Linked Life Data

9425077

Source:http://linkedlifedata.com/resource/pubmed/id/9425077

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1998-2-13
pubmed:abstractText
We here report EPR studies that provide evidence for radical intermediates generated from the glycyl radical of activated pyruvate formate-lyase (PFL) during the process of oxygen-dependent enzyme inactivation, radical quenching, and protein fragmentation. Upon exposure of active PFL to air, a long-lived radical intermediate was generated, which exhibits an EPR spectrum assigned to a sulfinyl radical (RSO*). The EPR spectrum of a sulfinyl radical was also generated from the activated C418A mutant of PFL, indicating that Cys 418 is not the site of sulfinyl radical formation. Exposure of the activated C419A mutant or C418AC419A double mutant to air on the other hand, resulted in a new EPR spectrum that we assign to the alpha-carbon peroxyl radical (ROO*) of the active-site glycine, G734. These findings suggest that C419 is the site of sulfinyl radical formation and that replacement of this cysteine with alanine results in the accumulation of the carbon peroxyl radical. The results also support the proposal that the peroxyl radical and the sulfinyl radical are intermediates in the oxygen-dependent inactivation and cleavage of the protein. Moreover, these observations are consistent with the hypothesis that C419 and G734 are in close proximity in the activated enzyme and may participate in a glycyl/thiyl radical equilibrium. A mechanism that accounts for the formation of the radical intermediates is proposed.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
13
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
558-63
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Dioxygen inactivation of pyruvate formate-lyase: EPR evidence for the formation of protein-based sulfinyl and peroxyl radicals.
pubmed:affiliation
Department of Biochemistry, Merck Research Laboratories, Rahway, New Jersey 07065-0900, USA.
pubmed:publicationType
Journal Article