In enzymology, a sulfite dehydrogenase (EC 1.8.2.1) is an enzyme that catalyzes the chemical reaction

sulfite + 2 ferricytochrome c + H₂O sulfate + 2 ferrocytochrome c + 2 H⁺

The 3 substrates of this enzyme are sulfite, ferricytochrome c, and H₂O, whereas its 3 products are sulfate, ferrocytochrome c, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donor with a cytochrome as acceptor. The systematic name of this enzyme class is sulfite:ferricytochrome-c oxidoreductase. Other names in common use include sulfite cytochrome c reductase, sulfite-cytochrome c oxidoreductase, and sulfite oxidase. This enzyme participates in sulfur metabolism.

• Charles AM, Suzuki I (1966). "Purification and properties of sulfite:cytochrome c oxidoreductase from Thiobacillus novellus". Biochim. Biophys. Acta. 128: 522–534. doi:10.1016/0926-6593(66)90013-0.
• Lu WP, Kelly DP (1984). "Properties and role of sulphite:cytochrome c oxidoreductase purified from Thiobacillus versutus (A2)". J. Gen. Microbiol. 130: 1683–1692. doi:10.1099/00221287-130-7-1683.