Document Detail


Role of cytochrome P-450 and flavin-containing monooxygenase in the N-hydroxylation of N-methyl-4-aminoazobenzene in rat liver: analysis with purified enzymes and antibodies.
MedLine Citation:
PMID:  6510637     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
By means of high pressure liquid chromatography, the role of flavin-containing monooxygenase (FMO) and cytochrome P-450 (cyt. P-450) in the metabolism of N-methyl-4-aminoazobenzene (MAB) by rat liver microsomes in vitro was studied with the help of antibodies and a chemical inhibitor. Antibody against cyt. P-488 from 3-methylcholanthrene-treated rats (MC-P-448) decreased the formation of N-hydroxy-N-methyl-4-aminoazobenzene (N-OH-MAB) by about 30% in microsomes from MC-treated rats (MC-microsomes), but showed no inhibitory effect on the formation of N-OH-MAB in microsomes from untreated rats (untreated microsomes) or in microsomes from phenobarbital-treated rats (PB-microsomes). Antibody against cyt. P-450 from PB-treated rats did not inhibit N-hydroxylation of MAB by any of the microsomes tested. A competitive inhibitor of FMO, methimazole, inhibited the N-hydroxylation of MAB by 65% in the case of MC-microsomes, and the residual activity was inhibited completely by anti-NADPH-cytochrome P-450 reductase (anti-fPT) antibody. These results indicate that in MC-microsomes, the N-hydroxylation of MAB is catalyzed by both FMO and MC-P-448, but in untreated and PB-microsomes the reaction is catalyzed exclusively by FMO.
Authors:
T Kimura; M Kodama; C Nagata
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Gann = Gan     Volume:  75     ISSN:  0016-450X     ISO Abbreviation:  Gann     Publication Date:  1984 Oct 
Date Detail:
Created Date:  1985-02-04     Completed Date:  1985-02-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8214471     Medline TA:  Gann     Country:  JAPAN    
Other Details:
Languages:  eng     Pagination:  895-904     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Antigen-Antibody Complex
Aryl Hydrocarbon Hydroxylases / metabolism*
Azo Compounds / metabolism*
Biotransformation
Carbon Radioisotopes
Carcinogens / metabolism*
Cytochrome P-450 Enzyme System / metabolism*
Hydroxylation
Immune Sera
Kinetics
Male
Methylcholanthrene / pharmacology
Microsomes, Liver / drug effects,  enzymology*
Rats
Rats, Inbred Strains
p-Aminoazobenzene / analogs & derivatives,  metabolism*
Chemical
Reg. No./Substance:
0/Antigen-Antibody Complex; 0/Azo Compounds; 0/Carbon Radioisotopes; 0/Carcinogens; 0/Immune Sera; 56-49-5/Methylcholanthrene; 60-09-3/p-Aminoazobenzene; 621-90-9/N-methyl-4-aminoazobenzene; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.14.14.1/Aryl Hydrocarbon Hydroxylases

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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