COX5B
Description
The COX5B (cytochrome c oxidase subunit 5B) is a protein-coding gene located on chromosome 2.
COX5B is a subunit of the cytochrome c oxidase complex (complex IV), the last enzyme in the mitochondrial electron transport chain. In humans, it is encoded by the COX5B gene. The enzyme weighs 14 kDa and consists of 129 amino acids. The protein is a subunit of Complex IV, which consists of 13 mitochondrial- and nuclear-encoded subunits. The sequence of subunit Vb is well conserved and includes three conserved cysteines that coordinate the zinc ion. Two of these cysteines are clustered in the C-terminal section of the subunit. The COX5B gene is located on the q arm of chromosome 2 in position 11.2, is made up of 4 exons, and is 2,137 base pairs in length. Cytochrome c oxidase (COX) is the terminal enzyme of the mitochondrial respiratory chain. It is a multi-subunit enzyme complex that couples the transfer of electrons from cytochrome c to oxygen and contributes to a proton electrochemical gradient across the inner mitochondrial membrane to drive ATP synthesis via protonmotive force. The mitochondrially-encoded subunits perform the electron transfer of proton pumping activities.
COX5B is a subunit of cytochrome c oxidase (complex IV), the final enzyme in the mitochondrial electron transport chain. This chain consists of three multi-subunit complexes: succinate dehydrogenase (complex II), ubiquinol-cytochrome c oxidoreductase (complex III), and cytochrome c oxidase (complex IV). These complexes work together to transfer electrons from NADH and succinate to molecular oxygen, creating an electrochemical gradient across the inner mitochondrial membrane. This gradient drives transmembrane transport and powers ATP synthase. COX5B specifically plays a role in the reduction of oxygen to water. Electrons from reduced cytochrome c in the intermembrane space are transferred through the dinuclear copper A center of subunit 2 and heme A of subunit 1 to the active site in subunit 1. This active site, a binuclear center, reduces molecular oxygen to water using four electrons from cytochrome c and four protons from the mitochondrial matrix.
COX5B is also known as COXVB.
Associated Diseases
- endometrial cancer
- breast cancer
- colorectal cancer
- familial progressive hyperpigmentation
- acroleukopathy, symmetric
- hyperpigmentation with or without hypopigmentation, familial progressive
- homocarnosinosis
