Contains Fe2+ or Mn2+ . This enzyme participates in the degradation pathway of biphenyl and PCB (poly chlorinated biphenyls), and catalyses the first ring cleavage step by incorporating two oxygen atoms into the catechol ring formed by EC 18.104.22.168, cis-2,3-dihydrobiphenyl-2,3-diol dehydrogenase.The enzyme from the bacterium Burkholderia xenovorans LB400 can also process catechol, 3-methylcatechol, and 4-methylcatechol, but less efficiently . The enzyme from the carbazole-degrader Pseudomonas resinovorans strain CA10 also accepts 2'-aminobiphenyl-2,3-diol . The enzyme from Ralstonia sp. SBUG 290 can also accept 1,2-dihydroxydibenzofuran and 1,2-dihydroxynaphthalene . The enzyme is strongly inhibited by the substrate .Not identical with EC 22.214.171.124 catechol 2,3-dioxygenase.