<p>This entry describes the C subunit of the NADH dehydrogenase complex I in bacteria, as well as many instances of the corresponding mitochondrial subunit (NADH dehydrogenase subunit 9) and of the F420H2 dehydrogenase in Methanosarcina. Complex I contains subunits designated A-N. This C subunit often occurs as a fusion protein with the D subunit. This entry excludes the NAD(P)H and plastoquinone-dependent form of chloroplasts and Synechocystis.</p>