<p>Members of this protein family represent cytochrome c552, a component of cytochrome c nitrite reductase, which is known more formally as nitrite reductase (cytochrome; ammonia-forming, <db_xref db="EC" dbkey="1.7.2.2"/>). Nitrite can be reduced by several enzymes:</p><ul> <li> <db_xref db="EC" dbkey="1.7.2.2"/> reduces nitrite all the way to ammonia, rather than to ammonium hydroxide (ammonia:ferricytochrome-c oxidoreductase),</li> <li> <db_xref db="EC" dbkey="1.7.1.4"/> (ammonium-hydroxide:NAD(P)+ oxidoreductase), </li> <li> <db_xref db="EC" dbkey="1.7.2.1"/> nitrite reductase (NO-forming) (nitric-oxide:ferricytochrome-c oxidoreductase). </li></ul> <p>Some examples of <db_xref db="EC" dbkey="1.7.2.2"/> occur in a seven gene system that enables formate-dependent nitrite reduction, but it can also be found in simpler contexts. All members of this protein family, however, do belong to the formate-dependent system of nitrite reduction.</p> Formate-dependent cytochrome c nitrite reductase, c552 subunit