This cytochrome P450 (heme-thiolate) enzyme is involved in the biosynthesis of glucosinolates in plants. The enzyme catalyses the N-hydroxylation of aromatic aldoximes derived from L-tryptophan and L-phenylalanine, forming an aci-nitro intermediate that reacts non-enzymically with glutathione to produce an N-alkyl-thiohydroximate adduct, the committed precursor of glucosinolates. In the absence of glutathione, the enzyme is suicidal, probably due to interaction of the reactive aci-nitro compound with catalytic residues in the active site.