A practical reference on redox buffering: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
Reviewed 2025-12-31. Anything still debated is marked as such rather than presented as settled.
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.
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.
| Property | Value | Notes |
|---|---|---|
| Chemical formula | C10H17N3O6S | Reduced glutathione (GSH) |
| Molar mass | 307.32 g/mol | Calculated for C10H17N3O6S |
| Appearance | White to off-white powder | Typical solid form |
| Solubility | Water-soluble | Polar tripeptide |
| Common synonyms | GSH; L-glutathione | Gamma-glutamylcysteinylglycine |
While APHL primarily focuses on public health laboratories in the United States, their global health program makes an effort to help other countries strengthen their own laboratory practices.APHL works with more than 30 countries to: Share effective testing procedures Develop laboratory policies Improve the quality of data Train laboratory leaders Utilize information management systems Create strategies to monitor and detect Establish emergency response programs Design training programs APHL also works with public health laboratories around the world to share information on global health crises and promotes cross-border collaboration.
== External links == The LIVEChart of Nuclides – IAEA AlphaDelta: Stable Isotope fractionation calculator Archived 2011-04-02 at the Wayback Machine National Isotope Development Center Reference information on isotopes, and coordination and management of isotope production, availability, and distribution Isotope Development & Production for Research and Applications (IDPRA) U.S. Department of Energy program for isotope production and production research and development Isosciences Archived 2021-01-18 at the Wayback Machine Use and development of stable isotope labels in synthetic and biological molecules
Biosimilar insulins, which have a shorter development timeline of about eight years compared to 12 years for novel biologic drugs, provide a more affordable alternative, with development costs ranging from 10% to 20% of those for new biologics. These products could help improve access to treatment and reduce disparities in insulin availability. The global market for biologic medicines, including insulin, grew from $46 billion in 2002 to $390 billion in 2020, accounting for 28% of the global pharmaceutical market. In the United States, biologics represented 43% of drug expenditures, totaling $211 billion in 2019, with biosimilar spending expected to rise from $5.2 billion in 2019 to nearly $27 billion by 2024. In Europe, biologics accounted for 34% of medicine spending, reaching US$78.6 billion in 2021, with the biosimilar market valued at $8.8 billion. The global human insulin market was valued at $22.9 billion in 2020, while the biosimilar insulin market stood at $2.3 billion, projected to grow to $5.6 billion by 2027. The introduction of biosimilar insulins has increased market competition, offering a cost-effective alternative that could lower treatment costs and reduce strain on healthcare systems. Since the approval of the first biosimilar insulin, interest in the products has increased. However, uncertainty regarding their safety and efficacy has slowed their adoption among healthcare professionals.
== Pharmacology == DL-threo-beta-benzyloxyaspartate (TBOA) is an inhibitor of the excitatory amino acid transporters. Selective inhibitors for EAAT1 have recently been discovered based on 25 combinations of substitutions at the 4 and 7 positions of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromene-3-carbonitril.
Indonesia acquired 26 P-51D/Ks from the departing Netherlands East Indies Air Force in 1949–1950 and later received 35 P-51Ds from the United States in 1960–1961. The Mustangs were used against numerous rebellions during the 1950s, such as the CIA-backed Permesta rebels in 1958–1961. During this period, the Mustang scored the first and (as of 2022) the only aerial victory of the Indonesian Air Force, when on 18 May 1958, a P-51D Mustang piloted by Capt. Ignatius Dewanto shot down a Permesta's Revolutionary Air Force B-26 Invader piloted by Allen Lawrence Pope near Ambon. They were also used against Commonwealth (RAF, RAAF, and RNZAF) forces during the Indonesia–Malaysia confrontation in the early 1960s. Indonesia received a shipment of five or seven Cavalier II Mustangs and one TF-51D (without tip tanks) delivered in 1972–1973 as part of "Peace Pony" program under the Mutual Defense Assistance Act. The last time Mustangs were deployed for military purposes was during the "Wibawa V" exercise at Mount Lawu, Magetan in February 1975. The Indonesian Mustangs were also used for filming Janur Kuning, which was released in 1980. The Mustangs were replaced in 1976. Israel
Sources: en.wikipedia.org
==== MeSH D12.125.070 – amino acids, branched-chain ==== MeSH D12.125.070.075 – aminoisobutyric acids MeSH D12.125.070.577 – isoleucine MeSH D12.125.070.637 – leucine MeSH D12.125.070.950 – valine MeSH D12.125.070.950.100 – 2-amino-5-phosphonovalerate
Paleopathology The African Burial Ground Bioarchaeology and the Center for Bioarchaeological Research National NAGPRA homepage Bones Don't Lie Blog Powered by Osteons Blog Kristina Killgrove's Bioarchaeology Blog at Forbes
Paul Berg, a Nobel laureate in chemistry, wrote to the Senate that "Quackery will always prey on the gullible and uninformed, but we should not provide it with cover from the NIH," and called the office "an embarrassment to serious scientists". Allen Bromley, then-president of the American Physical Society, similarly wrote to Congress that the OAM had "emerged as an undiscriminating advocate of unconventional medicine. It has bestowed the considerable prestige of the NIH on a variety of highly dubious practices, some of which clearly violate basic laws of physics". Leon Jaroff, writing for The New York Times in 1997, described the OAM as "Tom Harkin's folly". In 1995, Wayne Jonas, a promoter of homeopathy and political ally of Harkin, became the director of the OAM, and continued in that role until 1999. In 1997, the NCCAM budget was increased from $12 million to $20 million annually. From 1990 to 1997, use of alternative medicine in the US increased by 25%, with a corresponding 50% increase in expenditures. The OAM drew increasing criticism from eminent members of the scientific community with letters to the Senate Appropriations Committee when discussion of renewal of funding OAM came up. In 1998, the President of the North Carolina Medical Association publicly called for shutting down the OAM. In 1998, NIH director and Nobel laureate Harold Varmus came into conflict with Harkin by pushing to have more NIH control of alternative medicine research. The NIH Director placed the OAM under stricter scientific NIH control.
This involves inspection of a polished slice of a material to determine the density of "track" markings left in it by the spontaneous fission of uranium-238 impurities. The uranium content of the sample has to be known, but that can be determined by placing a plastic film over the polished slice of the material, and bombarding it with slow neutrons. This causes induced fission of 235U, as opposed to the spontaneous fission of 238U. The fission tracks produced by this process are recorded in the plastic film. The uranium content of the material can then be calculated from the number of tracks and the neutron flux. This scheme has application over a wide range of geologic dates. For dates up to a few million years micas, tektites (glass fragments from volcanic eruptions), and meteorites are best used. Older materials can be dated using zircon, apatite, titanite, epidote and garnet which have a variable amount of uranium content. Because the fission tracks are healed by temperatures over about 200 °C the technique has limitations as well as benefits. The technique has potential applications for detailing the thermal history of a deposit.
Sources: en.wikipedia.org
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.
It is present in nearly all cells, with notable amounts in the liver, kidneys, and red blood cells. The highest intracellular concentrations are usually in the millimolar range. Levels differ by tissue, age, and physiological state.
It is not classified as an essential nutrient because cells can synthesize it from amino acids. Dietary sources exist, but their contribution to tissue pools is not fully established. The body's production depends on enzyme activity and precursor availability.
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.