Key Event Overview
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AOPs Including This Key Event
|AOP Name||Event Type||Essentiality|
|Oxidative Stress Leading to Hypertension||KE||Strong|
|Homo sapiens||Homo sapiens||Strong||NCBI|
|Bos taurus||Bos taurus||Strong||NCBI|
|Mus musculus||Mus musculus||Strong||NCBI|
|Rattus norvegicus||Rattus norvegicus||Strong||NCBI|
Level of Biological Organization
How this Key Event works
Glutathione (GSH) oxidation refers to the conversion of reduced glutathione to its oxidized form glutathione disulfide (GSSG) from exposure to oxidative stress. GSH plays an important role as an anti-oxidant in regulating cellular redox homeostasis, and is mainly present in the cell as the reduced form (98%). Deficiency in GSH or a decrease in GSH/GSSG ratio results in decreased anti-oxidant function and increased susceptibility to oxidative stress, thus making it a marker of cellular redox status. An imbalance in GSH/GSSG ratio has been implicated in the onset and progression of human diseases, such as neurodegenerative diseases, cancers, pulmonary diseases and cardiovascular diseases (Ballatori et al., 2009; Kalinina et al., 2014).
How it is Measured or Detected
GSH and GSSG levels can be determined by high-performance liquid chromatography HPLC, capillary electrophoresis, or biochemically in microplates. Several different assays have been designed to measure glutathione in samples. Enzyme recycling is a widely accepted method to determine total glutathione, in which GSH reacts with DTNB (Ellman's reagent) in the presence of glutathione reductase. Glutathione reductase reduces GSSG to GSH, which then reacts with DTNB to produce a yellow colored 5-thio-2-nitrobenzoic acid (TNB), which absorbs at 412 nm (Tipple and Rogers, 2012). Another method uses HPLC separation and fluorometric detection, where iodoactetic acid is added as a thiol akylating agent followed by dansyl chloride derivatization for fluorometric detection. Similarly, monochlorobimane can be added to culture medium in order to form a fluorescent GSH-monochlorobimane adduct that can be measured fluorometrically (Kamencic et al., 2000).
Evidence Supporting Taxonomic Applicability
The concentrations of GSH and GSSG have been shown in tissues of human and laboratory animals, including rats, mice and cows (Chen et al., 2010; Giustarini et al., 2013).
Ballatori, N., Krance, S.M., Notenboom, S., Shi, S., Tieu, K., and Hammond, C.L. (2009). Glutathione dysregulation and the etiology and progression of human diseases. Biol. Chem. 390, 191–214.
Chen, C.-A., Wang, T.-Y., Varadharaj, S., Reyes, L.A., Hemann, C., Talukder, M.A.H., Chen, Y.-R., Druhan, L.J., and Zweier, J.L. (2010). S-glutathionylation uncouples eNOS and regulates its cellular and vascular function. Nature 468, 1115–1118.
Giustarini, D., Dalle-Donne, I., Milzani, A., Fanti, P., and Rossi, R. (2013). Analysis of GSH and GSSG after derivatization with N-ethylmaleimide. Nat. Protoc. 8, 1660–1669.
Kalinina, E.V., Chernov, N.N., and Novichkova, M.D. (2014). Role of glutathione, glutathione transferase, and glutaredoxin in regulation of redox-dependent processes. Biochem. Biokhimii︠a︡ 79, 1562–1583.
Kamencic, H., Lyon, A., Paterson, P.G., and Juurlink, B.H. (2000). Monochlorobimane fluorometric method to measure tissue glutathione. Anal. Biochem. 286, 35–37.
Tipple, T.E., and Rogers, L.K. (2012). Methods for the Determination of Plasma or Tissue Glutathione Levels. Methods Mol. Biol. Clifton NJ 889, 315–324.