Deformylation of 32-oxo-24,25-dihydrolanosterol by the purified cytochrome P-45014DM (lanosterol 14 alpha-demethylase) from yeast evidence confirming the intermediate step of lanosterol 14 alpha-demethylation.
32-Oxo-24,25-dihydrolanosterol (32-oxo-DHL) was deformylated to 4,4-dimethylcholesta-8,14-dien-3 beta-ol, the product of 14 alpha-demethylation of 24,25-dihydro-lanosterol (DHL), by the reconstituted lanosterol 14 alpha-demethylase system consisting of cytochrome P-45014DM and NADPH-cytochrome P-450 reductase of yeast. Affinity of 32-oxo-DHL to the cytochrome was considerably higher than those of lanosterol and DHL, and the rate of deformylation of 32-oxo-DHL was faster than the rate of demethylation of lanosterol and DHL. Spectral analysis of the 32-oxo-DHL complex of cytochrome P-45014DM suggested the interaction between the 32-aldehyde group and the heme iron. These observations, together with our preceding findings on the metabolism of 32-hydroxy-24,25-dihydrolanosterol (Aoyama, Y., Yoshida, Y., Sonoda, Y., and Sato, Y. (1987) J. Biol. Chem. 262, 1239-1243), indicate that the 14 alpha-demethylation of lanosterol catalyzed by cytochrome P-45014DM proceeds with three step monooxygenations via the 32-hydroxy and 32-oxo intermediates, and the cytochrome mediates this sequential reaction without releasing the intermediates.
Aoyama
Y
Y
Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya, Japan.
Yoshida
Y
Y
Sonoda
Y
Y
Sato
Y
Y
D001667:Binding, Competitive; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D007700:Kinetics; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000378:metabolism*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013053:Spectrophotometry; D058886:Sterol 14-Demethylase
D007810:Lanosterol; C032444:lanosten-3-ol-32-al; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D058886:Sterol 14-Demethylase; D009251:NADPH-Ferrihemoprotein Reductase