Effects of NADH Kinase 3 on the Activities of Some Antioxidant Enzymes in Arabidopsis thaliana under Superoxide Radical Stress

[Objective] To study the effects of NADH kinase 3(NADK3) on the activities of some antioxidant enzymes in A.thaliana under superoxide radical(O2-·) stress.[Method] Effects of NADK3 on changes in the activities of the antioxidant enzymes superoxide dismutase(SOD),catalase(CAT) and peroxidase(POD) in A.thaliana wild type(WT) and nadk3 mutant plants after treatments with O2-·producer methyl viologen(MV) were investigated using the active electrophoresis method.[Result] The activities of the three antioxidant enzymes above in both WT and nadk3 plants under normal growth conditions were low,and SOD and CAT activities in WT were obviously higher than those in nadk3.However,the activities of the three enzymes significantly increased in both WT and the mutant plants after treatments with MV,the increased magnitude of SOD activity in nadk3 was higher than that in WT,and that of CAT activity in nadk3 was lower than that in WT.[Conclusion] NADK3 inhibits the increase of SOD activity and induces the increase of CAT activity under O2-· stress,suggesting that NADK3 is involved in the regulation of the activities of SOD and CAT in A.thaliana under O2-· stress.