COX5B Protein, Human (His)

COX5B, an integral component of the cytochrome c oxidase, stands as the final enzyme in the mitochondrial electron transport chain, orchestrating oxidative phosphorylation. This respiratory chain encompasses three crucial 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)—cooperatively facilitating the transfer of electrons derived from NADH and succinate to molecular oxygen. This intricate process generates an electrochemical gradient across the inner membrane, propelling transmembrane transport and driving ATP synthase. Cytochrome c oxidase serves as the linchpin of the respiratory chain, catalyzing the reduction of oxygen to water. Electrons, originating from reduced cytochrome c in the intermembrane space, traverse through intermediates like the dinuclear copper A center (CU(A)) in subunit 2 and heme A in subunit 1. Ultimately, this electron transfer converges at the active site in subunit 1, forming a binuclear center (BNC) composed of heme A3 and copper B (CU(B)). The BNC efficiently reduces molecular oxygen to two water molecules, utilizing four electrons from cytochrome c in the intermembrane space and four protons from the mitochondrial matrix. COX5B plays a pivotal role in energy metabolism, contributing significantly to the intricate processes of oxidative phosphorylation.