Linked Life Data

6619132

Source:http://linkedlifedata.com/resource/pubmed/id/6619132

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
19
pubmed:dateCreated
1983-11-23
pubmed:abstractText
In the presence of peroxyphenylacetic acid and a hydroxylatable substrate, cytochrome P-450LM2 catalyzes two reactions which proceed concurrently, decarboxylation of the peroxyacid and hydroxylation of substrate. While the first process is definitely the result of homolytic cleavage of the peroxide O--O bond, the second may involve a different mechanistic pathway. We have undertaken to determine the relationship between these two processes through a kinetic analysis of the system. Seven different mechanistic schemes are advanced to account for the two processes. The two reactions were found to have different apparent Michaelis constants for peroxyacid and different inhibition constants for cyanide. Since the ratio of the two products is saturable at high substrate concentrations, the decarboxylation reaction can proceed from both substrate-bound and substrate-free enzyme. By appropriate manipulation of the rate equations it is possible to derive expressions for the ratio of hydrogen abstraction rate constants for a series of p-substituted toluene substrates compared to toluene. The nature of the correlation of these expressions with delta in a Hammett plot allowed some of the schemes to be eliminated. After consideration of all the data, we concluded that the processes of decarboxylation and hydroxylation occur in separate pathways and do not involve any common intermediate beyond the ferric resting state of the enzyme.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11610-6
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Competing modes of peroxyacid flux through cytochrome P-450.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't