Linked Life Data

2122607

Source:http://linkedlifedata.com/resource/pubmed/id/2122607

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
9
pubmed:dateCreated
1990-12-12
pubmed:abstractText
1. The role of cytochrome P-450 in the one-electron reduction of mitomycin c was studied in rat hepatic microsomal systems and in reconstituted systems of purified cytochrome P-450. Formation of H2O2 from redox cycling of the reduced mitomycin c in the presence of O2 and the alkylation of p-nitrobenzylpyridine (NBP) in the absence of O2 were taken as parameters. 2. With liver microsomes from both 3-methylcholanthrene (MC)- and phenobarbital (PB)-pretreated rats, reverse type I difference spectra were observed, indicative of a weak interaction between mitomycin c and the substrate binding site of cytochrome P-450. Mitomycin c inhibited the oxidative dealkylation of aminopyrine and ethoxyresorufin in both microsomal systems. 3. Under aerobic conditions the H2O2 production in the microsomal systems was dependent on NADPH, O2 and mitomycin c, and was inhibited by the cytochrome P-450 inhibitors, metyrapone and SKF-525A. 4. Although purified NADPH-cytochrome P-450 reductase was also effective in reduction of mitomycin c and the concomitant reduction of O2, complete microsomal systems and fully reconstituted systems of cytochrome P-450b or P-450c and the reductase were much more efficient. 5. Under anaerobic conditions in the microsomal systems both reduction of mitomycin c (measured as the rate of substrate disappearance) and the reductive alkylation of NBP were dependent on cytochrome P-450. 6. The relative rate of reduction of mitomycin c by purified NADPH-cytochrome P-450 reductase was lower than that by a complete microsomal system containing both cytochrome P-450 and a similar amount of NADPH-cytochrome P-450 reductase. 7. It is concluded that although NADPH-cytochrome P-450 reductase is active in the one-electron reduction of mitomycin c, the actual metabolic locus for the reduction of this compound in liver microsomes under a relatively low O2 tension is more likely the haem site of cytochrome P-450.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0049-8254
pubmed:author
pubmed:issnType
Print
pubmed:volume
20
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
967-78
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:2122607-Aerobiosis, pubmed-meshheading:2122607-Alkylating Agents, pubmed-meshheading:2122607-Alkylation, pubmed-meshheading:2122607-Anaerobiosis, pubmed-meshheading:2122607-Animals, pubmed-meshheading:2122607-Cytochrome P-450 Enzyme System, pubmed-meshheading:2122607-Electron Transport, pubmed-meshheading:2122607-Glucose Oxidase, pubmed-meshheading:2122607-Hydrogen Peroxide, pubmed-meshheading:2122607-Kinetics, pubmed-meshheading:2122607-Liver, pubmed-meshheading:2122607-Male, pubmed-meshheading:2122607-Methylcholanthrene, pubmed-meshheading:2122607-Microsomes, Liver, pubmed-meshheading:2122607-Mitomycin, pubmed-meshheading:2122607-Mitomycins, pubmed-meshheading:2122607-NADPH-Ferrihemoprotein Reductase, pubmed-meshheading:2122607-Oxidation-Reduction, pubmed-meshheading:2122607-Phenobarbital, pubmed-meshheading:2122607-Rats, pubmed-meshheading:2122607-Rats, Inbred Strains
pubmed:year
1990
pubmed:articleTitle
One-electron reduction of mitomycin c by rat liver: role of cytochrome P-450 and NADPH-cytochrome P-450 reductase.
pubmed:affiliation
Department of Pharmacochemistry (Molecular Toxicology), Free University, Amsterdam, The Netherlands.
pubmed:publicationType
Journal Article, In Vitro