Characterization of catalytic properties and expression of cytochrome P-450(14DM), lanosterol 14 alpha-demethylase, in rats.
Cytochrome P-450(14DM) catalyzing lanosterol 14 alpha-demethylation was purified from rat liver and was characterized by its catalytic properties and mode of expression. The purified protein, with an apparent molecular mass of 51 kDa, showed 24,25-dihydrolanosterol 14 alpha-demethylation activity (3.05 nmol/min/mg protein) in a reconstituted system with an apparent Km value of 40 microM. The reconstituted enzyme converted 32-hydroxy-24,25-dihydrolanosterol and 32-oxo-24,25-dihydrolanosterol (the oxygenated intermediates of 24,25-dihydrolanosterol) to 4,4-dimethylcholesta-8,14-dien-3 beta-ol (the 32-nor compound). Immunoblot analysis of liver microsomes from male and female rats showed that the enzyme protein was expressed at an early stage of development and attained its maximum at 4 weeks after birth, retaining the same level thereafter. No difference was evident between males and females in the level of cytochrome P-450(14DM) in the liver up to 7 weeks after birth.
Endo
M
M
Kyoritsu College of Pharmacy, Tokyo, Japan.
Sonoda
Y
Y
Ishida
K
K
Sato
Y
Y
Sekigawa
Y
Y
Fukuhara
M
M
D000818:Animals; D002846:Chromatography, Affinity; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007700:Kinetics; D008099:Liver / Q000254:growth & development; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D008970:Molecular Weight; D010088:Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D058886:Sterol 14-Demethylase; D013379:Substrate Specificity
C548417:Cyp51 protein, rat; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D058886:Sterol 14-Demethylase