In enzymology, an acyl-CoA oxidase (EC 1.3.3.6) is an enzyme that catalyzes the chemical reaction acyl-CoA + O2↔ trans-2, 3-dehydroacyl-CoA + H2O2. Thus, the two substrates of this enzyme are acyl-CoA and O2, whereas its two products are trans-2, 3-dehydroacyl-CoA and H2O2. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with oxygen as acceptor. This enzyme participates in 3 metabolic pathways: fatty acid metabolism, polyunsaturated fatty acid biosynthesis, and ppar signaling pathway. It employs one cofactor, FAD.