Linked Life Data

1312347

Source:http://linkedlifedata.com/resource/pubmed/id/1312347

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1992-4-22
pubmed:abstractText
The reaction of dioxygen with the ferrous forms of the cloned cytochrome c peroxidase [CCP(MI)] and mutants of CCP(MI) prepared by site-directed mutagenesis was studied by photolysis of the respective ferrous-CO complexes in the presence of dioxygen. Reaction of ferrous CCP(MI) with dioxygen transiently formed a FeII-O2 complex (bimolecular rate constant = (3.8 +/- 0.3) x 10(4) M-1 s-1 at pH 6.0; 23 degrees C) that reacted further (first-order rate constant = 4 +/- 1 s-1) to form a product with an absorption spectrum and an EPR radical signal at g = 2.00 that were identical to those of compound I formed by the reaction of CCP(MI)III with peroxide. Thus, the product of the reaction of CCP(MI)II with dioxygen retained three of the four oxidizing equivalents of dioxygen. Gel electrophoresis of the CCP(MI)II + dioxygen reaction products showed that covalent dimeric and trimeric forms of CCP(MI) were produced by the reaction of CCP(MI)II with dioxygen. Photolysis of the CCP(MI)II-CO complex in the presence of ferrous cytochrome c prevented the appearance of the cross-linked forms and resulted in the oxidation of 3 mol of cytochrome c/mol of CCP(MI)II-CO added. The results provide evidence that reaction of CCP(MI)II with dioxygen causes transient oxidation of the enzyme by 1 equiv above the normal compound I oxidation state. Mutations that eliminate the broad EPR signal at g = 2.00 characteristic of the compound I radical also prevented the rapid oxidation of the ferrous enzyme by dioxygen.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
31
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2789-97
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Reaction of ferrous cytochrome c peroxidase with dioxygen: site-directed mutagenesis provides evidence for rapid reduction of dioxygen by intramolecular electron transfer from the compound I radical site.
pubmed:affiliation
Department of Chemistry, University of California, San Diego, La Jolla 92093.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.