Component of the terephthalate 1,2-dioxygenase multicomponent enzyme system which catalyzes the dioxygenation of terephthalate (TER/TPA) to 1,2-dihydroxy-3,5-cyclohexadiene-1,4-dicarboxylic acid (DCD). It can also use 2,5-dicarboxypyridine (PDC) and 1,4-napthalenedicarboxylic acid (NDC) as substrates, and preferentially uses NADPH which is the physiological electron donor. H(+) + NADH + O2 + terephthalate = (3S,4R)-3,4-dihydroxycyclohexa-1,5-diene-1,4-dicarboxylate + NAD(+) Inhibited by EDTA. Optimum pH is 7. About 20% of maximum TPADO activity is observed at pH 9, whereas no activity is observed at pH 5. Optimum temperature is 30 degrees Celsius. Approximately 60% of maximum TPADO activity is observed at 15 degrees Celsius, and activity is completely lost at 50 degrees Celsius. Heterotetramer composed of 2 alpha (TphA2I and TphA2II) and 2 beta (TphA3I and TphA3II) subunits. Part of a multicomponent enzyme system composed of a reductase (TphA1I or TphA1II) and a two-subunit oxygenase component (TphA2I or TphA2II and TphA3I or TphA3II). Belongs to the bacterial ring-hydroxylating dioxygenase beta subunit family.