Probably acts as a terminal oxidase of plasma electron transport from cytosolic NAD(P)H via hydroquinones to acceptors at the cell surface. Hydroquinone oxidase activity alternates with a protein disulfide-thiol interchange/oxidoreductase activity which may control physical membrane displacements associated with vesicle budding or cell enlargement. The activities oscillate with a period length of 24 minutes and play a role in control of the ultradian cellular biological clock. {ECO:0000269|PubMed:11360993, ECO:0000269|PubMed:12565167, ECO:0000269|PubMed:17027975, ECO:0000269|PubMed:19055324}. This is the function of Ensembl gene identifier ENSG00000120658 (ENOX1, ecto-NOX disulfide-thiol exchanger 1).