title: Accumulation of zymosterol in yeast grown in the presence of ethionine.
abstract: In order to identify the methyl acceptor for the methylation of sterol side-chains in ergosterol biosynthesis, Saccharomyces cerevisiae (wild type) was grown in the presence and absence of ethionine which was expected to be an inhibitor of the methylation. Gas-liquid chromatographic analyses of the sterols in the cells grown in the absence of ethionine showed that ergosterol was the most abundant sterol. On the other hand, a sterol, named sterol Z, accounted for more than 50% of the total sterols in the cells grown in the presence of ethionine. As a result of experiments to raise the yield of sterol Z, the best concentration of DL-ethionine for the production was found to be 1.0 mM. The use of the methionine-less mutant was less effective for the production of sterol Z. Sterol Z was isolated by repeated TLC and was identified as zymosterol from its melting point, GLC and mass spectrometry. The role of zymosterol and other sterols as the methyl-acceptor sterol in ergosterol biosynthesis is also discussed.
mesh_terms: D002775:Cholestadienols / Q000378:metabolism; D003513:Cycloheximide / Q000494:pharmacology; D004875:Ergosterol / Q000096:biosynthesis*; D005001:Ethionine / Q000378:metabolism; D008715:Methionine / Q000378:metabolism; D008745:Methylation; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013261:Sterols / Q000378:metabolism*
chemical_list: D002775:Cholestadienols; D013261:Sterols; D003513:Cycloheximide; D008715:Methionine; D005001:Ethionine; D004875:Ergosterol