Formation of Thiosulfate from Sulfite byDesulfovibrio vulgaris

Abstract

Crude extracts of Desulfovibrio vulgaris reduced sulfite to sulfide. Ammonium sulfate fractionation of crude extracts separated a thiosulfate-forming system from sulfite- and thiosulfate-reductase activities. Further purification by sucrose density centrifugation separated the thiosulfate-forming system into two components, both of which were required for the reaction. In addition to these two components, cytochrome c₃, ferredoxin, and hydrogenase were required to form thiosulfate from sulfite. By absorption spectra and from the effect of pH and substrate concentration, the ionic species acting as the substrate for thiosulfate-formation was concluded to be bisulfite.