Monooxygenases incorporate one hydroxyl group into substrates and are found in many metabolic pathways. In this reaction, two atoms of dioxygen are reduced to one hydroxyl group and one H₂O molecule by the concomitant oxidation of NAD(P)H [<cite idref="PUB00000123"/>]. P-hydroxybenzoate hydroxylase from <taxon tax_id="294">Pseudomonas fluorescens</taxon> contains this sequence motif (present in in flavoprotein hydroxylases) with a putative dual function in FAD and NADPH binding [<cite idref="PUB00006431"/>]. Monooxygenase, FAD-binding