Succinic Acid Production by Rumen Bacteria. III. Enzymic Studies on the Formation of Succinate by Ruminococcus Flavefaciens

Abstract

Enzymes involved in succinic acid production by strain C of R. ftavefacien8 were investigated in cell-free extracts. The results indicate that phosphoenolpyruvate is carboxylated by a phosphoenolpyruvate carboxykinase which uses GDP as phosphate acceptor, and that the oxaloacetate so formed is converted to succinate via a DPNH-dependent malate dehydrogenase, a fumarate hydratase, and a DPNH-dependent fumarate reductase. Succinate dehydrogenase activity was also observed which differed markedly from fumarate reductase in that DPN+ was not reduced and in inhibition characteristics.