Methionine catabolism in Saccharomyces cerevisiae

• Published in: FEMS yeast research Vol. 6; no. 1; pp. 48 - 56
• Main Authors: Perpète, Philippe, Duthoit, Olivier, De Maeyer, Simon, Imray, Louise, Lawton, Andrew I., Stavropoulos, Konstantinos E., Gitonga, Virginia W., Hewlins, Michael J. E., Richard Dickinson, J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.01.2006; Blackwell Science Ltd; Oxford University Press
• Subjects: Amino acids; Biotechnology - methods; Culture Media; Decarboxylation; demethiolase activity; Gas Chromatography-Mass Spectrometry; Magnetic Resonance Spectroscopy; Methanethiol; Methionine; Methionine - metabolism; methionine catabolism; methionol; Mutants; Mutation; NMR; Nuclear magnetic resonance; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Sulfhydryl Compounds - metabolism; Yeast; demethiolase activity; methanethiol; methionol; methionine catabolism
• ISSN: 1567-1356; 1567-1364
• DOI: 10.1111/j.1567-1356.2005.00005.x

Abstract The catabolism of methionine to methionol and methanethiol in Saccharomyces cerevisiae was studied using 13C NMR spectroscopy, GC-MS, enzyme assays and a number of mutants. Methionine is first transaminated to α-keto-γ-(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 α-keto-γ-(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 α-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.