In enzymology, D-arabinono-1,4-lactone oxidase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are D-arabinono-1,4-lactone and oxygen. Its products are D-erythro-ascorbic acid and hydrogen peroxide.
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.