PURIFICATION AND CHARACTERIZATION OF 4 CATECHOL 1,2-DIOXYGENASE ISOZYMES FROM THE BENZAMIDE-ASSIMILATING BACTERIUM ARTHROBACTER SPECIES BA-5-17

When Arthrobacter sp. BA-5-17 was grown on benzamide, the bacterium sy nthesized four different catechol 1,2-dioxygenase (CD, EC 1.13.11.1) i sozymes (CD-I, II, III-1, and III-2). We purified each CD to homogenei ty by a series of column chromatography. The molecular masses of the f our CDs were between 68 and 72 kDa. The enzymes were made up of two id entical subunits each with the molecular mass of 33 kDa. CD-I and II w ere indistinguishable in enzymatic properties tested. Most properties of CD-III-1 were similar to those of CD-III-2. However, CD-III-1 had a marked adsorption peak at 325 nm, which disappeared in CD-III-2 as we ll as in CD-I and II. CD-III-1 and III-2 were much more resistant to h eating and inhibitors than CD-I and II.