Required for the import and folding of small cysteine-containing proteins in the mitochondrial intermembrane space (Probable). Involved in the mitochondrial oxidative folding of the copper-zinc superoxide dismutase CSD1, the copper chaperone for superoxide dismutase CCS, and subunits of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I). Involved in the peroxisomal oxidative folding of the copper-zinc superoxide dismutase CSD3, and the fatty acid beta-oxidation multifunctional protein AIM1