Observations on the Bisulfite Reductase (P582) Isolated from Desulfotomaculum nigrificans

Abstract

The bisulfite reductase (P582) from Desulfotomaculum nigrificans was purified to homogeneity as judged by polyacrylamide gel electrophoresis. By colorimetric methods of analysis, the products of bisulfite reduction by this enzyme were determined to be trithionate, thiosulfate, and sulfide. Of these, trithionate was consistently found to be the major product, whereas the latter two were formed in lesser quantities. When [35S]bisulfite was incorporated as substrate, no labeled sulfide was detected. Furthermore, when trithionate and thiosulfate were isolated from reaction mixtures and chemically degraded, 35S was found in all three sulfur atoms of trithionate; however, only the inner sulfur atom of thiosulfate was radioactive. From these data we conclude that the bisulfite reductase of D. nigrificans reduces bisulfite to trithionate and that thiosulfate and sulfide are endogenous side products of the reaction.

Characterization of a novel thiosulfate-forming enzyme isolated from Desulfovibrio vulgaris

“…Analytical determinations. Thiosulfate and trithionate were determined by the method of Kelly et al (17) as previously described (4). Sulfide was analyzed by the method of Fogo and Popowski (11).…”

“…Trithionate was synthesized by a modification of the method of Roy and Trudinger (26), as described earlier (4 Na235SO4 was periodically monitored by methods previously described (8). Na235SO3 was purchased from New England Nuclear Corp.…”

Product analysis of bisulfite reductase activity isolated from Desulfovibrio vulgaris

“…Parameters such as concentrations of hydrogenase, methyl viologen, substrate, and hydrogen ion were important factors in determining the major end products of the reaction. From 35S-labeling studies, Akagi et al (2) proposed that the bisulfite reductase (P582), isolated from Desulfotomaculum nigrificans, reduced bisulfite to trithionate and that thiosulfate and sulfide were endogenous side products of the reaction. Chambers and Trudinger (3) concluded from their 35S-labeling studies on Desulfovibrio desulfuricans that thiosulfate and trithionate may not be intermediates in the dissimilatory sulfate-reducing process.…”

“…Thiosulfate and trithionate analyses were performed according to Kelly et al. (7) as described previously (2). Sulfide was determined by analyzing the filter paper in the center well by the method of Fogo and Popowski (4).…”

“…Sulfide was determined by analyzing the filter paper in the center well by the method of Fogo and Popowski (4). Radioactive sulfide was analyzed as described earlier (2). Protein was estimated by the method of Lowry et al (14), using bovine serum albumin as a standard.…”