Involved in auxin biosynthesis, but not in the tryptamine or the CYP79B2/B3 branches. Catalyzes in vitro the N-oxidation of tryptamine to form N-hydroxyl tryptamine. Involved during embryogenesis and seedling development. Required for the formation of floral organs and vascular tissues. Belongs to the set of redundant YUCCA genes probably responsible for auxin biosynthesis in shoots. H(+) + indole-3-pyruvate + NADPH + O2 = (indol-3-yl)acetate + CO2 + H2O + NADP(+) Plant hormone metabolism; auxin biosynthesis. Expressed in the apical meristems and young floral primordia. Detected in the floral meristems and at the base of the floral organs. Expression relatively broad during early stages of embryogenesis and more restricted to discrete groups of cells in mature embryos. Later, expression mainly restricted to the cotyledons and the apical meristem. No visible phenotype, due to the redundancy with the other members of the YUCCA family. Belongs to the FMO family. Was initially (PubMed:11209081) thought to be involved in the tryptamine pathway for the biosynthesis of indole-3-acetic acid (IAA), but it has been shown (PubMed:20974893) that this is not the case. It is now admitted (PubMed:22025724 and PubMed:22108406) that the YUCCA family is implicated in the conversion of indole-3-pyruvic acid (IPA) to indole-3-acetic acid (IAA).