ATP-driven succinate oxidation in the catabolism of Desulfuromonas acetoxidans

Abstract

The oxidation of succinate with elemental sulphur in Desulfuromonas acetoxidans was investigated using a membrane preparation of this bacterium. The following results were obtained: 1. The preparation catalyzed the oxidation of succinate with sulphur and NAD. These reactions were dependent on ATP and were abolished by the presence of protonophores or dicyclohexylcarbodiimide (DCCD). 2. The membrane preparation also catalyzed the reduction of fumarate with H2S or with NADH. These activities were not dependent on ATP and were not affected by protonophores or DCCD. 3. By extraction-reincorporation experiments it could be shown that menaquinone is involved in electron transport between H2S and fumarate and between NADH and fumarate. 4. The membrane fraction catalyzed the reduction of the water-soluble menaquinone-analogue dimethylnaphthoquinone (DMN) by succinate, H2S, or NADH, and the oxidation of DMNH2 by fumarate. These activities were not dependent on the presence of menaquinone and were not influenced by ATP. 5. The activities involving succinate oxidation or fumarate reduction were similarly sensitive to 2(n-nonyl)-4-hydroxyquinoline-N-oxide, while H2S and NADH oxidation by DMN were not affected by the inhibitor.