Cu^(2+)Cd^(2+)对过氧化氢酶活性的影响及其荧光光谱研究

Effect of Cu^(2+) and Cd^(2+) on Activity and Fluorescence Spectrum of Catalase

分别采用碘量法和荧光光谱法研究了水溶液体系中重金属Cu2+、Cd2+对过氧化氢酶活性的影响。碘量法结果表明,Cu2+、Cd2+对过氧化氢酶既有激活作用也有抑制作用,这种作用与离子的浓度有关,而且在相同的浓度下,Cu2+对过氧化氢酶的作用较Cd2+强。荧光光谱法研究结果表明,Cu2+对过氧化氢酶的荧光有较强的猝灭作用,而Cd2+作用较弱,反映了2种离子对过氧化氢酶活性影响的机理可能不同。从荧光猝灭结果求出Cu2+和过氧化氢酶的结合常数K及结合位点数n,分别为K=18.42L·mol-1,n=0.5。

The influence of Cu2+ and Cd2+ on the activity of catalase was studied by using the method of iodimetry. The relative activity and inhibition rate of Cu2+ and Cd2+ on catalase were calculated. Both Cu2+ and Cd2+ had the action of activiation and inhibition on catalase, which depended on the concentration of Cu2+ and Cd2+ . Moreover, Cu2+ had a stronger effect on catalase than Cd2+ in the same concentration. The effective mechanism was researched using fluorescence spectrum by scanning fluorescence spectrum and determing absorbance. The mechanisms of Cu2+ and Cd2+ affected catalase activity were different. Cu2+ might change the space structure of catalase, but Cd2+ had effect on the catalytic and binding radical. Based on the fluorescence quenching results, the binding constant (K) was 18.42 L· mol- 1 and the number of binding site (n) of catalase with Cu2+ was 0.5.