A switch in the electron transfer from heme a to binuclear centre of cytochrome c oxidase

• 来源期刊: 中国物理（英文版）
• 学科: 物理学
• 关键词: switch electron transfer cytochrome c oxidase film
• 年，卷（期）: 2002,（5）
• 页码范围: 506-508
• 页数: 3页
• 分类号: O4
• 语种: 英文

摘要

New experimental evidence that a switch controls the reduction of the heme a3-CuB binuclear centre has beenobserved in the N2-dried thin film of purified cytochrome oxidase. When immersing the enzyme film into the acidphosphate buffer with extremely low concentration of dithionite, a spectrum was given to show a reduction of heme awith no electrons resting on CuA. By increasing dithionite, electrons could be accumulated gradually on CuA, but thebinuclear centre still remains in the oxidized state. When the accumulation of electrons on CuA and/or heme a exceededa threshold, a turnover of reduction of the binuclear centre and oxidation of heme a occurred abruptly. This switch-likeaction is pH-dependent.