If you have been reading about redox and want a single page that covers the useful parts, this is it: definitions, context, how it is studied, and the questions that come up repeatedly.
Last reviewed on 2026-01-09. Where a claim depends on a specific study, the study is described rather than over-claimed.
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.
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 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.
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.
| Property | Value | Notes |
|---|---|---|
| Molecular formula | C10H17N3O6S | Reduced glutathione (GSH); oxidized form differs by disulfide linkage. |
| Molar mass | 307.32 g/mol | Calculated for the reduced tripeptide. |
| Appearance | White to off-white crystalline powder | Typical laboratory reagent description. |
| Solubility | Soluble in water | Aqueous solutions are acidic; solubility depends on pH and salt form. |
| CAS Registry Number | 70-18-8 | Refers to reduced L-glutathione; oxidized form has a different number. |
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 synthesis proceeds in two ATP-dependent steps catalyzed by glutamate-cysteine ligase and glutathione synthetase. The first step joins glutamate and cysteine to form gamma-glutamylcysteine and is generally rate-limiting. The second step adds glycine to complete the tripeptide. Cysteine availability, feedback inhibition by glutathione, and oxidative conditions influence flux through this pathway. The pathway is conserved across many organisms, and degradation by gamma-glutamyl transpeptidase and related peptidases recycles amino acids for new synthesis.
Within cells, glutathione serves as a cofactor for glutathione peroxidases and glutathione S-transferases. These enzymes reduce hydrogen peroxide and organic peroxides or conjugate electrophilic compounds to the thiol group. The resulting conjugates can be exported and processed through mercapturic acid pathways. Glutathione also contributes to protein thiol homeostasis and to recycling of other antioxidants such as ascorbate. Its precise roles vary by tissue, and many regulatory effects observed in laboratory systems remain difficult to quantify in whole organisms.
The branch extended to the Mezhdunarodnaya station in 2006; all work on the third station, Dorogomilovskaya (between Kiyevskaya and Delovoi Tsentr), has been postponed. The branch is planned for extension as far as the Savyolovskaya station, on the Serpukhovsko-Timiryazevskaya Line. On 5 March 2021, the company MTS announced the launch of the country's first pilot 5G network in Moscow.
CoA-glutathione + glutathione Thus, the two substrates of this enzyme are CoA and glutathione disulfide, whereas its two products are CoA-glutathione and glutathione. This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with a disulfide as acceptor. The systematic name of this enzyme class is CoA:glutathione-disulfide oxidoreductase. Other names in common use include glutathione-coenzyme A glutathione disulfide transhydrogenase, glutathione-coenzyme A glutathione disulfide transhydrogenase, glutathione coenzyme A-glutathione transhydrogenase, glutathione:coenzyme A-glutathione transhydrogenase, coenzyme A:oxidized-glutathione oxidoreductase, and coenzyme A:glutathione-disulfide oxidoreductase. This enzyme participates in cysteine metabolism and glutathione metabolism.
=== Transgender hormone therapy === Finasteride is sometimes used as an antiandrogen in feminizing hormone therapy for transfeminine people. There are limited clinical data on finasteride for this use and some authorities explicitly recommend against its routine use. Relatedly, the medication is considered to be limitedly useful and unnecessary in transfeminine people with testosterone levels in the normal female range. However, finasteride may be helpful in those with higher testosterone levels and symptoms like scalp hair loss and excessive body hair or who seek only partial feminization. Besides transfeminine people, finasteride is helpful in transmasculine people for preventing scalp hair loss and is better-established for this purpose, though it might impede masculinization such as clitoral growth and development of facial and body hair.
Sources: en.wikipedia.org
Oral, intravenous, intra-arterial, or intramuscular routes of protein administration are not always as effective, as the therapeutic protein may be metabolized or cleared before it can enter the target tissue. Cell-based pro-angiogenic therapies are still early stages of research, with many open questions regarding best cell types and dosages to use.
A third family of alcohol dehydrogenases, unrelated to the above two, are iron-containing ones. They occur in bacteria and fungi. In comparison to enzymes of the above families, these enzymes are oxygen-sensitive. Members of the iron-containing alcohol dehydrogenase family include:
== Structure == Although engineered and modified in a laboratory setting, ELPs share structural characteristics with intrinsically disordered proteins (IDPs) naturally found in the body, such as tropoelastin, from which ELPs were given their name. The repeat sequences found in the biopolymer give each ELP a distinct structure, as well as influence the lower critical solution temperature (LCST), also referred to commonly as the Tt. It is at this temperature that the ELPs move from a linear, relatively disordered state to a more densely aggregated, partially ordered state Although given as a single temperature, Tt, the ELP phase change process generally begins and ends within a temperature range of approximately 2 °C. Also, Tt is altered by the addition of unique proteins to the free ELPs.
Sources: en.wikipedia.org
=== Classification criteria === In 2010, the 2010 ACR / EULAR Rheumatoid Arthritis Classification Criteria were introduced. The new criteria are not diagnostic criteria, but are classification criteria to identify disease with a high likelihood of developing a chronic form. However a score of 6 or greater unequivocally classifies a person with a diagnosis of rheumatoid arthritis. These new classification criteria overruled the "old" ACR criteria of 1987 and are adapted for early RA diagnosis. The "new" classification criteria, jointly published by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR), establish a point value between 0 and 10. Four areas are covered in the diagnosis:
The analysis of the entire complement of phosphorylated proteins in a cell is certainly a feasible option. This is due to the optimization of enrichment protocols for phosphoproteins and phosphopeptides, better fractionation techniques using chromatography, and improvement of methods to selectively visualize phosphorylated residues using mass spectrometry. Although the current procedures for phosphoproteomic analysis are greatly improved, there is still sample loss and inconsistencies with regards to sample preparation, enrichment, and instrumentation. Bioinformatics tools and biological sequence databases are also necessary for high-throughput phosphoproteomic studies.
Benzophenone is a naturally occurring organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. Benzophenone has been found in some fungi, fruits and plants, including grapes. It is a white solid with a low melting point and rose-like odor that is soluble in organic solvents. Benzophenone is the simplest diaromatic ketone. It is a widely used building block in organic chemistry, being the parent diarylketone.
However, a 2015 estimate that used a new method for calibrating molecular clocks confirmed that while modern birds originated early in the Late Cretaceous, likely in Western Gondwana, a pulse of diversification in all major groups occurred around the Cretaceous–Palaeogene extinction event. Modern birds would have expanded from West Gondwana through two routes. One route was an Antarctic interchange in the Paleogene. The other route was probably via Paleocene land bridges between South America and North America, which allowed for the rapid expansion and diversification of Neornithes into the Holarctic and Paleotropics. On the other hand, the occurrence of Asteriornis in the Northern Hemisphere suggest that Neornithes dispersed out of East Gondwana before the Paleocene.
Sources: en.wikipedia.org
GSH is the reduced form of glutathione, with a free thiol group on cysteine. GSSG is the oxidized disulfide form, created when two GSH molecules become linked. The two forms exist together, and their balance is often reported as the GSH/GSSG ratio in laboratory studies.
Glutathione is synthesized inside cells from amino acids rather than being classified as an essential dietary nutrient. Dietary sources can provide glutathione or its precursors, but digestion and absorption alter what reaches tissues. Research continues on how dietary intake relates to cellular glutathione levels.
The liver has high glutathione concentrations and uses the compound in conjugation and antioxidant reactions. These reactions are relevant to the processing of drugs, pollutants, and normal metabolic byproducts. Studies often examine liver glutathione as a marker of oxidative stress or detoxification capacity.
It is a tripeptide of glutamate, cysteine, and glycine. The glutamate-cysteine bond is unusual because it forms through the gamma-carboxyl group.