Enables cytochrome-c oxidase activity. Predicted to be involved in mitochondrial cytochrome c oxidase assembly. Located in mitochondrion. Is expressed in brain; embryo; and skeletal muscle. Used to study Leigh disease. Human ortholog(s) of this gene implicated in Charcot-Marie-Tooth disease type 4K; Leigh disease; and cytochrome-c oxidase deficiency disease. Orthologous to human SURF1 (SURF1 cytochrome c oxidase assembly factor). [provided by Alliance of Genome Resources, Apr 2022]