The contribution of GSH peroxidase-1, catalase and GSH to the degradation of H2O2 by the mouse lens.
Utilizing cultured lenses from normal and homozygous glutathione peroxidase (GSHPx-1) knockout mice and inhibitors for GSSG Reductase (GSSG Red), 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU) and catalase (Cat), 3-aminotriazole (3-AT), the ability to degrade H2O2 was examined at two H2O2 concentrations, 300 microM and 80 microM. It was found that GSHPx-1 contributed about 15% to the H2O2 degradation. The Cat contribution was concentration dependent being about 30% at 300 microM H2O2 and approximately 8% to 15% at 80 microM H2O2. GSH loss measured as nonprotein thiol (NP-SH) was shown to be linked to most of the remaining H2O2 degradation accounting for about 54% to 72% of the H2O2 degradation at 300 microM and 80 microM, respectively. However, based on evaluation of the ability of GSH to nonenzymatically degrade H2O2, it can only account for about 36% at 300 microM and 19% at 80 microM H2O2 of the observed lens H2O2 degradation. It is, therefore, concluded that lens GSH must be involved in other reactions either directly or indirectly related to H2O2 degradation.
Spector
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A
Department of Ophthalmology, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA.
Ma
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Wang
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Yang
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Ho
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D000640:Amitrole / Q000494:pharmacology; D000818:Animals; D002374:Catalase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism*; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007908:Lens, Crystalline / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009607:Nitrosourea Compounds / Q000494:pharmacology; D018384:Oxidative Stress
D009607:Nitrosourea Compounds; D006861:Hydrogen Peroxide; D002374:Catalase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005978:Glutathione; D000640:Amitrole