Linked Life Data

9602081

Source:http://linkedlifedata.com/resource/pubmed/id/9602081

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1998-6-16
pubmed:abstractText
Artificial cytochrome P450nors (nitric oxide reductase) were prepared by replacing the native protoheme with various 2,4-substituted hemes: meso-, deutero-, and diacetyldeutero-hemes. For these samples, the ratio of low spin/high spin states of the ferric resting enzyme were varied, indicating that the coordination of the water molecule at the iron sixth site was affected by the electron withdrawing capacities of the heme 2,4-substituents. The binding of the water molecule reduces the rate of binding of nitric oxide (NO) to the ferric iron. In addition, the reduction reaction of the ferric-NO complex with NADH, which constitutes the second step in the NO reduction, was facilitated by the electron withdrawing capacity of 2,4-substituents. Consequently, proto- (native-) P450nor exhibited the highest overall enzymatic activity (NO reduction activity), while the enzymes containing diacetyl-, deutero-, and meso-hemes had considerably lower activities, since the NO reduction activity is determined by a balance of the reaction rates of the above two steps. The optical absorption spectra of the ferric-NO and the ferrous-CO complexes of the reconstituted enzymes show that the electron density on the heme in both states was modulated by the substituent groups. However, the resonance Raman spectral measurements showed that the Fe-NO and N-O stretching frequencies in the ferric-NO complex were insensitive to the electron density of the heme while the Fe-CO and C-O stretching frequencies in the ferrous-CO complex were sensitively varied by the electron withdrawing capacity of the 2,4-substituent. The differences are discussed in terms of the difference in the iron-ligand bond characters between the ferric-NO and the ferrous-CO complexes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
23
pubmed:volume
1384
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
103-11
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
The effects of heme modification on reactivity, ligand binding properties and iron-coordination structures of cytochrome P450nor.
pubmed:affiliation
Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
pubmed:publicationType
Journal Article