PMID- 24840065
OWN - NLM
STAT- MEDLINE
DCOM- 20140805
LR  - 20220408
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 53
IP  - 22
DP  - 2014 Jun 10
TI  - How hydrogen peroxide is metabolized by oxidized cytochrome c oxidase.
PG  - 3564-75
LID - 10.1021/bi401078b [doi]
AB  - In the absence of external electron donors, oxidized bovine cytochrome c oxidase 
      (CcO) exhibits the ability to decompose excess H2O2. Depending on the 
      concentration of peroxide, two mechanisms of degradation were identified. At 
      submillimolar peroxide concentrations, decomposition proceeds with virtually no 
      production of superoxide and oxygen. In contrast, in the millimolar H2O2 
      concentration range, CcO generates superoxide from peroxide. At submillimolar 
      concentrations, the decomposition of H2O2 occurs at least at two sites. One is 
      the catalytic heme a3-CuB center where H2O2 is reduced to water. During the 
      interaction of the enzyme with H2O2, this center cycles back to oxidized CcO via 
      the intermediate presence of two oxoferryl states. We show that at pH 8.0 two 
      molecules of H2O2 react with the catalytic center accomplishing one cycle. In 
      addition, the reactions at the heme a3-CuB center generate the surface-exposed 
      lipid-based radical(s) that participates in the decomposition of peroxide. It is 
      also found that the irreversible decline of the catalytic activity of the enzyme 
      treated with submillimolar H2O2 concentrations results specifically from the 
      decrease in the rate of electron transfer from heme a to the heme a3-CuB center 
      during the reductive phase of the catalytic cycle. The rates of electron transfer 
      from ferrocytochrome c to heme a and the kinetics of the oxidation of the fully 
      reduced CcO with O2 were not affected in the peroxide-modified CcO.
FAU - Jancura, Daniel
AU  - Jancura D
AD  - Department of Biophysics, University of P. J. Safarik , Kosice, Slovak Republic.
FAU - Stanicova, Jana
AU  - Stanicova J
FAU - Palmer, Graham
AU  - Palmer G
FAU - Fabian, Marian
AU  - Fabian M
LA  - eng
GR  - GM 080575/GM/NIGMS NIH HHS/United States
GR  - GM 084348/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20140530
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Peroxides)
RN  - BBX060AN9V (Hydrogen Peroxide)
RN  - EC 1.9.3.1 (Electron Transport Complex IV)
SB  - IM
MH  - Animals
MH  - Catalysis
MH  - Cattle
MH  - Electron Transport
MH  - Electron Transport Complex IV/antagonists & inhibitors/chemistry/*metabolism
MH  - Hydrogen Peroxide/chemistry/*metabolism/pharmacology
MH  - Oxidation-Reduction
MH  - Oxidative Stress
MH  - Peroxides/chemistry
PMC - PMC4059527
EDAT- 2014/05/21 06:00
MHDA- 2014/08/06 06:00
PMCR- 2015/05/19
CRDT- 2014/05/21 06:00
PHST- 2014/05/21 06:00 [entrez]
PHST- 2014/05/21 06:00 [pubmed]
PHST- 2014/08/06 06:00 [medline]
PHST- 2015/05/19 00:00 [pmc-release]
AID - 10.1021/bi401078b [doi]
PST - ppublish
SO  - Biochemistry. 2014 Jun 10;53(22):3564-75. doi: 10.1021/bi401078b. Epub 2014 May 
      30.