Evidence for oxidative phosphorylation during the reduction of sulfate with hydrogen by Desulfovibrio desulfuricans.

Desulfovitio d&dfUTiCam is an obligately anaerobic organism that can bc grown heterotrophically with sulfate and an organic electron donor or autotrophically with sulfate, hydrogen, and CO* (1). The presence of sulfate is obligatory for growth both with hydrogen and organic electron donors, except in the case of pyruvate (2). During growth, large amounts of sulfide are produced from the sulfate which is for this organism the terminal electron acceptor in anaerobic respiration (3). Intact cells of D. dtxuljuricans reduce sulfate, sulfite, and thiosulfate to sulfide with molecular hydrogen (4). Sulfite and thiosulfate are reduced by cell-free extracts of this organism to sulfide in the presence of hydrogen (5). However, extracts do not reduce sulfate in the presence of hydrogen. Peck (6) has demonstrated that cell-free extracts require adenosine 5’-triphosphate for the reduction of sulfate with molecular hydrogen (see also (7)). The initial step in sulfate reduction is the formation of adenosine 5’-phosphosulfate’ from ATP and sulfate by the enzyme ATP-sulfurylase (S)l as shown in Equation l.*