Drake H L, Akagi J M
J Bacteriol. 1977 Oct;132(1):132-8. doi: 10.1128/jb.132.1.132-138.1977.
An enzyme that formed thiosulfate from bisulfite and trithionate was purified from extracts of Desulfovibrio vulgaris. This enzyme, designated as "thiosulfate-forming" enzyme, required the presence of both bisulfite and trithionate. Various 35S-labeling studies showed that thiosulfate was formed from bisulfite and the inner sulfur atom of trithionate. This involved a nucleophilic attack by the bisulfite ion, resulting in the displacement of the two outer sulfonate groups of trithionate that recycled to participate as free bisulfite in subsequent reactions. This reaction required a reduction, presumably by a concerted mechanism with thiosulfate formation. The natural electron carrier cytochrome c3 participated in this reductive formation of thiosulfate. This reaction was coupled to the bisulfite reductase-catalyzed reaction, which resulted in the reconstruction of a thiosulfate-forming pathway from bisulfite.
从普通脱硫弧菌提取物中纯化出一种能将亚硫酸氢盐和连三硫酸盐转化为硫代硫酸盐的酶。这种酶被命名为“硫代硫酸盐形成”酶，它需要亚硫酸氢盐和连三硫酸盐同时存在。各种35S标记研究表明，硫代硫酸盐是由亚硫酸氢盐和连三硫酸盐的内部硫原子形成的。这涉及亚硫酸氢根离子的亲核攻击，导致连三硫酸盐的两个外部磺酸根基团被取代，这些磺酸根基团循环后以游离亚硫酸氢盐的形式参与后续反应。该反应需要还原作用，推测是通过与硫代硫酸盐形成协同机制进行的。天然电子载体细胞色素c3参与了硫代硫酸盐的这种还原形成过程。该反应与亚硫酸氢盐还原酶催化的反应相偶联，从而从亚硫酸氢盐重建了一条硫代硫酸盐形成途径。
