Purification and characterization of the major microsomal cytochrome P-450 form induced by trans-stilbene oxide in rat liver.
The major form of microsomal cytochrome P-450 induced by trans-stilbene oxide in the liver of male Sprague-Dawley rats was purified and characterized, and compared with the isolated cytochrome P-450 B2 forms from phenobarbital- and 3-methylcholanthrene-pretreated animals. The apparent subunit molecular weight of the trans-stilbene oxide-induced cytochrome was found to be 53 000 using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the absorbance maximum of the carbon monoxide complex of the ferrous cytochrome was 450 nm. Reconstitution of the N-demethylase activity towards three different substrates showed high and similar activities with the cytochrome P-450 B2 forms from trans-stilbene oxide or phenobarbital-treated rats, with one exception. Amino-acid analysis also showed a very high degree of similarity between these two forms. Upon proteinase treatment with three different proteinases the trans-stilbene oxide-induced cytochrome demonstrated in each case a peptide pattern identical to that obtained with the phenobarbital-induced B2 form. Furthermore, both forms are completely immunologically cross-reactive. We therefore conclude from these experiments that the liver microsomal P-450 B2 from trans-stilbene oxide and phenobarbital-treated rats are very closely related, if not identical.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis* / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction; D005779:Immunodiffusion; D007527:Isoenzymes / Q000096:biosynthesis / Q000302:isolation & purification*; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D008970:Molecular Weight; D010634:Phenobarbital / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013267:Stilbenes / Q000494:pharmacology*
D000596:Amino Acids; D007527:Isoenzymes; D013267:Stilbenes; D008748:Methylcholanthrene; D003577:Cytochrome P-450 Enzyme System; C025906:stilbene oxide; D010634:Phenobarbital