Cytochrome c oxidase subunit 3 (EC 7.1.1.9) (Cytochrome c oxidase polypeptide III)
1_MTHQS 6_ HAYHM 11_ VKPSP 16_ WPLTG 21_ ALSAL 26_ LMTSG 31_ LAMWF 36_ HFHSM 41_ TLLML 46_ GLLTN 51_ TLTMY 56_ QWWRD 61_ VTRES 66_ TYQGH 71_ HTPPV 76_ QKGLR 81_ YGMIL 86_ FITSE 91_ VFFFA 96_ GFFWA 101_ FYHSS 106_ LAPTP 111_ QLGGH 116_ WPPTG 121_ ITPLN 126_ PLEVP 131_ LLNTS 136_ VLLAS 141_ GVSIT 146_ WAHHS 151_ LMENN 156_ RNQMI 161_ QALLI 166_ TILLG 171_ LYFTL 176_ LQASE 181_ YFESP 186_ FTISD 191_ GIYGS 196_ TFFVA 201_ TGFHG 206_ LHVII 211_ GSTFL 216_ TICFI 221_ RQLMF 226_ HFTSK 231_ HHFGF 236_ EAAAW 241_ YWHFV 246_ DVVWL 251_ FLYVS 256_IYWWG
1: Component of the cytochrome c oxidase, the last enzyme in the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over the inner membrane that drives transmembrane transport and the ATP synthase. Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Electrons originating from reduced cytochrome c in the intermembrane space (IMS) are transferred via the dinuclear copper A center (CU(A)) of subunit 2 and heme A of subunit 1 to the active site in subunit 1, a binuclear center (BNC) formed by heme A3 and copper B (CU(B)). The BNC reduces molecular oxygen to 2 water molecules using 4 electrons from cytochrome c in the IMS and 4 protons from the mitochondrial matrix