Involved in the first step of peroxisomal beta-oxidation by catalyzing the desaturation of fatty acid-derived side chains. Activated by ATP (By similarity). ATP binding leads to a conformational change that promotes FAD cofactor binding and enzyme activity (By similarity). ATP binding likely occurs during acox-1.5 folding and/or dimer formation (By similarity). Lipid metabolism; peroxisomal fatty acid beta-oxidation. Homodimer. Belongs to the acyl-CoA oxidase family.