Oxygenase required for conversion of tetracenomycin F1 to tetracenomycin D3. O2 + tetracenomycin F1 = H(+) + H2O + tetracenomycin D3 Inhibited by p-chloromercuribenzoic acid, N-ethylmaleimide and diethyl pyrocarbonate. Optimum pH is 7.5. Antibiotic biosynthesis; tetracenomycin C biosynthesis. Homotrimer.