JCI Insight 5 , e130651 (2020)
Biochemical Functions and Mechanisms Glutathione participates in multiple critical biochemical pathways that make it valuable for diverse research applications: Antioxidant Defense Mechanisms: Direct ROS Scavenging: GSH directly neutralizes reactive oxygen species including hydrogen peroxide, hydroxyl radicals, and lipid peroxides through thiol oxidation Glutathione Peroxidase System: GSH serves as substrate for glutathione peroxidases (GPx enzymes) that catalyze reduction of hydrogen peroxide and organic peroxides Antioxidant Regeneration: GSH reduces oxidized vitamin C (dehydroascorbate) and vitamin E (tocopheryl radical), regenerating these antioxidants Metal Ion Chelation: GSH binds redox-active metal ions (iron, copper) preventing Fenton reactions that generate hydroxyl radicals Redox Signaling: The GSH/GSSG ratio regulates redox-sensitive transcription factors, kinases, and phosphatases involved in cellular signaling Detoxification and Xenobiotic Metabolism: Glutathione S-Transferase Reactions: GSH conjugates with electrophilic xenobiotics, drugs, and metabolites through GST-catalyzed reactions Phase II Detoxification: GSH conjugation represents a major Phase II detoxification pathway for numerous environmental toxins and pharmaceutical compounds Heavy Metal Detoxification: GSH forms complexes with heavy metals (mercury, cadmium, lead) facilitating their removal Reactive Aldehyde Scavenging: GSH neutralizes reactive aldehydes including 4-hydroxynonenal and malondialdehyde produced during lipid peroxidation Drug Metabolism: GSH participates in biotransformation of acetaminophen, cisplatin, and numerous other therapeutic agents Cellular Regulatory Functions: Protein Thiol Protection: GSH maintains protein cysteine residues in reduced state preventing aberrant disulfide formation S-Glutathionylation: Reversible protein modification regulating enzyme activity, transcription factors, and signaling molecules Immune Function Modulation: GSH levels regulate lymphocyte proliferation, cytokine production, and T-cell function Apoptosis Regulation: GSH depletion sensitizes cells to apoptotic stimuli while maintenance promotes cell survival DNA Synthesis: GSH provides reducing equivalents for ribonucleotide reductase essential for DNA synthesis Cellular Distribution and Compartmentalization Glutathione distribution varies significantly across cellular compartments, with important implications for research applications: Intracellular Glutathione Concentrations: Cytosol: 1-11 mM (highest concentration, 80-85% of total cellular GSH) Mitochondria: 5-11 mM (critical for mitochondrial function) Nucleus: 3-15 mM (protects DNA from oxidative damage) Endoplasmic Reticulum: 1-3 mM (more oxidized ratio, GSH:GSSG ~3:1) Peroxisomes: High GSH content (involved in fatty acid oxidation) Organ-Specific Distribution: Liver: Highest tissue GSH concentrations (5-10 mM), reflecting major detoxification role Kidney: High GSH levels supporting filtration and reabsorption functions Lung: Elevated GSH in epithelial lining fluid protecting against inhaled oxidants Brain: Region-specific GSH distribution with high levels in glia cells Erythrocytes: Substantial GSH content (2-3 mM) protecting hemoglobin from oxidation This compartmentalization is maintained by specific transporters and synthesis machinery, with research investigating mechanisms controlling GSH distribution and transport between compartments
The key ingredient glutathione acts as an antioxidant and helps reduce free radical damage to body cells
The best fit is often a healthy adult near a stable weight, with localized subcut
For Canadians managing the stressors of modern life, glutathione is a critical line of defence
Another group of non-enzymatic antioxidants, carotenoids, are pigment molecules which give many fruits and vegetables their vibrant colors and include well-known variants such as beta-carotene, lycopene, lutein, and zeaxanthin [56]
