PURIFICATION, CHARACTERIZATION AND COMPARISON OF 2 NONHEME BROMOPEROXIDASES FROM STREPTOMYCES-AUREOFACIENS ATCC-10762

Two non-haem bromoperoxidases (BPO 1 and BPO 2) were purified from the 7-chlorotetracycline-producing strain Streptomyces aureofaciens ATCC 10762. Both enzymes showed azide-insensitive brominating activity, and bromide-dependent peroxidase activity. BPO 1 was a dimer (M(r) 65 000) with subunits of identical size (M(r) 31 000). The pI was estimated to be 4.5. The enzyme did not cross-react with antibodies raised against the non-haem bromoperoxidase (M(r) 90 000) from S. aureofaciens Tu24, a strain that also produces 7-chlorotetracycline. The M(r) of BPO 2 was estimated to be 90 000. The enzyme had three identical subunits (M(r) 31 000), and its isoelectric point was 3.5, identical with that of the bromoperoxidase from S. aureofaciens Tu24. Moreover, BPO 2 was immunologically identical with the bromoperoxidase from S. aureofaciens Tu24, although both it and BPO 1 could be distinguished electrophoretically from the latter bromoperoxidase.