Linked Life Data

11327850

Source:http://linkedlifedata.com/resource/pubmed/id/11327850

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2001-4-30
pubmed:abstractText
In the absence of any external electron donor, the "peroxy" intermediate of cytochrome c oxidase (CcO-607) is converted to the ferryl form (CcO-580) and subsequently to oxidized enzyme. The rate of conversion of CcO-607 to the CcO-580 form is pH dependent between pH 3.0 and pH 7.6. A plot of the logarithm of the rate constant for this conversion is a linear function of pH with a slope of -0.92, implying the involvement of a single proton in the transition. Upon rapidly lowering the pH from 8.1 to 5.8, the uptake of one proton was observed by direct pH measurement, and the kinetics of proton uptake coincide with the spectral conversion of CcO-607 to CcO-580. We interpret the slow endogenous decay of CcO-607 to CcO-580 to be the result of proton transfer to a deprotonated group generated in the binuclear cavity during CcO-607 formation. This group is not freely accessible to protons from the medium, and its pK(a) is probably higher than 9.0.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1867-74
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Proton involvement in the transition from the "peroxy" to the ferryl intermediate of cytochrome c oxidase.
pubmed:affiliation
Department of Biochemistry and Cell Biology, MS 140, Rice University, 6100 Main, Houston, TX 77005-1892, USA. fabian@bioc.rice.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't