Detoxification, reactive oxygen species

Manganese is the cofactor for catalases, peroxidases and superoxide dismutases, which are all involved in the detoxification of reactive oxygen species (SOD). We consider here the widely distributed Mn SOD, and then briefly describe the dinuclear Mn catalases. 

Catalase (CAT) Therapeutically active protein (detoxification of reactive oxygen species)... 

S Additional information <1> (<1>, POS5 NADH kinase is required for mitochondrial stability with a critical role in detoxification of reactive oxygen species [1]) [1]... 

Figure 20.7. Mechanism of reactive oxygen species generation and detoxification.

Superoxide Reductase (see Iron Proteins with Mononuclear Active Sites). Detoxification of reactive oxygen species in anaerobic microorganisms has recently been shown to center around SOR, a novel mononuclear iron enzyme that reduces superoxide to hydrogen peroxide (see equation 4), rather than dismuting superoxide to oxygen and hydrogen peroxide as is the case for the superoxide dismutases found in aerobic organisms. 

E. Cadenas, Mechanisms of oxygen activation and reactive oxygen species detoxification. In S. Ahmad (ed.). Oxidative Stress and Antioxidant Defenses in Biology. Chapman Hall. New York etc., 1995, pp. 1-61. 

Consequently, in the atherosclerotic aorta accumulation of oxidized LDL and activation of LDL oxidation by C-15 lipoxygenase in the vascular wall in situ may be enhanced, and rate of enzymatic detoxification of reactive oxygen species and lipohydroperoxides in the areas of atheroslerotic lesions may be drastically decreased. All these mechanisms induced the accumulation of lipohydroperoxides in the regions of lipid streaks and fibrous plaques of atherosclerotic aorta [7,8,16] (Figure 8). 

Hossain MA., Piyatida P., da Silva JAT., Fujita M. Molecular mechanism of heavy metal toxicity and tolerance in plants central role of glutathione in detoxification of reactive oxygen species and methylglyoxal and in heavy metal chelation. Journal of Botany 2012 Article ID 872875, 37 pages. 

Tlie ability to respond to oxidative stress is a critical determinant of life-span. Tlie production of oxidants and the scavenging of reactive oxidant species involve cellular strategies for detection and detoxification of reactive oxygen species and are linked to longevity [520] 4 3 jjgjg mutations with links to stress resistance in multicellular organisms... 

Fig. 11 Biochemical pathways for the formation, detoxification, and cellular effects of xenobiotic free radical intermediates and reactive oxygen species (ROS). Fe iron, G-6-P glucose-6-phos-phate, GSH glutathione, GSSG glutathione disulfide, H2O2 hydrogen peroxide, FIO hydroxyl radical, LPO lipoxygenase, NADP nicotinamide adenine dinucleotide phosphate, O2 superoxide, P450 cytochromes P450, PHS prostaglandin H synthase, SOD superoxide dismutase. (Modified from Wells et al. 1997)...

Iron is an essential nutrient supporting the growth and metabolism of marine organisms. Iron-bearing molecules are involved in photosynthetic and respiratory electron transport, nitrate and nitrite reduction, N2 fixation, sulfate reduction, and, as enzyme components, in the detoxification of reactive oxygen species such as O2 and H2O2 [1]. 

Auf dem KeUer, U., Kumin, A., Braun, S., and Wemer, S. Reactive oxygen species and their detoxification in healing skin wounds. [Research Support, Non-U.S. Gov t Review . J. Invest. Dermatol. Svmv Pmc. 2006 11(1) 106-11. 

Adenosine formation is accelerated under hypoxic conditions (Rudolphi et al. 1992), but it is metabohsed only after reperfusion. Now superoxide dismutase and catalase are insufficient to serve detoxification of the reactive oxygen species resulting from the biotransformation of hypoxanthine to xanthine and of xanthine to uric acid. While xanthine oxidase inhibitors as oxypurinol do protect against ischaemic damage (Helfman and Phillis 1989, Lin and Phillis 1992), adenosine deaminase inhibitors as trazodone (Sheid 1985) are expected to reduce the formation of hypoxanthine and xanthine, the substrates for xanthine oxidase. 

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