Oxygenase component of anthranilate dioxygenase multicomponent enzyme system which catalyzes the incorporation of both atoms of molecular oxygen into anthranilate to form catechol. Can also act on benzoate and salicylate but not on 2-chlorobenzoate or o-toluate. anthranilate + 3 H(+) + NADH + O2 = catechol + CO2 + NAD(+) + NH4(+) anthranilate + 3 H(+) + NADPH + O2 = catechol + CO2 + NADP(+) + NH4(+) Aromatic compound metabolism; anthranilate degradation via hydroxylation; catechol from anthranilate: step 1/1. Part of a multicomponent enzyme system composed of a reductase (AndAa), a ferredoxin (AndAb) and a two-subunit oxygenase component (AndAc and AndAd). By anthranilate but not by benzoate or salicylate. Expression is positively regulated by the transcriptional regulator AndR. Belongs to the bacterial ring-hydroxylating dioxygenase beta subunit family.