The role of lipoic acid in product formation by Enterococcus faecalis NCTC 775 and reconstitution in vivo and in vitro of the pyruvate dehydrogenase complex

The function of the pyruvate dehydrogenase complex (PDC) in the development of several fermentation products is analyzed by Enterococcus faecalis. Very little activity in vivo and vitro was identified in PDC when the organism was grown on a medium devoid of lipoic acid. Acetoin was a common product in the absence of lopoic acid, but in its presence acetoin was generated only when the intracellular pyruvate concentration was comparatively large.