Linked Life Data

17644182

Source:http://linkedlifedata.com/resource/pubmed/id/17644182

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2007-9-10
pubmed:abstractText
The heme oxygenase (HO) reaction consists of three successive oxygenation reactions, i.e. heme to alpha-hydroxyheme, alpha-hydroxyheme to verdoheme, and verdoheme to biliverdin-iron chelate. Of these, the least understood step is the conversion of verdoheme to biliverdin-iron chelate. For the cleavage of the oxaporphyrin ring of ferrous verdoheme, involvement of a verdoheme pi-neutral radical has been proposed. To probe this hypothetical mechanism in the HO reaction, we performed electrochemical reduction of ferrous verdoheme complexed with rat HO-1 under anaerobic conditions. On the basis of the electrochemical spectral changes, the midpoint potential for the one-electron reduction of the oxaporphyrin ring of ferrous verdoheme was found to be -0.47+/-0.01 V vs the normal hydrogen electrode (NHE). Because this potential is far lower than those of both flavins of NADPH-cytochrome P450 reductase, and of NADPH, it is concluded that the one-electron reduction of the oxaporphyrin ring of ferrous verdoheme is unlikely to occur and that the formation of the pi-neutral radical cannot be the initial step in the degradation of verdoheme by HO. Rather, it appears more reasonable to consider an alternative mechanism in which binding of O(2) to the ferrous iron of verdoheme is the first step in the degradation of verdoheme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0162-0134
pubmed:author
pubmed:issnType
Print
pubmed:volume
101
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1394-9
pubmed:dateRevised
2011-9-26
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Electrochemical reduction of ferrous alpha-verdoheme in complex with heme oxygenase-1.
pubmed:affiliation
Department of Medical Biochemistry, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural