Claim: Hydrogensulfite reductase(EC 1.8.99.3) is an enzyme from the family oxidoreductases and is made up of 4 subtrates:  trithionate, acceptor, H2O, and OH and its  two products,  bisulfite and reduced acceptor.
Evidence: In enzymology, a hydrogensulfite reductase (EC ) is an enzyme that catalyzes the chemical reaction This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with other acceptors. The 4 substrates of this enzyme are trithionate, acceptor, H2O, and OH-, whereas its two products are bisulfite and reduced acceptor.