Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In enzymology, a sulfur oxygenase/reductase (EC 1.13.11.55) is an enzyme that catalyzes the chemical reaction. The 3 substrates of this enzyme are sulfur, H2O, and O2, whereas its 3 products are hydrogen sulfide, bisulfite, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases).