Portal de Periódicos da CAPES

Methionine catabolism in Saccharomyces cerevisiae

2006; Oxford University Press; Volume: 6; Issue: 1 Linguagem: Inglês

10.1111/j.1567-1356.2005.00005.x

1567-1364

Philippe Perpà ̈te, Olivier Duthoit, Simon De Maeyer, Louise Imray, Andrew I. Lawton, Konstantinos E. Stavropoulos, Virginia W. Gitonga, M. J. E. Hewlins, John R. Dickinson,

GABA and Rice Research

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.