Linked Life Data

11451445

Source:http://linkedlifedata.com/resource/pubmed/id/11451445

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2001-7-13
pubmed:abstractText
Eosinophil peroxidase, the major granule protein in eosinophils, is the least studied human peroxidase. Here, we have performed spectral and kinetic measurements to study the nature of eosinophil peroxidase intermediates, compounds I and II, and their reduction by the endogenous one-electron donors ascorbate and tyrosine using the sequential-mixing stopped-flow technique. We demonstrate that the peroxidase cycle of eosinophil peroxidase involves a ferryl/porphyrin radical compound I and a ferryl compound II. In the absence of electron donors, compound I is shown to be transformed to a species with a compound II-like spectrum. In the presence of ascorbate or tyrosine compound I is reduced to compound II with a second-order rate constant of (1.0+/-0.2)x10(6) M(-1) s(-1) and (3.5+/-0.2)x10(5) M(-1) s(-1), respectively (pH 7.0, 15 degrees C). Compound II is then reduced by ascorbate and tyrosine to native enzyme with a second-order rate constant of (6.7+/-0.06)x10(3) M(-1) s(-1) and (2.7+/-0.06)x10(4) M(-1) s(-1), respectively. This study revealed that eosinophil peroxidase compounds I and II are able to react with tyrosine and ascorbate via one-electron oxidations and therefore generate monodehydroascorbate and tyrosyl radicals. The relatively fast rates of the compound I reduction demonstrate that these reactions may take place in vivo and are physiologically relevant.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
1548
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
121-8
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Spectral and kinetic studies on eosinophil peroxidase compounds I and II and their reaction with ascorbate and tyrosine.
pubmed:affiliation
Institute of Chemistry, University of Agricultural Sciences, Muthgasse 18, A-1190 Vienna, Austria.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't