Purification and characterization of constituent androstenedione 15 alpha-hydroxylase (cytochrome P450(15 alpha AD)) from mouse liver. Sex- and tissue-dependent expression.
Hepatic microsomal androstenedione 15 alpha-hydroxylase (i.e.cytochrome P450(15)alpha AD was purified from female CD-1 mice. Protein purification was monitored in eluates from Fractogel, DEAE-Sephacel, and hydroxylapatite columns at heme absorbing 417 nm, by cytochrome P450 content, reactivity to monoclonal antibody against female-specific rat cytochrome P450 2C12, and androstenedione 15 alpha-hydroxylase activity. The catalytic activity for androgens of the purified cytochrome P450(15)alpha AD, exhibiting a high degree of regioselectivity and stereospecificity, was restricted to the 7 alpha- and 15 alpha-hydroxylation of androstenedione, representing, respectively, > 5% and > 93% of the total metabolites. Polyclonal antibodies against cytochrome P450(15)alpha AD exhibited a concentration-dependent and very selective inhibition of hepatic microsomal androstenedione 7 alpha- and 15 alpha-hydroxylation and a 60% inhibition of benzphetamine demethylation, the latter drug appearing to be a much more effective substrate than androgens. Cytochrome P450(15)alpha AD accounted for about 3% of the total P450 in female mouse liver microsomes. The apparent subunit molecular weight of P450(15)alpha AD was 53,000, and the protein appeared as a single band or sodium dodecyl sulfate-polyacrylamide gels. The isoform was intensely expressed in both liver and lung of CD-1 female mice and was female-predominant in the livers of five or eight strains examined; it was sex-independent in the remaining three strains. Amino-terminal sequence analysis indicates that cytochrome P450(15)alpha AD is a member of the murine cytochrome P450 2c subfamily.
Sharma
M C
MC
Laboratories of Biochemistry, University of Pennsylvania School of Veterinary Medicine, Philadelphia 19104-6048, USA.
Sharma
M R
MR
Jeong
S J
SJ
Shapiro
B H
BH
D000595:Amino Acid Sequence; D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D000072467:Cytochrome P450 Family 2; D005260:Female; D008099:Liver / Q000737:chemistry*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008969:Molecular Sequence Data; D051381:Rats; D013250:Steroid Hydroxylases
D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases; D001189:Aryl Hydrocarbon Hydroxylases; C460223:Cyp2a4 protein, mouse; D000072467:Cytochrome P450 Family 2