中国物理B ›› 2002, Vol. 11 ›› Issue (5): 506-508.doi: 10.1088/1009-1963/11/5/318

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    

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

王敖金, 徐建兴   

  1. National Laboratory of Biomacromolecules, Center for Molecular Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
  • 收稿日期:2001-07-11 修回日期:2001-12-28 出版日期:2005-06-13 发布日期:2005-06-13
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No 39900029).

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

Wang Ao-Jin (王敖金), Xu Jian-Xing (徐建兴)   

  1. National Laboratory of Biomacromolecules, Center for Molecular Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2001-07-11 Revised:2001-12-28 Online:2005-06-13 Published:2005-06-13
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No 39900029).

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

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

Key words: switch, electron transfer, cytochrome c oxidase, film

中图分类号:  (Charge (electron, proton) transfer in biological systems)

  • 82.39.Jn
87.14.E- (Proteins)