Methionine catabolism in Saccharomyces cerevisiae.
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.
Perpète
Philippe
P
Unité de Brasserie et des Industries Alimentaires, Université Catholique de Louvain, Louvain-la-Neuve, Belgium.
Duthoit
Olivier
O
De Maeyer
Simon
S
Imray
Louise
L
Lawton
Andrew I
AI
Stavropoulos
Konstantinos E
KE
Gitonga
Virginia W
VW
Hewlins
Michael J E
MJ
Dickinson
J Richard
JR
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
D003470:Culture Media; D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds; C005231:methylmercaptan; D008715:Methionine