H(+) + NADH + O2 + phthalate = cis-4,5-dihydroxycyclohexa-2,6-diene-1,2-dicarboxylate + NAD(+) Binds 1 [2Fe-2S] cluster. Binds 1 Fe cation. Xenobiotic degradation; phthalate degradation; 3,4-dihydroxybenzoate from phthalate: step 1/3. This dioxygenase system consists of two proteins: phthalate oxygenase and phthalate oxygenase reductase. Induced by phthalate and repressed by glucose. Belongs to the bacterial ring-hydroxylating dioxygenase alpha subunit family.