In enzymology, a D-arabinono-1,4-lactone oxidase () is an enzyme that catalyzes the chemical reaction D-arabinono-1,4-lactone + O2 D-erythro-ascorbate + H2O2 Thus, the two substrates of this enzyme are D-arabinono-1,4-lactone and O2, whereas its two products are D-erythro-ascorbate and H2O2. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with oxygen as acceptor. The systematic name of this enzyme class is D-arabinono-1,4-lactone:oxygen oxidoreductase. It employs one cofactor, FAD. References EC 1.1.3 Flavoproteins Enzymes of unknown structure