OCCURRENCE OF A MODIFIED ENTNER-DOUDOROFF PATHWAY IN CLOSTRIDIUM ACETICUM

0761 05 1. The pathway of gluconate fermentation by C. aceticum has been investigated. Gluconate is degraded via 2-keto-3-deoxygluconate (KDG)1 and 2-keto-3-deoxy-6-phosphogluconate (KDPG) which is cleaved to yield pyruvate and glyceraldehyde-3-phosphate. 2. Gluconate dehydrase was present in high activity in cells grown on gluconate, but not in cells grown on fructose. The amounts of KDG kinase and KDPG aldolase in gluconate and fructose grown cells did not differ significantly. 3. The three enzymes involved in gluconate breakdown have been characterized with respect to their requirements for reducing agents and metal ions. Gluconate dehydrase requires a sulfhydryl compound and ferrous ions for activity, KDG kinase a divalent metal ion for activity. Sulfhydryl compounds and metal ions are not necessary for KDPG aldolase activity. 4. When suspensions of washed cells of C. aceticum fermented gluconate, KDG was accumulated in the medium. © 1969 Springer-Verlag.