Enables cytochrome-c oxidase activity. Predicted to be involved in mitochondrial electron transport, cytochrome c to oxygen. Predicted to be located in mitochondrial inner membrane. Predicted to be part of mitochondrial respiratory chain complex IV. Human ortholog(s) of this gene implicated in cytochrome-c oxidase deficiency disease. Orthologous to human COX5A (cytochrome c oxidase subunit 5A). [provided by Alliance of Genome Resources, Apr 2022]