Different substrate specificities of lanosterol 14α-demethylase (P-45014DM) of Saccharomyces cerevisiae and rat liver for 24-methylene-24,25-dihydrolanosterol and 24,25-dihydrolanosterol
1991; Elsevier BV; Volume: 178; Issue: 3 Linguagem: Inglês
10.1016/0006-291x(91)91000-3
ISSN1090-2104
Autores Tópico(s)Natural product bioactivities and synthesis
ResumoThe purified lanosterol 14α-demethylase (P-45014DM) of S. cerevisiae catalyzed the 14α-demethylation of 24-methylene-24,25-dihydrolanosterol (24-methylenelanost-8-en-3β-ol, 24-methylene-DHL), the natural substrate of the demethylase of filamentous fungi, as well as its natural substrate, lanosterol. Lanosterol 14α-demethylase of rat liver microsomes also catalyzed the 14α-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 14α-demethylases may reflect certain evolutional alteration in their active sites in relation to the difference in their sterol biosynthetic pathways.
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