title: 4-Methylzymosterone and Other Intermediates of Sterol Biosynthesis from Yeast Mutants Engineered in the ERG27 Gene Encoding 3-Ketosteroid Reductase.
abstract: Studies in the post-squalene section of sterol biosynthesis may be hampered by the poor availability of authentic standards. The present study used different yeast strains engineered in 3-ketosteroid reductase (Erg27p) to obtain radioactive and non-radioactive intermediates of sterol biosynthesis hardly or not available commercially. Non-radioactive 3-keto 4-monomethyl sterones were purified from non-saponifiable lipids extracted from cells bearing point-mutated 3-ketosteroid reductase. Two strategies were adopted to prepare the radioactive compounds: (1) incubation of cell homogenates of an ERG27-deletant strain with radioactive lanosterol, (2) incubation of growing cells of a strain expressing point-mutated 3-ketosteroid reductase with radioactive acetate. Chemical reduction of both radioactive and non-radioactive 3-keto sterones gave the physiological 3-β OH sterols, as well as the non-physiological 3-α OH isomers. This combined biological and chemical preparation procedure provided otherwise unavailable or hardly available 4-mono-methyl intermediates of sterol biosynthesis, paving the way for research into their roles in physiological and pathological conditions.
authors.affiliation: Department of Science and Drug Technology, University of Torino, Via P. Giuria 9, 10125, Turin, Italy.
authors.forename: Terenzio
authors.initials: T
authors.lastname: Ferrante
authors.affiliation: Department of Science and Drug Technology, University of Torino, Via P. Giuria 9, 10125, Turin, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Barge
authors.affiliation: Department of Science and Drug Technology, University of Torino, Via P. Giuria 9, 10125, Turin, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Taramino
authors.affiliation: Department of Science and Drug Technology, University of Torino, Via P. Giuria 9, 10125, Turin, Italy. simona.oliaro@unito.it.
authors.forename: Simonetta
authors.initials: S
authors.lastname: Oliaro-Bosso
authors.affiliation: Department of Science and Drug Technology, University of Torino, Via P. Giuria 9, 10125, Turin, Italy. gianni.balliano@unito.it.
authors.forename: Gianni
authors.initials: G
authors.lastname: Balliano
mesh_terms: D005818:Genetic Engineering; D009154:Mutation; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D013261:Sterols / Q000096:biosynthesis*
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D013261:Sterols; D010088:Oxidoreductases; C400426:ERG27 protein, S cerevisiae
keywords: 3-Ketosteroid reductase; 4-Methylfecosterone; 4-Methylzymosterone; Engineered yeast strains; Post-squalene sterol biosynthesis