NADPH-generating dehydrogenases: their role in the mechanism of protection against nitro-oxidative stress induced by adverse environmental conditions

Abstract

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NADPH is an essential reductive coenzyme in biosynthetic processes such as cell growth, proliferation and detoxification in eukaryotic cells. It is required by antioxidative systems such as the ascorbate-glutathione cycle and is also necessary for the generation of superoxide radicals by plant NADPH oxidases and for the generation of nitric oxide (NO) by L-arginine-dependent nitric oxide syntase. This coenzyme is principally re-generated by a group of NADP-dehydrogenases enzymes including glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH), both belonging to the pentose phosphate pathway, the NADP-malic enzyme (NADP-ME) and NADP-isocitrate dehydrogenase (NADP-ICDH). In this study, current perspectives on these enzymes in higher plants under different stress situations are reviewed and it is also pointed out that this group of NADPH-generating dehydrogenases is a key element in supporting the mechanism of response to nitro-oxidative stress situations.

Keywords

• Nitric Oxide
• Oxidative Stress
• abiotic stress
• nitrosative stress
• G6PDH
• 6PGDH