COX5B
COX5B (cytochrome c oxidase subunit 5B, formerly cytochrome c oxidase subunit Vb) is a nuclear-encoded component of cytochrome c oxidase, the terminal enzyme of the mitochondrial electron transport chain. It sits in the mitochondrial inner membrane, where complex IV drives oxidative phosphorylation. Browse Assay Genie's current range of COX5B research reagents below, or read on for the biology behind the target.
COX5B is a component of cytochrome c oxidase, the last enzyme in the mitochondrial electron transport chain, which drives oxidative phosphorylation. The respiratory chain contains three multisubunit complexes: succinate dehydrogenase (complex II), ubiquinol-cytochrome c oxidoreductase (complex III) and cytochrome c oxidase (complex IV). Together they transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient across the inner membrane that drives transmembrane transport and the ATP synthase.
Cytochrome c oxidase catalyses the reduction of oxygen to water. Electrons from reduced cytochrome c in the intermembrane space pass through the dinuclear copper A centre of subunit 2 and heme A of subunit 1 to the active site in subunit 1, a binuclear centre formed by heme A3 and copper B. This centre reduces molecular oxygen to two water molecules using four electrons from cytochrome c and four protons from the mitochondrial matrix.
According to the NCBI Gene summary, the complex consists of 13 mitochondrial- and nuclear-encoded subunits. The mitochondrially encoded subunits perform electron transfer and proton pumping, while the functions of the nuclear-encoded subunits are unknown, although they may contribute to regulation and assembly of the complex. The COX5B gene encodes nuclear-encoded subunit Vb of the human enzyme, and the protein belongs to the cytochrome c oxidase subunit 5B family. HGNC places it in the group of mitochondrial complex IV cytochrome c oxidase subunits. Mouse and rat both carry a Cox5b ortholog.
COX5B is part of complex IV, the terminal enzyme of the electron transport chain that drives oxidative phosphorylation.
Nuclear-encoded subunits such as COX5B may play a role in the regulation and assembly of cytochrome c oxidase.
Cytochrome c oxidase reduces molecular oxygen to water, making its subunits relevant to studies of electron and proton transfer.
The complex contributes to the proton electrochemical gradient across the inner mitochondrial membrane that supports ATP synthase activity.
COX5B is a subunit of cytochrome c oxidase (complex IV), the last enzyme of the mitochondrial electron transport chain. The complex reduces oxygen to water and helps build the proton gradient used by ATP synthase. The specific role of the nuclear-encoded subunits is unknown, but they may aid regulation and assembly.
The HGNC full name is cytochrome c oxidase subunit 5B, and the previous name is cytochrome c oxidase subunit Vb. UniProt lists the protein as cytochrome c oxidase subunit 5B, mitochondrial. No alternative gene symbols are recorded, so searches for COX5B or subunit Vb refer to the same target.
Yes. Mouse and rat each have an ortholog named Cox5b, so the subunit is present in common rodent models of mitochondrial function. Check the datasheet of any product for its validated reactivity before using it with a particular species.
Other cytochrome c oxidase subunits and assembly factors that function alongside COX5B in mitochondrial complex IV.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P10606; product specifications from Assay Genie datasheets.