Component of anthranilate dioxygenase multicomponent enzyme system which catalyzes the incorporation of both atoms of molecular oxygen into anthranilate to form catechol. anthranilate + 3 H(+) + NADH + O2 = catechol + CO2 + NAD(+) + NH4(+) anthranilate + 3 H(+) + NADPH + O2 = catechol + CO2 + NADP(+) + NH4(+) Binds 1 Fe cation per subunit. Binds 1 [2Fe-2S] cluster per subunit. KM values measured using the AntAB complex. Optimum pH is 6.3 for the reverse reaction. E(0) is -86 +/-10 mV for Rieske center at pH 7.0. Aromatic compound metabolism; anthranilate degradation via hydroxylation; catechol from anthranilate: step 1/1. The anthranilate dioxygenase (AntDO) multicomponent enzyme system is composed of an oxygenase component and a NADH:acceptor reductase component (AntC). The oxygenase component is a heterohexamer of 3 large (AntA) and 3 small (AntB) subunits. By anthranilate. Belongs to the bacterial ring-hydroxylating dioxygenase alpha subunit family.