title: Different substrate specificities of lanosterol 14a-demethylase (P-45014DM) of Saccharomyces cerevisiae and rat liver for 24-methylene-24,25-dihydrolanosterol and 24,25-dihydrolanosterol.
abstract: The purified lanosterol 14a-demethylase (P-45014DM) of S. cerevisiae catalyzed the 14a-demethylation of 24-methylene-24,25-dihydrolanosterol (24-methylenelanost-8-en-3 beta-ol, 24-methylene-DHL), the natural substrate of the demethylase of filamentous fungi, as well as its natural substrate, lanosterol. Lanosterol 14a-demethylase of rat liver microsomes also catalyzed the 14a-demethylation of 24-methylene-DHL, but the activity was considerably lower than that for lanosterol. The activity of the rat liver enzyme for 24-methylene-DHL was also lower than that for 24,25-dihydrolanosterol (DHL), while the activity of yeast P-45014DM for 24-methylene-DHL was considerably higher than that for DHL. Since 24-substituted sterols are not found in mammals and DHL is not an intermediate of ergosterol biosynthesis by yeast, above-mentioned different substrate specificities between the yeast and the mammalian 14a-demethylases may reflect certain evolutional alteration in their active sites in relation to the difference in their sterol biosynthetic pathways.
authors.affiliation: Faculty of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Aoyama
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D003577:Cytochrome P-450 Enzyme System / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000378:metabolism; D008099:Liver / Q000201:enzymology*; D008297:Male; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D058886:Sterol 14-Demethylase; D013379:Substrate Specificity
chemical_list: C548417:Cyp51 protein, rat; D007810:Lanosterol; C014520:ebericol; C015316:lanostenol; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D058886:Sterol 14-Demethylase