Linked Life Data

3128014

Source:http://linkedlifedata.com/resource/pubmed/id/3128014

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1988-4-22
pubmed:abstractText
1. Phenacetin O-deethylation catalysed by human liver microcomes has been examined over a substrate concentration range of 2.5 to 700 microM using preparations of eight human liver samples. Michaelis-Menten kinetics described phenacetin oxidation satisfactorily in five of these samples; apparent Km values were in the range of 17.7 to 38.4 microM. 2. In the three other livers a single rectangular hyperbolic relationship did not describe the substrate saturation data adequately; analyses in these three cases requiring two classes of catalytic site. The apparent Km value for the higher affinity class of site in these three samples was within the range quoted above, but limitations imposed by assay sensitivity and phenacetin solubility obviated accurate characterization of the lower affinity class. 3. Estimates of Vmax for the high affinity class of site in the eight livers varied eleven-fold and there was no correlation between either Km or Vmax and microsomal cytochrome P-450 specific content, NADPH cytochrome c (P-450) reductase specific activity or ethylmorphine demethylase activity. 4. Propranolol was a potent competitive inhibitor of phenacetin deethylation with apparent Ki values of 2 to 7 microM describing its effect on the higher affinity class of activity. Propranolol was also an inhibitor of the lower affinity phenacetin deethylase identified in three of the livers, however the mechanism of inhibition could not be characterized. 5. These data suggest the possibility that propranolol oxidation may be mediated in part, by one or more human liver cytochrome P-450 species catalyzing phenacetin oxidation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0049-8254
pubmed:author
pubmed:issnType
Print
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
95-104
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1988
pubmed:articleTitle
Phenacetin O-deethylation by human liver microsomes: kinetics and propranolol inhibition.
pubmed:affiliation
Department of Biochemistry, University of Queensland, St. Lucia, Australia.
pubmed:publicationType
Journal Article