过氧化氢酶在DNA修饰的热解石墨电极上的直接电子转移(英文)  

Direct Electron Transfer of Catalase at a Pyrolytic Graphite Electrode Modified with DNA

作　　者：荣志江[1] 田燕妮[1] 

机构地区：[1]山西大学分子科学研究所,山西太原030006

出　　处：《山西大学学报（自然科学版）》2005年第4期383-387,共5页Journal of Shanxi University(Natural Science Edition)

基　　金：TheOverseasReturnedScholarFoundationofShanxiProvincein2004

摘　　要：通过将单、双螺旋的小牛胸腺DNA膜修饰在热解石墨电极上,研究了过氧化氢酶的直接伏安和电催化性质.结果表明过氧化氢酶(Cat)-DNA膜上显示出一对很好的几乎可逆的循环伏安峰,在50 mmol·L,pH为7.0磷酸缓冲溶液中,扫描速度为0.1 V·s-1情况下,单、双螺旋DNA膜上,其式电位分别为-0.223 V和-0.209V,其还原和氧化电子传递速率常数值分别为ks,red=21.0 s-1;ks,ox=33.0 s-1和ks,Red=13.5 s-1;ks,ox=13.3 s-1.在pH为3.81～7.72的范围内,Fe(Ⅲ)/Fe(Ⅱ)电对的还原电位随pH呈线性变化,表明一电子的转移伴有一质子的耦合.另外从紫外可见吸收光谱可见,在中性pH条件下,过氧化氢酶在DNA膜中保持了原有的结构不变.此外,我们还研究得到在DNA膜中过氧化氢酶保持了对过氧化氢的催化活性,并提出了可能的催化机制.The direct voltammetry and electrocatalytic properties of catalase （Cat） in single-stranded or doublestranded （ss-or ds-） calf thymus DNA films cast on pyrolytic graphite （PG） electrodes were investigated. CatDNA film electrodes showed a pair of well-defined and nearly reversible cyclic voltammetry peaks. The formal potential （E°′ ） for catalase in a 50 mmol · L^-41 phosphate buffer solution （pH 7.0） at a scan rate of 0.1 V · s^-1 was --0. 209 V with dsDNA and --0. 223 V with ssDNA, respectively. The electron transfer between catalase and PG electrodes was greatly facilitated in the DNA films. At a dsDNA/PG electrode,reduction and oxidation electrontransfer rate constant values of ks, red= 13.5 s^-1 and ks ,ox= 13.3 s^-1 were obtained. At the ssDNA/PG electrode, the values were ks, red = 21. 0 s^-1 and ks, Ox = 33. 0 s^-1, respectively. UV-Vis absorption spectroscopy demonstrated that catalase retained a near native conformation in DNA films at medium pH. We further investigated the responding with pH,Scanrate and HzOz. Obtaining a series valued information.

关 键 词：过氧化氢酶 DNA 直接电化学 电化学催化 

分 类 号：O629[理学—有机化学]