钙离子对HRPC结构和电催化活性影响的研究

Effect of Calcium Ion on Structure and Electrocatalysis of Horseradish Peroxidase Isoenzyme C

通过比较辣根过氧化物酶同工酶C(HRPC)中Ca2+移除前后的HRPC的光谱和电化学特性,阐明了Ca2+的存在对HRPC的重要作用。移除Ca2+后HRPC的紫外-可见吸收光谱发生了变化,Soret带的最大特征吸收峰以及α带和β带特征吸收峰均发生不同程度的蓝移和峰强减弱,表明其血红素微环境及结构发生了变化。移除Ca2+后的HRPC也可在与聚L型赖氨酸共修饰的石墨电极上表现出对H2O2的催化响应,但是天然HRPC比去除Ca2+后的HRPC对H2O2表现出更低的检测限,更宽的检测范围,更高的灵敏度以及更好的稳定性。实验结果表明,Ca2+对HRPC血红素微环境的保持、催化活性和稳定性均有重要的作用。

Effect of Ca^2＋ on the structural and electrocatalytic properties of horseradish peroxidase isoenzyme C（HRPC） was investigated.UV-Vis absorption spectra of HRPC are found to be changed after removal of calcium.The absorption peaks of Soret region and α,β band are all blue-shifted and decreased,which indicates that the heme microenvironment and structure of HRPC can be changed due to calcium removal.Calcium-depleted HRPC is also able to catalyze the reduction of H2O2,however,native HRPC has lower detection limit,wider detection range,higher sensitivity to H2O2,as well as better stability.These results indicate that Ca^2＋ plays critical role in maintaining the heme microenvironment,catalytic activity and stability of HRPC.