamics". Physics Reports. 465 (4): 149–189. Bibcode:2008PhR...465..149G. doi:10.1016/j.physrep.2008.04.010.
=== Side effects === Side effects after intravenous TRH administration are minimal. Nausea, flushing, urinary urgency, and mild rise in blood pressure have been reported. After intrathecal administration, shaking, sweating, shivering, restlessness, and mild rise in blood pressure were observed.
=== D11AX Other dermatologicals === D11AX01 Minoxidil D11AX02 Gamolenic acid D11AX03 Calcium gluconate D11AX04 Lithium succinate D11AX05 Magnesium sulfate D11AX06 Mequinol D11AX08 Tiratricol D11AX09 Oxaceprol D11AX10 Finasteride D11AX11 Hydroquinone D11AX12 Pyrithione zinc D11AX13 Monobenzone D11AX16 Eflornithine D11AX18 Diclofenac D11AX21 Brimonidine D11AX22 Ivermectin D11AX23 Aminobenzoate potassium D11AX24 Deoxycholic acid D11AX25 Hydrogen peroxide D11AX26 Caffeine D11AX27 Oxymetazoline D11AX52 Gamolenic acid, combinations D11AX57 Collagen, combinations QD11AX90 Benzoylperoxide
"Eat Mor Chikin" is the chain's most prominent advertising slogan, created by The Richards Group in 1995. The slogan is often seen in advertisements featuring Holstein dairy cows that are often seen wearing (or holding) signs that (usually) read "Eat Mor Chikin" in capital letters. The ad campaign was temporarily halted on January 1, 2004, during a mad cow disease scare, so as not to make the chain seem insensitive or appear to be taking advantage of the scare to increase its sales. Two months later, the cows were put up again. The cows replaced the chain's old mascot, Doodles, an anthropomorphized chicken that still appears as the C on the logo. Chick-fil-A vigorously protects its intellectual property, sending cease and desist letters to those they think have infringed on their trademarks. The corporation has successfully protested at least 30 instances of the use of an "eat more" phrase, saying that the use would cause confusion of the public, dilute the distinctiveness of their intellectual property, and diminish its value. A 2011 letter to Vermont artist Bo Muller-Moore who screen prints T-shirts reading: "Eat More Kale" demanded that he cease printing the shirts and turn over his website. The incident drew criticism from Vermont governor Peter Shumlin, and created backlash against what he termed Chick-fil-A's "corporate bullying". On December 11, 2014, Bo Muller-Moore announced that the U.S. Patent Office granted his application to trademark his "Eat More Kale" phrase.
Sources: en.wikipedia.org
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.
Acidification lowers pH and slows thiol oxidation during handling. It also helps precipitate proteins that could interfere with detection. Typical choices include metaphosphoric acid and sulfosalicylic acid.
Dissolved oxygen reacts with the thiol group, forming glutathione disulfide. Neutral and alkaline conditions generally increase the oxidation rate. Light, metal ions, and repeated freezing and thawing can also reduce stability.
Glutathione is built from three amino acids: glutamate, cysteine, and glycine. The linkage involves the gamma-carboxyl group of glutamate rather than the alpha-carboxyl group, which is unusual for peptides. This structure protects the bond from some common peptidases.