title: Identification of 24-methylene-24,25-dihydrolanosterol as a precursor of ergosterol in the yeasts Schizosaccharomyces pombe and Schizosaccharomyces octosporus.
abstract: Study of the plasma membrane sterol composition in the yeasts Schizosaccharomyces pombe and Schizosaccharomyces octosporus revealed the presence of ergosterol, lanosterol, dehydroergosterol, fecosterol, episterol and 24-methylene-24,25-dihydrolanosterol (eburicol), a C-31 derivative. The growth of both yeasts in the presence of ketoconazole led to a decrease by 85% of the ergosterol content while the levels of lanosterol and eburicol increased. This suggests that in the biosynthetic pathway of ergosterol in Schizosaccharomyces species, the transmethylation process on the C-24 may occur directly on lanosterol and not only on zymosterol. On the other hand, it cannot be excluded that in the genus Schizosaccharomyces two routes exist from lanosterol to ergosterol: the classical one via a direct C-14, C-4 demethylation of lanosterol and the second one via the formation of a C-31 derivative followed by demethylations.
authors.affiliation: Laboratoire de Biochimie Microbienne, G.E.V.S.M., Université Henri Poincaré, Nancy l. Faculté de Pharmacie, France.
authors.forename: N
authors.initials: N
authors.lastname: Harmouch
authors.forename: J
authors.initials: J
authors.lastname: Coulon
authors.forename: R
authors.initials: R
authors.lastname: Bonaly
mesh_terms: D001665:Binding Sites; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004875:Ergosterol / Q000096:biosynthesis* / Q000737:chemistry; D007654:Ketoconazole / Q000494:pharmacology; D007810:Lanosterol / Q000031:analogs & derivatives* / Q000378:metabolism; D008745:Methylation; D012568:Schizosaccharomyces / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D013045:Species Specificity; D013261:Sterols / Q000378:metabolism
chemical_list: D013261:Sterols; D007810:Lanosterol; C014520:ebericol; D007654:Ketoconazole; D004875:Ergosterol