Cytochrome c oxidase subunit 2

Cytochrome c oxidase subunit 2 (MT-CO2) is a component of Complex IV (cytochrome c oxidase), the terminal enzyme of the mitochondrial electron transport chain. It catalyzes oxygen reduction to water, with the protein serving as a conduit for electron transfer via its dinuclear copper A center (UniProt: P00403).

MT-CO2 is encoded by mitochondrial DNA and is critical for oxidative phosphorylation and ATP generation across tissues. Pathogenic variants in MT-CO2 are associated with mitochondrial complex IV deficiency, a heterogeneous disorder featuring cardiomyopathy, hepatomegaly, muscle weakness, developmental delay, and in severe cases, neonatal-lethal hypertrophic cardiomyopathy or Leigh syndrome (UniProt: P00403).

MT-CO2 is tagged as relevant to Alzheimer's Disease; however, the direction of regulation in AD brain tissue is ambiguous across measured subcellular fractions (P2, P3, S2, S3) from post-mortem samples, with a mean log2 fold-change of 0.62 relative to age-matched controls (Chaparral AD proteomics).