Cytochrome c oxidase binding of hydrogen peroxide

Bickar, David; Bonaventura, Joseph; Bonaventura, Celia

doi:10.1021/bi00540a013

Cited by 90 publications

(57 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The peak-to-trough magnitude of the H 2 O 2 -induced difference spectra in the Soret band was typically 30-45 mM Ϫ1 cm Ϫ1 in the WT and in the K channel mutants as compared with ca. 50 mM Ϫ1 cm Ϫ1 observed for beef heart enzyme (29,(42)(43)(44) Before the flash, the sample was incubated for several minutes with 1 mM H2O2 to convert heme a3 to the ferryl-oxo state. After recording a trace (Wildtype), 1 mM potassium cyanide was added and the second trace (ϩKCN) was recorded.…”

Section: Resultsmentioning

confidence: 99%

The roles of the two proton input channels in cytochrome c oxidase from Rhodobacter sphaeroides probed by the effects of site-directed mutations on time-resolved electrogenic intraprotein proton transfer

Konstantinov

Siletsky

Mitchell

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

347

393

View full text Add to dashboard Cite

The crystal structures of cytochrome c oxidase from both bovine and Paracoccus denitrificans reveal two putative proton input channels that connect the heme-copper center, where dioxygen is reduced, to the internal aqueous phase. In this work we have examined the role of these two channels, looking at the effects of site-directed mutations of residues observed in each of the channels of the cytochrome c oxidase from Rhodobacter sphaeroides. A photoelectric technique was used to monitor the time-resolved electrogenic proton transfer steps associated with the photo-induced reduction of the ferryl-oxo form of heme a 3 (Fe 4؉ ‫؍‬ O 2؊ ) to the oxidized form (Fe 3؉ OH ؊ ). This redox step requires the delivery of a ''chemical'' H ؉ to protonate the reduced oxygen atom and is also coupled to proton pumping. It is found that mutations in the K channel (K362M and T359A) have virtually no effect on the ferryl-oxo-to-oxidized (F-to-Ox) transition, although steady-state turnover is severely limited. In contrast, electrogenic proton transfer at this step is strongly

show abstract

Section: Resultsmentioning

confidence: 99%

The roles of the two proton input channels in cytochrome c oxidase from Rhodobacter sphaeroides probed by the effects of site-directed mutations on time-resolved electrogenic intraprotein proton transfer

Konstantinov

Siletsky

Mitchell

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

347

393

View full text Add to dashboard Cite

show abstract

“…Species A then reacts further to yield intermediate P (Compound C, peroxo form), originally assumed to be a peroxo species. This form has also been generated independently from the addition of hydrogen peroxide to oxidized or reduced enzyme (12,140,141), or by the partial reversal of dioxygen chemistry under conditions of high thermodynamic driving force in the reverse direction SCHULTZ CHAN (134,136). It is characterized by an absorption maximum at 607 nm in the optical difference spectrum of the enzyme.…”

Section: Reaction Of the Enzyme With Dioxygenmentioning

confidence: 99%

Structures and Proton-Pumping Strategies of Mitochondrial Respiratory Enzymes

Schultz

Chan

2001

Annu. Rev. Biophys. Biomol. Struct.

248

177

View full text Add to dashboard Cite

Key Words crystal structures, free energy transduction, mitochondrion, redox linkage, respiratory electron transport chain s Abstract Enzymes of the mitochondrial respiratory chain serve as proton pumps, using the energy made available from electron transfer reactions to transport protons across the inner mitochondrial membrane and create an electrochemical gradient used for the production of ATP. The ATP synthase enzyme is reversible and can also serve as a proton pump by coupling ATP hydrolysis to proton translocation. Each of the respiratory enzymes uses a different strategy for performing proton pumping. In this work, the strategies are described and the structural bases for the action of these proteins are discussed in light of recent crystal structures of several respiratory enzymes. The mechanisms and efficiency of proton translocation are also analyzed in terms of the thermodynamics of the substrate transformations catalyzed by these enzymes. CONTENTS

show abstract

“…Orii & King studied the decay process of the "oxygenated oxidase" and found that it decays in two distinct steps (114,115). More recently, Bickar et al, unaware of the earlier work of Okunuki & Orii, reinvestigated the reaction of cytochrome oxidase with H202 (116). They found that resting oxidase binds some H202> whereas the pulsed state (reduced and reoxidized) binds H202 more efficiently and more quickly.…”

Section: The "Peroxy" Intermediatementioning

confidence: 99%