title: Methionine catabolism in Saccharomyces cerevisiae.
abstract: The catabolism of methionine to methionol and methanethiol in Saccharomyces cerevisiae was studied using (13)C NMR spectroscopy, GC-MS, enzyme assays and a number of mutants. Methionine is first transaminated to alpha-keto-gamma-(methylthio)butyrate. Methionol is formed by a decarboxylation reaction, which yields methional, followed by reduction. The decarboxylation is effected specifically by Ydr380wp. Methanethiol is formed from both methionine and alpha-keto-gamma-(methylthio)butyrate by a demethiolase activity. In all except one strain examined, demethiolase was induced by the presence of methionine in the growth medium. This pathway results in the production of alpha-ketobutyrate, a carbon skeleton, which can be re-utilized. Hence, methionine catabolism is more complex and economical than the other amino acid catabolic pathways in yeast, which use the Ehrlich pathway and result solely in the formation of a fusel alcohol.
authors.affiliation: Unité de Brasserie et des Industries Alimentaires, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Perpète
authors.forename: Olivier
authors.initials: O
authors.lastname: Duthoit
authors.forename: Simon
authors.initials: S
authors.lastname: De Maeyer
authors.forename: Louise
authors.initials: L
authors.lastname: Imray
authors.forename: Andrew I
authors.initials: AI
authors.lastname: Lawton
authors.forename: Konstantinos E
authors.initials: KE
authors.lastname: Stavropoulos
authors.forename: Virginia W
authors.initials: VW
authors.lastname: Gitonga
authors.forename: Michael J E
authors.initials: MJ
authors.lastname: Hewlins
authors.forename: J Richard
authors.initials: JR
authors.lastname: Dickinson
mesh_terms: D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D008715:Methionine / Q000378:metabolism*; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D003470:Culture Media; D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds; C005231:methylmercaptan; D008715:Methionine