COXII Cytochrome c oxidase is the component of the respiratory chain that catalyzes the reduction of oxygen to water. Subunits 1- 3 form the functional core of the enzyme complex. Subunit 2 transfers the electrons from cytochrome c via its binuclear copper A center to the bimetallic center of the catalytic subunit 1. MTCO2 227 COII Cytochrome c oxidase polypeptide II Cytochrome c oxidase subunit 2 MT-CO2 COX2_HORSE MAYPFQLGFQDATSPIMEELLHFHDHTLMIVFLISSLVLYIISSMLTTKLTHTSTMDAQEVETIWTILPAIILILIALPSLRILYMMDEINNPSLTVKTMGHQWYWSYEYTDYEDLTFDSYMIPTSDLKPGELRLLEVDNRVVLPMEMTIRMLISSEDVLHSWAVPSLGLKTDAIPGRLNQTTLVASRPGLYYGQCSEICGSNHSFMPIVLELVPLKHFEEWSASML