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Predicate | Object |
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rdf:type | |
lifeskim:mentions |
umls-concept:C0010762,
umls-concept:C0017262,
umls-concept:C0020364,
umls-concept:C0022173,
umls-concept:C0025519,
umls-concept:C0034493,
umls-concept:C0127400,
umls-concept:C0185117,
umls-concept:C0441655,
umls-concept:C1280500,
umls-concept:C1710236,
umls-concept:C1979928,
umls-concept:C2709248,
umls-concept:C2911684
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pubmed:issue |
1
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pubmed:dateCreated |
1986-5-12
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pubmed:abstractText |
The content of cytochrome P-450, isozyme 6, in the rabbit pulmonary microsomal fraction was estimated by immunochemical methods to be 1 to 3% of the total cytochrome P-450. Following treatment of rabbits with 2,3,7,8-tetrachlorodibenzo-p-dioxin, the pulmonary microsomal concentration of isozyme 6 increased 16-fold. Isozyme 6 was also detected by immunochemical methods, but not by electrophoresis and staining for protein, in preparations of isozyme 5 isolated from the pulmonary microsomal fraction of untreated rabbits. The metabolism of benzo[a]pyrene in these preparations was found to be catalyzed by isozyme 6, not by isozyme 5 as previously concluded. Cytochrome P-450, isozyme 4, was not detected in the pulmonary microsomal fraction from untreated or 2,3,7,8-tetrachlorodibenzo-p-dioxin-treated rabbits. Although benzo[a]pyrene and 7-ethoxyresorufin are both substrates for isozyme 6, the pulmonary microsomal metabolism of these compounds was not increased to the same extent by treatment of rabbits with 2,3,7,8-tetrachlorodibenzo-p-dioxin (about 13-fold for 7-ethoxyresorufin and less than 2-fold for BP). However, lack of agreement between increases in isozyme 6 content and activity, and between the relative increases of the activities with the two substrates, was overcome by the addition of purified NADPH-cytochrome P-450 reductase to the microsomal incubations. When alpha-naphthoflavone, at the minimum concentration required for greater than 90% inhibition of isozyme 6 catalysis, was present in the incubations, no increases in activity were obtained by the addition of purified reductase. The turnover numbers of isozyme 6 in microsomal preparations incubated with purified reductase were similar to those of the purified isozyme in a reconstituted monooxygenase system. The relevance of our results to determinations of the substrate specificities and the microsomal concentrations and activities of isozymes of cytochrome P-450 is discussed. In addition, these parameters are used to assess the extent to which the catalytic potential of isozyme 6 is expressed in the rabbit pulmonary microsomal fraction.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Benzo(a)pyrene,
http://linkedlifedata.com/resource/pubmed/chemical/Benzoflavones,
http://linkedlifedata.com/resource/pubmed/chemical/Cytochrome P-450 Enzyme System,
http://linkedlifedata.com/resource/pubmed/chemical/Isoenzymes,
http://linkedlifedata.com/resource/pubmed/chemical/Oxazines,
http://linkedlifedata.com/resource/pubmed/chemical/Oxygenases,
http://linkedlifedata.com/resource/pubmed/chemical/Tetrachlorodibenzodioxin,
http://linkedlifedata.com/resource/pubmed/chemical/alpha-naphthoflavone,
http://linkedlifedata.com/resource/pubmed/chemical/ethoxyresorufin
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pubmed:status |
MEDLINE
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pubmed:month |
Apr
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pubmed:issn |
0003-9861
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
246
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
128-42
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pubmed:dateRevised |
2005-11-17
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pubmed:meshHeading |
pubmed-meshheading:3963817-Animals,
pubmed-meshheading:3963817-Benzo(a)pyrene,
pubmed-meshheading:3963817-Benzoflavones,
pubmed-meshheading:3963817-Catalysis,
pubmed-meshheading:3963817-Chromatography, DEAE-Cellulose,
pubmed-meshheading:3963817-Cytochrome P-450 Enzyme System,
pubmed-meshheading:3963817-Electrophoresis, Polyacrylamide Gel,
pubmed-meshheading:3963817-Enzyme Activation,
pubmed-meshheading:3963817-Isoenzymes,
pubmed-meshheading:3963817-Lung,
pubmed-meshheading:3963817-Male,
pubmed-meshheading:3963817-Microsomes,
pubmed-meshheading:3963817-Microsomes, Liver,
pubmed-meshheading:3963817-Oxazines,
pubmed-meshheading:3963817-Oxygenases,
pubmed-meshheading:3963817-Rabbits,
pubmed-meshheading:3963817-Tetrachlorodibenzodioxin
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pubmed:year |
1986
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pubmed:articleTitle |
The effect of substrate on the expression of activity catalyzed by cytochrome P-450: metabolism mediated by rabbit isozyme 6 in pulmonary microsomal and reconstituted monooxygenase systems.
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pubmed:publicationType |
Journal Article
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