Document Detail

Formation of 4-hydroxyochratoxin A from ochratoxin A by rat liver microsomes.
MedLine Citation:
PMID:  7396488     Owner:  NLM     Status:  MEDLINE    
Hydroxyochratoxin A was isolated and identified from the urine of rats after injection with ochratoxin A. By incubating ochratoxin A with rat liver microsomes and reduced nicotinamide adenine dinucleotide phosphate, one major (90%) and two minor metabolites, more polar than ochratoxin A, were formed. Thin-layer chromatography revealed that the major metabolite had Rf values identical to those of hydroxyochratoxin A in six different solvent systems. Formation of the metabolites in vitro was inhibited by carbon monoxide and by metyrapone, and the rate of formation increased after pretreatment of the rats with phenobarbital. A type I spectrum appeared upon binding of ochratoxin A to microsomes with a spectral dissociation constant (Ks) of 37.6 microM. These findings strongly suggest the involvement of a cytochrome P-450 in the hydroxylation of ochratoxin A by rat liver microsomes. Apparent Km and Vmax values for the formation of hydroxyochratoxin A were determined to 50 microM and 5.5 nmol/mg of protein per h, respectively.
F C Størmer; J I Pedersen
Related Documents :
18980268 - Characterization of metabolites of meisoindigo in male and female rat kidney microsomes...
6857728 - Comparative study of rat, dog and human liver microsomal arylamide n-hydroxylases.
11181488 - In vitro biotransformation of xanthohumol, a flavonoid from hops (humulus lupulus), by ...
8968428 - Thymus influences liver functions through hypothalamus-pituitary-gonad axis in rats.
3368038 - Haematological changes induced by the intravenous injection of cck-8 in rats subjected ...
2730158 - The effects of ochratoxin a on postimplantation rat embryos in culture.
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Applied and environmental microbiology     Volume:  39     ISSN:  0099-2240     ISO Abbreviation:  Appl. Environ. Microbiol.     Publication Date:  1980 May 
Date Detail:
Created Date:  1980-09-23     Completed Date:  1980-09-23     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7605801     Medline TA:  Appl Environ Microbiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  971-5     Citation Subset:  IM    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Chromatography, Thin Layer
Cytochrome P-450 Enzyme System / metabolism
Mass Spectrometry
Metabolic Detoxication, Drug
Microsomes, Liver / drug effects,  metabolism*
Ochratoxins / metabolism*,  urine
Phenobarbital / pharmacology
Reg. No./Substance:
0/Ochratoxins; 303-47-9/ochratoxin A; 35299-87-7/4-hydroxyochratoxin A; 50-06-6/Phenobarbital; 9035-51-2/Cytochrome P-450 Enzyme System

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

Previous Document:  Microbial acetyl conjugation of T-2 toxin and its derivatives.
Next Document:  Fermentation of polysaccharides by Klebsielleae and other facultative bacilli.