用电子顺磁共振EPR技术研究铜锌超氧化物歧化酶(Cu·Zn-SOD)与底物(O_2~(·-)反应达到平衡态时铜离子的EPR波谱表明,在平衡态时的铜离子处于还原态。用还原剂H_2O_2、NaBH_4处理Cu·Zn-SOD后,酶活力变化不同,电泳行为也不同。用NaBH_4处理SOD其活性及电泳行为接近天然酶,但经H_2O_2还原后的酶活性损失严重,电泳后出现多条色带。

A study on the mechanism of action of SOD is carried out by electron parmagnetic resonance (EPR) . At the equilibrium state, copper ion in the SOD molecule shows 50% of Cu2+ and 50% Cu+ respectively. This indicates that the rate of catalytic reduction and oxidation of copper ion are equal. EPR is also used to measure the oxidation state of copper ion in Cu.Zn-SOD treated by reductants such as NaBH4 and H2O2, and the activity and electrophoretic patterns are also studied. The Cu2 + in Cu.Zn-SOD is reduced either by NaBH4 or byH2O2. The electrophoretic behavior and activity of the NaBH4 reduced SOD are similar to that of the native SOD, in contrast, the electrophoretic behavior of the enzyme treated with H2O2 shows an intensive band with higher electrophoretic mobility than that of the native enzyme, and the reduced enzyme has almost completely lost its activity.