稀土离子(La^3+)、Ce^(3+)、Nd^(3+))对超氧化物歧化酶活性的影响

Effects of Rare Earth Ions (La^(3+)、Ce^(3+)、Nd^(3+)) on Superoxide Dismutase Activity

利用微量邻苯三酚自氧化法(320 nm)研究了25℃下,0.1 mol/L Tris-HCl缓冲体系中(pH 8.2)不同稀土离子(La3+、Ce3+、Nd3+)对邻苯三酚自氧化和铜锌超氧化物歧化酶(Cu,Zn-SOD)活性的影响,并对可能的抑制作用机理进行了讨论。结果表明,稀土离子La3+、Nd3+对邻苯三酚自氧化有抑制作用,Ce3+对邻苯三酚自氧化表现出先抑制后促进的作用;3种稀土离子对Cu,Zn-SOD酶活性均存在抑制作用,并随稀土离子浓度的增加抑制程度不断增强,而当加入的稀土离子浓度大于2.22×10-5mol/L时,Cu,Zn-SOD完全失活。

The effects of rare earth ions （La3＋,Ce3＋,Nd3＋） on pyrogallol and copper-zinc superoxide dismutase（Cu, Zn-SOD） were studied with the pyrogallol autoxidation method under the condition of 25 ℃, 0.1 mol/L Tris-HC1 buffer solution（pH 8.2）. The possible inhibition mechanism was presumed. The results showed that La3＋,Nd3＋ had an inhibiting action on pyrogal- lol autoxidation. While the rate of pyrogallol autoxidation demonstrated a decreasing trend first, then an increading trend in response to the increasing Ce3＋. Three rare earth ions all could inhibit the activity of Cu,Zn-SOD. And with the increasing of La3＋,Ce3＋,Nd3＋ concentrations, the inhibition degree became strong. When the concentration of rare earth ion was more than 2.22×10-5 molfL, the activity of Cu, Zn-SOD was inhibited absolutely.