Part of a multicomponent enzyme which catalyzes the degradation of phenol and some of its methylated derivatives (PubMed:2254259). DmpL, DmpN and DmpO form the oxygenase component of the complex (PubMed:12186554). Required for growth on phenol and for in vitro phenol hydroxylase activity (PubMed:2254258, PubMed:2254259). H(+) + NADH + O2 + phenol = catechol + H2O + NAD(+) Binds 2 Fe(2+) ions per subunit. Requires DmpM for efficient turnover. The activity of DmpLNO oxygenase is inhibited by dithiothreitol (DTT) by a mechanism apparently involving H(2)O(2) generation. Aromatic compound metabolism; phenol degradation. The multicomponent enzyme phenol hydroxylase is formed by DmpL (P1 component), DmpM (P2 component), DmpN (P3 component), DmpO (P4 component) and DmpP (P5 component) (PubMed:2254259). The oxygenase component is a dimer composed of three subunits, DmpL, DmpN and DmpO (DmpLNO) (PubMed:12186554). DmpN interacts with the auxiliary protein DmpK (P0 component) (PubMed:8995386). Cells lacking this gene cannot grow on phenol. Belongs to the TmoA/XamoA family.