Superoxide dismutase glutathione metabolism

The red cell contains a battery of cytosolic enzymes, such as superoxide dismutase, catalase, and glutathione peroxidase, to dispose of powerful oxidants generated during its metabolism. 

In 1969, McCord and Fridovich discovered that a copper-containing protein, erythrocuprein, isolated from red blood cells, catalyzed the dismutation of superoxide O - [17]. This enzyme was renamed superoxide dismutase (SOD). A striking positive correlation is now known to exist between the life-span potential of mammal species and the ratio of SOD activity and specific metabolic rate of their tissues [18]. The ubiquitous vitaminE, glutathione peroxidases and superoxide dismutases provide a primary protective barrier against the toxicity of free radicals and peroxides in mammalian cells. 

PHY is metabolized to eseroline which is further hydroxylated to form catechol and its oxidative product rubreserine (o-quinone). Eseroline causes damage to neuronal ceUs. hi another investigation, the changes in antioxidant enzymes were studied in brain regions in response to chronic infusion of PHY (34.5 jig/kg/hr) in rats that were sacrificed at the end of days 1, 7, and 12 of infusion. PHY infusion increased superoxide dismutase (SOD) activity in brain stem (122 and 123% of control) and in striatum (119 and 117% of control) on days 7 and 12, respectively. PHY infusion depressed catalase activity in the brain stem, while glutathione peroxidase activity increased in the brain stem (153 and 151% of control) and in cortex (114 and 138% of control) on days 7 and 12 of PHY infusion, respectively. This study suggests... 

See also Reactive Oxygen, Oxygen Metabolism and Human Disease, Superoxide Dismutase, Catalase, Glutathione Peroxidase... 

Several enzyme systems exist as cellular defense (detoxification) pathways against the chemically reactive metabolites generated by GYP metabolism (91,92,102,103). These include GST, epoxide hydrolase, and quinone reductase, as well as catalase, glutathione peroxidase, and superoxide dismutase, which detoxify the peroxide and superoxide by-products of metabolism. The efficiency of the bioinactivation process is dependent on the inherent chemical reactivity of the electrophilic intermediate, its affinity and selectivity of the reactive metabolite for the bioinactivation enzymes, the tissue expression of these enzymes, and the rapid upregulation of these enzymes and cofactors mediated by the cellular sensors of chemical stress. The reactive metabolites that can evade these defense systems may damage target proteins and nucleic acids by either oxidation or covalent modification. 

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