Linked Life Data

3801417

Source:http://linkedlifedata.com/resource/pubmed/id/3801417

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
23
pubmed:dateCreated
1987-3-16
pubmed:abstractText
A kinetic model is presented from which steady-state equations are derived that describe the intramolecular competition for the enzymatically mediated hydroxylation of two like groupings of a prochiral substrate. The observed isotope effect in such a system if one of the groupings is isotopically labeled is shown to be a function of three parameters: the equilibrium constant for the catalytically sensitive orientations of the two prochiral groupings at the active site, the intrinsic isotope effect associated with the bond-breaking step, and the relative rates of bond breaking vs. enzyme-substrate dissociation. The expected isotope effects associated with the omega-hydroxylation of racemic, (R)-, and (S)-2-phenylpropane-1,1,1-d3 and the product stereoselectivity associated with the omega-hydroxylation of (R)- and (S)-[1-13C]-2-phenylpropane were determined with microsomal preparations (cytochrome P-450) from untreated and phenobarbital- and beta-naphthoflavone-pretreated male Sprague-Dawley rats. The data from these experiments allow the observed isotope effect to be evaluated in terms of its component parts, i.e., expected isotope effects, product stereoselectivity, and equilibrium constant. These data further suggest that the intramolecular isotope effect is consistent with a hydrogen abstraction recombination mechanism and is largely dependent upon the chemical nature of the porphyrin-Fe-oxene complex but independent of specific apoprotein structure, product stereoselectivity is primarily dependent upon apoprotein structure, and product stereoselectivity is a good measure of the equilibrium constant and both parameters are dependent upon the chirality of the active site.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
25
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7336-43
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1986
pubmed:articleTitle
Prochiral selectivity and intramolecular isotope effects in the cytochrome P-450 catalyzed omega-hydroxylation of cumene.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.