The enzyme is part of the Sox enzyme system, which participates in a bacterial thiosulfate oxidation pathway that produces sulfate. The enzyme from the bacterium Paracoccus pantotrophus contains a molybdoprotein component and a diheme c-type cytochrome component. The enzyme successively oxidizes the outer sulfur atom in [SoxY protein]-S-disulfanyl-L-cysteine, using three water molecules and forming [SoxY protein]-S-sulfosulfanyl-L-cysteine. During the process, six electrons are transferred to the electron chain via cytochrome c.
