This is a working overview of glutathione, written for readers who want more than a one-paragraph summary but less than a textbook.
This page was last updated on 2025-09-05 and is reviewed periodically as new material appears.
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.
Glutathione is a tripeptide composed of glutamate, cysteine, and glycine. It occurs in nearly all living cells, with highest concentrations in liver, kidney, and red blood cells, and exists in reduced (GSH) and oxidized disulfide (GSSG) forms. The cysteine thiol group enables reversible oxidation and reduction reactions. This property makes glutathione a central participant in cellular redox balance. The balance between these forms is often used as an indicator of oxidative stress.
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.
Glutathione participates in detoxification reactions, amino acid transport, and the maintenance of protein thiols. It serves as a cofactor for several enzymes, including glutathione peroxidases and glutathione S-transferases. In research literature, altered glutathione status appears in studies of aging, infection, metabolic stress, and environmental exposure. Whether low glutathione is a cause, consequence, or marker of such conditions often remains unresolved. Direct measurement in blood or tissue provides a snapshot, but results depend on sample handling, timing, and the method used.
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.
| Property | Value | Notes |
|---|---|---|
| Common name | Glutathione | Reduced form is abbreviated GSH |
| Chemical class | Tripeptide | Composed of glutamate, cysteine, and glycine |
| Molar mass | 307.32 g/mol | For reduced glutathione |
| CAS Registry Number | 70-18-8 | For reduced L-glutathione |
| Appearance | White crystalline powder | Typical solid reference material |
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.
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.
Glutathione is a small tripeptide built from glutamic acid, cysteine, and glycine. Its peptide bond between glutamate and cysteine involves the gamma-carboxyl group rather than the usual alpha-carboxyl group. This structure gives the molecule a reactive thiol on the cysteine residue. The reduced form, often abbreviated GSH, is the predominant intracellular species in many cell types. Because the thiol can donate electrons, glutathione participates in redox chemistry and in the conjugation of reactive molecules.
Cells synthesize glutathione through two ATP-dependent steps: glutamate-cysteine ligase joins glutamate and cysteine, and glutathione synthetase adds glycine to form the complete tripeptide. Breakdown occurs through gamma-glutamyl transpeptidase and subsequent peptidase reactions, forming the gamma-glutamyl cycle. Within cells, glutathione also forms a disulfide-linked dimer called GSSG when two GSH molecules react. The balance between GSH and GSSG is widely used as an indicator of oxidative conditions, although the ratio can vary by compartment and tissue.
== Prophenolxidase activation system == The phenoloxidase system begins with the recognition of microbial PAMPs (pathogen-associated molecular patterns) including LPS (gram-negative bacteria), peptidoglycans (gram-positive bacteria) and β-1,3-glucans (fungi). Interaction of PAMPs with PRPs (pattern-recognition proteins) activates a series of serine proteinases and those proteolytically cleave the prophenoloxidase (proPO) zymogen and activate phenoxidase (PO). During the proPO system activation, reactive intermediates such as quinone-like intermediates, reactive oxygen (ROI) or nitrogen intermediates are produced. These have cytotoxic activity against microorganisms, prevent organism from entering of another pathogen and also assist in wound healing.
=== Fast === Fast COLD-PCR differs from Full COLD-PCR in that the denaturation and intermediate annealing stages are skipped. This is because, in some cases, the preferential amplification of the mutant DNA is so great that ensuring the formation of the mutant/wildtype heteroduplex DNA is not needed. Thus the denaturation can occur at the Tc, proceed to primer annealing, and then polymerase-mediated extension. Each round of amplification will include these three stages in that order. By utilizing the lower denaturation temperature, the reaction will discriminate toward the products with the lower Tm – i.e. the variant alleles. Fast COLD-PCR produces much faster results due to the shortened protocol, while Full COLD-PCR is essential for amplification of all possible mutations in the starting mixture of DNA. Two-round COLD-PCR is a modified version of Fast COLD-PCR. During the second round of Fast COLD-PCR nested primers are used. This improves the sensitivity of mutation detection compared to one-round Fast COLD-PCR.
On April 24, 2025, during the first Armenian Genocide Remembrance Day of Trump's second term, the White House issued a statement commemorating the day that did not use the term "genocide". This was seen as a reversal after Joe Biden formally recognized the Armenian genocide in 2021. The second Trump administration continues to avoid using the term "genocide", instead continuing to refer to the events as the Medz Yeghern (Armenian for 'Great Catastrophe') and labeling April 24 as only "Armenian Remembrance Day". On August 8, 2025, Armenian prime minister Nikol Pashinyan and Azerbaijani president Ilham Aliyev signed a peace agreement in a ceremony hosted by President Donald Trump in the White House, aiming to end the more than 35-year conflict between Armenia and Azerbaijan.
==== Bupropion (Wellbutrin) ==== The company was also fined for promoting Wellbutrin (bupropion) – approved at the time for major depressive disorder and also sold as a smoking-cessation aid, Zyban – for weight loss and the treatment of attention deficit hyperactivity disorder, sexual dysfunction and substance addiction. GSK paid doctors to promote these off-label uses, and set up supposedly independent advisory boards and Continuing Medical Education programmes.
=== Peptidyl transfer === Chloramphenicol blocks the peptidyl transfer step of elongation on the 50S ribosomal subunit in both bacteria and mitochondria. Macrolides (as well as inhibiting ribosomal translocation and other potential mechanisms) bind to the 50s ribosomal subunits, inhibiting peptidyl transfer. Streptogramins such as Quinupristin/dalfopristin act synergistically, with dalfopristin, enhancing the binding of quinupristin, as well as inhibiting peptidyl transfer. Quinupristin binds to a nearby site on the 50S ribosomal subunit and prevents elongation of the polypeptide, as well as causing incomplete chains to be released. Geneticin, also called G418, inhibits the elongation step in both prokaryotic and eukaryotic ribosomes. Trichothecene mycotoxins are potent and non selective inhibitors of peptide elongation.
Sources: en.wikipedia.org
Aside from adult transgender people, CPA has also been used as a puberty blocker and hence as an antiandrogen and antiestrogen to suppress puberty in transgender adolescents, although GnRH modulators are primarily used and more effective for this purpose.
=== Lymphangioleiomyomatosis === In May 2015, the FDA approved sirolimus to treat lymphangioleiomyomatosis (LAM), a rare, progressive lung disease that primarily affects women of childbearing age. This made sirolimus the first drug approved to treat this disease. LAM involves lung tissue infiltration with smooth muscle-like cells with mutations of the tuberous sclerosis complex gene (TSC2). Loss of TSC2 gene function activates the mTOR signaling pathway, resulting in the release of lymphangiogenic growth factors. Sirolimus blocks this pathway. The safety and efficacy of sirolimus treatment of LAM were investigated in clinical trials that compared sirolimus treatment with a placebo group in 89 patients for 12 months. The patients were observed for 12 months after the treatment had ended. The most commonly reported side effects of sirolimus treatment of LAM were mouth and lip ulcers, diarrhea, abdominal pain, nausea, sore throat, acne, chest pain, leg swelling, upper respiratory tract infection, headache, dizziness, muscle pain and elevated cholesterol. Serious side effects including hypersensitivity and swelling (edema) have been observed in renal transplant patients. While sirolimus was considered for treatment of LAM, it received orphan drug designation status because LAM is a rare condition. The safety of LAM treatment by sirolimus in people younger than 18 years old has not been tested.
=== Eligibility of minors === While the WPATH standards of care generally require the patient to have reached the age of medical majority, they include a separate section devoted to children and adolescents. Prepubescent children do not have access to medical intervention for gender-affirming therapy. After puberty, some medical intervention is available for adolescents depending on specific criteria for gender incongruence diagnosis, capacity for informed consent, and mental and physical health. According to a study by JAMA Pediatrics published in January 2025, less than 0.1% of adolescents covered by private medical insurance in the US take gender-affirming medication to treat gender dysphoria.
Focal or diffuse diffusion-restriction involving the cerebral cortex or basal ganglia. The most characteristic and striking cortical abnormality has been called "cortical ribboning" or "cortical ribbon sign" due to hyperintensities resembling ribbons appearing in the cortex on MRI. The involvement of the thalamus can be found in sCJD, is even stronger and constant in vCJD. Varying degree of symmetric T2 hyperintense signal changes in the basal ganglia (i.e., caudate and putamen), and to a lesser extent globus pallidus and occipital cortex. Brain FDG PET-CT tends to be markedly abnormal, and is increasingly used in the investigation of dementias.
Sources: en.wikipedia.org
Hydromorphone is available in parenteral, rectal, subcutaneous, and oral formulations, and also can be administered via epidural or intrathecal injection. Hydromorphone also has been administered via nebulization to treat shortness of breath, but it is not used as a route for pain control due to low bioavailability. Transdermal delivery systems are also under consideration to induce local skin analgesia. Concentrated aqueous solutions of hydromorphone hydrochloride have a visibly different refractive index from pure water, isotonic 9‰ (0·9 per cent) saline and the like, especially when stored in clear ampoules and phials may acquire a slight clear amber discolouration upon exposure to light; this reportedly has no effect on the potency of the solution, but 14-dihydromorphinones such as hydromorphone, oxymorphone, and relatives come with instructions to protect from light. Ampoules of solution which have developed a precipitate should be discarded. Battery-powered intrathecal drug delivery systems are implanted for chronic pain when other options are ruled out, such as surgery and traditional pharmacotherapy, provided that the patient is considered a suitable fit in terms of any contraindications, both physiological and psychological. An extended-release (once-daily) version of hydromorphone is available in the United States. Previously, an extended-release version of hydromorphone, Palladone, was available before being voluntarily withdrawn from the market after a July 2005 FDA advisory warned of a high overdose potential when taken with alcohol.
Nicergoline is an ergot alkaloid derivative that acts as a potent and selective α1A-adrenergic receptor antagonist. The IC50 of nicergoline in vitro has been reported to be 0.2 nM. The primary action of nicergoline is to increase arterial blood flow by vasodilation. Furthermore, it is known that nicergoline inhibits platelet aggregation. Studies have shown that nicergoline also increases nerve growth factor in the aged brain. In addition to the α1A-adrenergic receptor, nicergoline is an antagonist of the serotonin 5-HT1A receptor (IC50 = 6 nM) and shows moderate affinity for serotonin 5-HT2 and α2-adrenergic receptors and low affinity for the dopamine D1 and D2 and muscarinic acetylcholine M1 and M2 receptors.
12 July – NASA releases the first suite of images from the now fully operational James Webb Space Telescope, a day after releasing the Webb's First Deep Field, the image of early universe with the highest resolution. On 14 July, NASA presents images of Jupiter and related areas captured, for the first time, and including infrared views, by the telescope. On 19 July, scientists report what could be the earliest and most distant galaxy ever discovered, GLASS-z12. 13 July The discovery of fast radio burst FRB 20191221A with an unusually long duration of three seconds is reported. A study affirms (see 7 March) that critical slowing down indicators suggest that tropical, arid and temperate forests are substantially losing resilience. On 4 July, Brazil's INPE reports that the country's regions of the Amazon rainforest have been deforested by a record amount in the first half of 2022. A study shows that blood cells' loss of the Y chromosome in a subset of cells, reportedly affecting at least 40% of 70 years-old men to some degree, contributes to fibrosis, heart risks, and mortality in a causal way. Researchers report the development of semitransparent solar cells that are as large as windows, after team members achieved record efficiency with high transparency in 2020. On 4 July, researchers report the fabrication of solar cells with a record average visible transparency of 79%, being nearly invisible.
Sources: en.wikipedia.org
GSH is the reduced thiol form, while GSSG is the disulfide-linked oxidized dimer. The GSH:GSSG ratio is used as a redox indicator, though the ratio can vary with sample handling and cell type.
Glutathione is present in many foods, including meats, poultry, fish, some vegetables, and fruits. Cooking, storage, and digestion affect the amounts available for absorption.
Yes, both enzymatic steps in glutathione synthesis consume ATP. The first step, catalyzed by glutamate-cysteine ligase, is usually rate-limiting.
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.