关键词: 碳纳米管, 直接电化学, 血红蛋白, 辣根过氧化物酶, 葡萄糖氧化酶

Abstract: The redox proteins (enzymes), such as hemoglobin (Hb), horseradish peroxidase (HRP) and glucose oxidase (GOx) were immobilized on the surface of the carbon nanotube modified with glassy carbon (CNT/GC) electrode, respectively. The experimental results showed that the redox proteins (enzymes) underwent effective and stable direct electron transfer reaction at the surface of CNT/GC electrode with a pair of nearly symmetrical redox peaks in phosphate buffer solution. The formal redox potential, E~(0'), is almost independent on the scan rates, the average value of E~(0') for Hb, HRP and GOx is -0.343±0.001, -0.319±0.002 and -0.456±0.001 V (vs.SCE,pH 6.9), respectively. The dependence of E~(0') on the pH of the buffer solution indicates that the direct electron transfer of Hb and HRP is a one-electron-transfer reaction process coupled with one-proton-transfer, while the GOx is a two-electron-transfer reaction process coupled with two-proton-transfer. The experimental results also demonstrated that the immobilized Hb and HRP retained their bioelectrocatalytic activity to the reduction of H_(2)O_(2), and immobilized GOx can catalyze the oxidation of glucose in the presence of ferrocene monocarboxylic acid. The method presented here can be easily extended to immobilize and obtain the direct electrochemistry of other redox enzymes or proteins.