Contains FAD. This eukaryotic enzyme, located at the inner mitochondrial membrane, catalyses the first step in the metabolism of sulfide. While both sulfite and glutathione have been shown to act as sulfane sulfur acceptors in vitro, it is thought that the latter acts as the main acceptor in vivo. The electrons are transferred via FAD and quinones to the electron transfer chain. Unlike the bacterial homolog (EC 1.8.5.4, bacterial sulfide:quinone reductase), which repeats the catalytic cycle without releasing the product, producing a polysulfide, the eukaryotic enzyme transfers the persulfide to an acceptor at the end of each catalytic cycle.
