FIGURE 4.

Metabolic pathway of dissimilatory sulfate reduction showing the active uptake of SO₄^2- by a membrane-bound sulfate transporter, the four steps in the reduction pathway, and the passive release of H₂S (see text). Abbreviations: Sat, ATP sulfurylase; APS, adenosine-5′-phosphosulfate; Apr, adenylyl-sulfate reductase; Dsr, dissimilatory (bi)sulfite reductase; ETC, membrane-bound electron transfer complex. Sulfur is green while electron transfers to sulfur are indicated in red. After Santos et al. (2015) and Sim et al. (2017).