| Oxidative processes during senescence involve an increase in enzyme activities generating oxygen radicals and superoxide ions. |
| Xanthine oxidase, a flavoprotein, catalyses the oxidation of hypoxanthine to xanthine and then generated superoxide and uric acid. |
| Also, nitric oxide synthase will produce superoxide in lieu of nitric oxide when arginine concentration is low. |
| It functions to prevent the formation of superoxide radicals and detoxify a variety of foreign compounds. |
| These included transcripts for an ascorbate peroxidase and two superoxide dismutases. |
| Paraquat acts as an alternative electron acceptor from PSI generating superoxide. |
