A hemoprotein. This enzyme is an isoform of aldehyde oxidase (EC 1.2.3.1). It has a preference for aldehydes having an indole-ring structure as substrate [6,7]. It may play a role in plant hormone biosynthesis as its activity is higher in the auxin-overproducing mutant, super-root1, than in wild-type Arabidopsis thaliana [7]. While (indol-3-yl)acetaldehyde is the preferred substrate, it also oxidizes indole-3-carbaldehyde and acetaldehyde, but more slowly. The enzyme from maize contains FAD, iron and molybdenum [4].
