Induction of Malic Enzyme and of Oxalacetate Decarboxylase in Three Lactic Acid Bacteria

SUMMARY: The presence of inducible, DPN-specific malic enzymes have been demonstrated in Lactobacillus plantarum, L. casei and Streptococcus faecalis. Of 30 compounds tested, only l-malate induced the synthesis of malic enzyme in L. plantarum.

The possibility that the malic enzymes of these three organisms are bifunctional proteins which have separate sites to decarboxylate oxalacetate has been excluded. In addition to l-malate, three compounds, oxalacetate, acetoacetate and α-keto- glutarate, induce the synthesis of oxalacetate decarboxylase even though they cannot induce the synthesis of malic enzyme. The oxalacetate decarboxylation system consists of an oxalacetate decarboxylase and an oxalacetate permease. Malate can induce the synthesis of only oxalacetate decarboxylase and not oxalacetate permease.