SIMPLE AND RAPID PROCEDURE FOR THE PURIFICATION OF PHENOBARBITAL-INDUCIBLE CYTOCHROME-P-450 FROM RAT-LIVER MICROSOMES

被引:177
作者
WEST, SB [1 ]
HUANG, MT [1 ]
MIWA, GT [1 ]
LU, AYH [1 ]
机构
[1] HOFFMANN LA ROCHE INC,DEPT BIOCHEM & DRUG METAB,NUTLEY,NJ 07110
关键词
D O I
10.1016/0003-9861(79)90006-7
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
A rapid and simple procedure has been developed for the purification of a phenobarbital-inducible form of cytochrome P-450 from the liver microsomes of phenobarbitalpretreated rats. Within 2 days approximately 1000-1500 nmol of highly purified cytochrome P-450 with a specific content of 16 nmol/mg protein can be recovered from 4 g of microsomal protein. The procedure consists of solubilization of microsomal protein with sodium cholate, fractionation with polyethylene glycol, and column chromatography at room temperature on DEAE-cellulose. The resulting DEAE-cellulose fraction electrophoreses on polyacrylamide gels in the presence of sodium dodecyl sulfate as a major protein band with a minimum molecular weight of 52,000 and a few faint bands. Further chromatography on QAE Sephadex A-25 essentially removes these faint bands and increases the specific content slightly to 17 nmol/mg protein. Relatively low amounts of this form of cytochrome P-450 appear to be present in microsomes of untreated rats since less than 1% can be recovered as the DEAE-cellulose fraction by this procedure. An identical form is inducible by phenobarbital in rats of different ages and sex. In a reconstituted system under optimal assay conditions, this form of cytochrome P-450 catalyses the N-demethylation of benzphetamine with a turnover number greater than 100 and hydroxylates testosterone at the 16α position but not at the 6β or 7α position. © 1979.
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页码:42 / 50
页数:9
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