Transcriptional analysis of L-methionine catabolism in Brevibacterium linens ATCC9175

The expression of genes possibly involved in l-methionine and lactate catabolic pathways were performed in Brevibacterium linens (ATCC9175) in the presence or absence of added l-methionine. The expression of 27 genes of 39 selected genes differed significantly in l-methionine-enriched cultures. The expression of the gene encoding l-methionine γ-lyase (MGL) is high in l-methionine-enriched cultures and is accompanied by a dramatic increase in volatile sulfur compounds (VSC) biosynthesis. Several genes encoding α-ketoacid dehydrogenase and one gene encoding an acetolactate synthase were also up-regulated by l-methionine, and are probably involved in the catabolism of α-ketobutyrate, the primary degradation product of l-methionine to methanethiol. Gene expression profiles together with biochemical data were used to propose catabolic pathways for l-methionine in B. linens and their possible regulation by l-methionine.