Cytochrome c oxidase

Decay of the primary oxygen intermediate involves direct electron transfer from cytochrome a

Sanghwa Han, Yuan Chin Ching, Denis L. Rousseau

Research output: Contribution to journalArticle

75 Citations (Scopus)

Abstract

The decay of the primary intermediate generated in the reaction of oxygen with cytochrome c oxidase is nearly one order of magnitude faster in the fully reduced form of the enzyme than it is in the mixed valence form. To account for this observation, we propose a model describing the early molecular events in the reaction. In this model the decay of the primary Fe-O2 intermediate in the fully reduced enzyme is a consequence of direct electron transfer from cytochrome a. To test the model we measured the time dependence of the oxidation of cytochrome a by monitoring the resonance Raman scattering intensity of its vibrational modes. A rapid oxidation of cytochrome a was detected that quantitatively agrees with the model. These results indicate that the mechanism of oxygen reduction and proposed frameworks for proton translocation must be reexamined.

Original languageEnglish (US)
Pages (from-to)8408-8412
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume87
Issue number21
StatePublished - 1990
Externally publishedYes

Fingerprint

Cytochromes a
Electron Transport Complex IV
Electrons
Oxygen
Raman Spectrum Analysis
Enzymes
Protons

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

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title = "Cytochrome c oxidase: Decay of the primary oxygen intermediate involves direct electron transfer from cytochrome a",
abstract = "The decay of the primary intermediate generated in the reaction of oxygen with cytochrome c oxidase is nearly one order of magnitude faster in the fully reduced form of the enzyme than it is in the mixed valence form. To account for this observation, we propose a model describing the early molecular events in the reaction. In this model the decay of the primary Fe-O2 intermediate in the fully reduced enzyme is a consequence of direct electron transfer from cytochrome a. To test the model we measured the time dependence of the oxidation of cytochrome a by monitoring the resonance Raman scattering intensity of its vibrational modes. A rapid oxidation of cytochrome a was detected that quantitatively agrees with the model. These results indicate that the mechanism of oxygen reduction and proposed frameworks for proton translocation must be reexamined.",
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TY - JOUR

T1 - Cytochrome c oxidase

T2 - Decay of the primary oxygen intermediate involves direct electron transfer from cytochrome a

AU - Han, Sanghwa

AU - Ching, Yuan Chin

AU - Rousseau, Denis L.

PY - 1990

Y1 - 1990

N2 - The decay of the primary intermediate generated in the reaction of oxygen with cytochrome c oxidase is nearly one order of magnitude faster in the fully reduced form of the enzyme than it is in the mixed valence form. To account for this observation, we propose a model describing the early molecular events in the reaction. In this model the decay of the primary Fe-O2 intermediate in the fully reduced enzyme is a consequence of direct electron transfer from cytochrome a. To test the model we measured the time dependence of the oxidation of cytochrome a by monitoring the resonance Raman scattering intensity of its vibrational modes. A rapid oxidation of cytochrome a was detected that quantitatively agrees with the model. These results indicate that the mechanism of oxygen reduction and proposed frameworks for proton translocation must be reexamined.

AB - The decay of the primary intermediate generated in the reaction of oxygen with cytochrome c oxidase is nearly one order of magnitude faster in the fully reduced form of the enzyme than it is in the mixed valence form. To account for this observation, we propose a model describing the early molecular events in the reaction. In this model the decay of the primary Fe-O2 intermediate in the fully reduced enzyme is a consequence of direct electron transfer from cytochrome a. To test the model we measured the time dependence of the oxidation of cytochrome a by monitoring the resonance Raman scattering intensity of its vibrational modes. A rapid oxidation of cytochrome a was detected that quantitatively agrees with the model. These results indicate that the mechanism of oxygen reduction and proposed frameworks for proton translocation must be reexamined.

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M3 - Article

VL - 87

SP - 8408

EP - 8412

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 21

ER -