Diversity of l-Methionine Catabolism Pathways in Cheese-Ripening Bacteria

Enzymatic activities that could be involved in methanethiol generation in five cheese-ripening bacteria were assayed, and the major sulfur compounds produced were identified. l-Methionine and α-keto-γ-methyl-thio-butyric acid demethiolating activities were detected in whole cells and cell extracts (CFEs) of all the bacteria tested. No l-methionine deaminase activity could be detected in any of the ripening bacteria and l-methionine aminotransferase was detected in CFEs of Brevibacterium linens, Micrococcus luteus, and Corynebacterium glutamicum. The results suggest that several pathways for l-methionine catabolism probably coexist in these ripening bacteria.