Acting on paired donors, with incorporation or reduction of molecular oxygen;
With reduced flavin or flavoprotein as one donor, and incorporation of one atom of oxygen into the other donor
The enzyme catalyses the ortho-hydroxylation of simple phenols into the corresponding catechols. It accepts 4-methylphenol, 4-chlorophenol, and 4-fluorophenol  as well as 4-nitrophenol, 3-nitrophenol, and resorcinol . The enzyme is part of a two-component system that also includes an NADH-dependent flavin reductase. It is strictly dependent on FADH2 and does not accept FMNH2 [1,3]. cf. EC 22.214.171.124, phenol 2-monooxygenase (NADPH).