This is a working overview of GSSG, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2026-06-09. Anything still debated is marked as such rather than presented as settled.
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.
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.
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.
| 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. |
In cells, glutathione exists mainly in a reduced form called GSH. When two GSH molecules react, they form oxidized glutathione, or GSSG, which contains a disulfide bond. The ratio of GSH to GSSG is often used as an indicator of oxidative stress. Enzymes such as glutathione peroxidase and glutathione reductase help cycle the molecule between these two states. This cycling supports antioxidant defense, detoxification of reactive molecules, and regulation of certain signaling pathways.
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.
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 a tripeptide composed of glutamate, cysteine, and glycine. Its glutamate-cysteine linkage uses the gamma-carboxyl group of glutamate, a feature that resists standard peptidases. The cysteine residue provides a thiol group, which gives the molecule its reducing character. In cells, glutathione is often the most abundant small-molecule thiol, with concentrations varying widely by tissue and compartment. It exists mainly in a reduced form called GSH, while oxidation produces a disulfide-linked dimer called GSSG.
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.
89. Mymensingh Med J. 2026 Oct;35(4):1312-1316. Diagnosis of Rhinoentomophthoromycosis in a 55 Years Old Male: A Case Report. Shawrave SA(1), Zoheb SJM, Galib GI, Tanni RZ, Shawon MMR, Bhuiyan MJT. Author information: (1)Dr Shaharior Arafat Shawrave, Associate Professor, Department of ENT and Head Neck Surgery, Dhaka Medical College (DMC), Dhaka, Bangladesh; E-mail: shawrave77@gmail.com. Entomophthoromycosis is a chronic fungal infection characterized by a diverse range of manifestations, including subcutaneous, mucocutaneous and visceral infections. The majority of subcutaneous infections caused by entomophthoralean fungi are attributed to Basidiobolus spp, C. coronatus or C. incongruous. In this report, we present a case of rhinoentomophthoromycosis in a middle-aged, immunocompetent male, primarily affecting the nasopharynx. Initially, the diagnosis posed a dilemma, but it was ultimately confirmed through meticulous examination of microscopy and histopathology of the aspirate. The patient's response to antifungal therapy was favorable. We hereby provide a comprehensive account of this case and discuss the efficacy of Posaconazole in the treatment of rhinoentomophthoromycosis in a 55-year-old male patient with diabetes.
The European Aviation Safety Agency (EASA) is tasked by Article 15(4) of Regulation (EC) No 216/2008 of the European Parliament and of the Council of February 20, 2008, to provide an annual review of aviation safety. The Annual Safety Review presents statistics on European and worldwide civil aviation safety. Statistics are grouped according to type of operation, for instance, commercial air transport, and aircraft category, such as aeroplanes, helicopters, gliders, etc. The Agency has access to accident and statistical information collected by the International Civil Aviation Organization (ICAO). States are required, according to ICAO Annex 13, on Aircraft Accident and Incident Investigation, to report to ICAO information, on accidents and serious incidents to aircraft with a maximum certificated take-off mass (MTOM) over 2250 kg. Therefore, most statistics in this review concern aircraft above this mass. In addition to the ICAO data, a request was made to the EASA Member States to obtain light aircraft accident data. Furthermore, data on the operation of aircraft for commercial air transport were obtained from both ICAO and the NLR Air Transport Safety Institute.
Quantitative studies of enzymatic reactions often found that the acceleration of chemical reaction speed cannot be fully explained by existing theories like the approximation, acid/base catalysis and electrophile/nucleophile catalysis. And there is an obvious paradox: in reversible enzymatic reaction if the active site perfectly fits the substrates then the backward reaction will be slowed since products cannot fit perfectly into the active site. So conformational distortion was introduced and argues that both active site and substrate can undergo conformational changes to fit with each other all the time.
As of 2016, challenges including optimizing sample treatment, optimizing disk surfaces, developing readers that can deploy multiple colors of light delivery and sensing for multiplexing, and for clinical use, obtaining regulatory approvals. The field is similar to lab-on-a-chip platforms. As of 2010 companies including Gyros AB, Tecan, and Burstein Technologies were working on bringing CD/DVD based immunoassays and equipment to market. Bioanalysis Microanalysis Immunoscreening List of chemical analysis methods
Proteomics permits the quantitative analysis and detection of changes to proteins or protein biomarkers. Protein biomarkers detect a variety of biological changes, such as protein-protein interactions, post-translational modifications and immunological responses. Protein biomarkers are widely used in diagnostics due to their direct involvement in cellular functions and pathways. Protein biomarkers can provide direct information about the functional state of cells and tissues, offering insights into disease mechanisms. Techniques such as mass spectrometry, immunohistochemistry, ELISA, and flow cytometry are employed to detect protein biomarkers, which can indicate protein presence and quantification. For example, in about 20% of breast cancers, the cancer cells have an overexpression of the HER2 gene, leading to more aggressive tumor growth. HER2 status can be determined using IHC and FISH. HER2-positive breast cancers are treated with targeted therapies that specifically target the HER2 protein, inhibiting the growth of cancer cells.
Sources: pubmed.ncbi.nlm.nih.gov
Amyloid proteins deposit most commonly inside the knee, followed by hands, wrists, elbow, hip, and ankle, causing joint pain. In males with advanced age (>80 years), there is significant risk of wild-type transthyretin amyloid deposition in synovial tissue of knee joint, but predominantly in old age deposition of wild type transthyretin is seen in cardiac ventricles. ATTR deposits have been found in ligamentum flavum of patients that underwent surgery for lumbar spinal stenosis. In beta 2-microglobulin amyloidosis, males have high risk of getting carpal tunnel syndrome. Aβ2MG amyloidosis (Hemodialysis associated amyloidosis) tends to deposit in synovial tissue, causing chronic inflammation of the synovial tissue in knee, hip, shoulder and interphalangeal joints. Amyloid light chains deposition in shoulder joint causes enlarged shoulders, also known as "shoulder pad sign". Amyloid light chain depositions can also cause bilateral symmetric polyarthritis. The deposition of amyloid proteins in the bone marrow without causing plasma cell dyscrasias is called amyloidoma. It is commonly found in cervical, lumbar, and sacral vertebrae. Those affected may be presented with bone pain due to bone lysis, lumbar paraparesis, and a variety of neurological symptoms. Vertebral fractures are also common.
Afamelanotide, sold under the brand name Scenesse, is a medication used to prevent phototoxicity and to reduce pain from light exposure for people with erythropoietic protoporphyria, a rare form of genetic sun sensitivity. Afamelanotide is a melanocortin 1 receptor (MC1 receptor) agonist and a synthetic peptide and analogue of α-melanocyte stimulating hormone. It is administered as subcutaneous implant. In the European Union, afamelanotide is indicated for the prevention of phototoxicity in adults with erythropoietic protoporphyria. In the United States, afamelanotide is indicated for increasing pain-free light exposure in adults with a history of reactions to light (phototoxicity) from erythropoietic protoporphyria.
c7orf26 (accession: NM_024067 / NP_076972; alias: MGC-2178) is located on the long arm of chromosome 7 (7p22.1), starting at 6590021 and ending at 6608726. The c7orf26 gene spans 2178 base pairs and is orientated on the + strand. The coding region is made up of a protein sequence measuring 449 amino acids long. It is divided into 6 transcripts containing a total of 24 exons on the forward strand and has 5952 unique Single Nucleotide Polymorphisms (SNPs). Genes ZDHHC4, ZNF853 and ZNF316 neighbor c7orf26 on chromosome 7. Gene ZDHHC4 is a zinc-finger protein involved with cytochrome-c oxidase activity and protein-cysteine S-palmitoyltransferase activity and has overlapping regions with c7orf26. Gene GRID2IP lies upstream by >2000 bp of c7orf26, and is heavily involved with in synaptogenesis and synaptic plasticity. c7orf26 is highly expressed in lymphatic, reproductive, and nervous tissue. These include the brain (frontal and occipital cortex), thymus glands, salivary glands, endometrium, cervix, and prostate. It is intermediately expressed in the lungs.
Chlorella vulgaris is a species of green microalga in the division Chlorophyta. This unicellular alga was discovered in 1890 by Martinus Willem Beijerinck as the first microalga with a well-defined nucleus. It is the type species of the genus Chlorella. It is found in freshwater and terrestrial habitats, and has a cosmopolitan distribution. Chlorella vulgaris has a number of potential applications in science, such as biofuel, livestock feed, and wastewater treatment. Beginning in the 1990s, German scientists noticed the high protein content of C. vulgaris and began to consider it as a new food source. Japan is currently the largest consumer of Chlorella, both for nutritional and therapeutic purposes, and it is used as a dietary supplement or protein-rich food additive in several countries worldwide. C. vulgaris is a green eukaryotic microalga. The cells are 4–10 μm in diameter, and are spherical. The chloroplast (chromatophore) is pea-green in color and cup-shaped, with a single pyrenoid.
Sources: en.wikipedia.org
The terms "active" and "passive" are simple but important terms in the world of automotive safety. "Active safety" is used to refer to technology assisting in the prevention of a crash and "passive safety" to components of the vehicle (primarily airbags, seatbelts and the physical structure of the vehicle) that help to protect occupants during a crash. Crash avoidance systems and devices help the driver — and, increasingly, help the vehicle itself — to avoid a collision. This category includes: The vehicle's headlamps, reflectors, and other lights and signals The vehicle's mirrors The vehicle's brakes, steering, and suspension systems A subset of crash avoidance is driver assistance systems, which help the driver to detect obstacles and to control the vehicle. Driver assistance systems include:
Patients with Type II diabetes will have elevated glucagon levels during a fast and after eating. These elevated glucagon levels over stimulate the liver to undergo gluconeogenesis, leading to elevated blood glucose levels. Consistently high blood glucose levels can lead to organ damage, neuropathy, blindness, cardiovascular issues and bone and joint problems. It is not entirely clear why glucagon levels are so high in patients with Type II diabetes. One theory is that the alpha cells have become resistant to the inhibitory effects of glucose and insulin and do not respond properly to them. Another theory is that nutrient stimulation of the gastrointestinal tract, thus the secretion of gastric inhibitory polypeptide and Glucagon-like peptide-1, is a very important factor in the elevated secretion of glucagon.
Although they are classically thought of working only together, GPCRs may signal through G-protein-independent mechanisms, and heterotrimeric G-proteins may play functional roles independent of GPCRs. GPCRs may signal independently through many proteins already mentioned for their roles in G-protein-dependent signaling such as β-arrs, GRKs, and Srcs. Such signaling has been shown to be physiologically relevant, for example, β-arrestin signaling mediated by the chemokine receptor CXCR3 was necessary for full efficacy chemotaxis of activated T cells. In addition, further scaffolding proteins involved in subcellular localization of GPCRs (e.g., PDZ-domain-containing proteins) may also act as signal transducers. Most often the effector is a member of the MAPK family.
Tranexamic acid can be used in skincare products as a cosmetic active to reduce the appearance of inflammation and hyperpigmentation. Tranexamic acid is a zwitterion amino acid, and has a low permeability coefficient in the stratum corneum. Tranexamic acid can be combined with penetration enhancers and microneedling to overcome this limitation. Cosmetic uses may also employ lipophilic derivatives of tranexamic acid (ester prodrugs like Cetyl tranexamate mesylate) that are not zwitterionic and thus have improved skin permeability. Allergic to tranexamic acid History of seizures History of venous or arterial thromboembolism or active thromboembolic disease Severe kidney impairment due to accumulation of the medication, dose adjustment is required in mild or moderate kidney impairment
Much of the genetic manipulation done in CHO cells is done in cells lacking DHFR enzyme. This genetic selection scheme remains one of the standard methods to establish transfected CHO cell lines for the production of recombinant therapeutic proteins. The process begins with the molecular cloning of the gene of interest and the DHFR gene into a single mammalian expression system. The plasmid DNA carrying the two genes is then transfected into cells, and the cells are grown under selective conditions in a thymidine-lacking medium. Surviving cells will have the exogenous DHFR gene along with the gene of interest integrated in its genome. The growth rate and the level of recombinant protein production of each cell line varies widely. To obtain a few stably transfected cell lines with the desired phenotypic characteristics, evaluating several hundred candidate cell lines may be necessary. The CHO and CHO-K1 cell lines can be obtained from a number of biological resource centres such as the European Collection of Cell Cultures, which is part of the Health Protection Agency Culture Collections. These organizations also maintain data, such as growth curves, timelapse videos of growth, images, and subculture routine information.
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.
GSH is the reduced, thiol-containing form of glutathione, while GSSG is the oxidized disulfide dimer formed when two GSH molecules react. Cells maintain a high GSH-to-GSSG ratio under normal conditions. A shift toward GSSG is often interpreted as oxidative stress, though sample handling can affect the measured ratio.