Characterization of aromatic dehalogenases of Mycobacterium fortuitum CG-2

Two different dehalogenation enzymes were found in cell extracts of Mycobacterium fortuitum CG-2. The first enzyme was a halophenol para-hydroxylase, a membrane-associated monooxygenase that required molecular oxygen and catalyzed the para-hydroxylation and dehalogenation of chlorinated, fluorinated, and brominated phenols to the corresponding halogenated hydroquinones. The membrane preparation with this activity was inhibited by cytochrome P-450 inhibitors and also showed an increase in the A448 caused by CO. The second enzyme hydroxylated and reductively dehalogenated tetrahalohydroquinones to 1,2,4-trihydroxybenzene. This halohydroquinone-dehalogenating enzyme was soluble, did not require oxygen, and was not inhibited by cytochrome P-450 inhibitors.