Bisulfite reductase, is an enzyme from the family oxidoreductases and is made up of 4 subtrates:  trithionate, acceptor, H2O, and OH.
Other names in common use include bisulfite reductase, dissimilatory sulfite reductase, desulfoviridin, desulforubidin, desulfofuscidin, dissimilatory-type sulfite reductase, and trithionate:(acceptor) oxidoreductase. In enzymology, a hydrogensulfite reductase (EC ) is an enzyme that catalyzes the chemical reaction The 4 substrates of this enzyme are trithionate, acceptor, H2O, and OH-, whereas its two products are bisulfite and reduced acceptor. This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with other acceptors. 
