(C) BN-PAGE was followed by CI-IGA assay and immunoblotting with the indicated antibodies (in brackets). The identity of the MRC complexes and SCs is: I+III2+IV1, SC containing CI, CIII2, and CIV; I+III2, SC containing CI and CIII2; I+III2plus, SC containing CI, CIII2 and a COX1-submodule; III2+IV, SC containing CIII2 and CIV; I, complex I; III2, CIII dimer; IV2, CIV dimer; subCOX1, COX1-containing subcomplexes. 