title: Evidence for the existence of PAH-quinone reductase and catechol-O-methyltransferase in Mycobacterium vanbaalenii PYR-1.
abstract: Polycyclic aromatic hydrocarbon (PAH) quinone reductase (PQR) and catechol-O-methyltransferase (COMT), from the PAH-degrading Mycobacterium vanbaalenii PYR-1, were demonstrated to be constitutive enzymes located in the soluble fraction of cell extracts. PQR activities for the reduction of 9,10-phenanthrenequinone and 4,5-pyrene- quinone were 1.40+/-0.13 and 0.12+/-0.01 micromol min(-1) mg-protein(-1), respectively. The exogenous catechols alizarin, anthrarobin, 2,3-dihydroxynaphthalene and esculetin inhibited PQR activity. Anthrarobin (100 microM) and esculetin (100 microM) inhibited 4,5-pyrenequinone reduction by 64-92%. COMT was involved in the O-methylation of 1,2-dihydroxyphenanthrene to form 1-methoxy-2-hydroxyphenanthrene and 1,2-dimethoxyphenanthrene. Both pyrene and 1-hydroxypyrene were metabolized by M. vanbaalenii PYR-1 to form 1-methoxypyrene, 1-methoxy-2-hydroxypyrene, 1-hydroxy-2-methoxypyrene and 1,2-dimethoxypyrene. Among the catechols tested, anthrarobin showed the highest COMT activity (1.06+/-0.04 nmol/30 min(-1) mg-protein(-1)). These results suggest that the PQR and COMT activities of M. vanbaalenii PYR-1 may play an important role in the detoxification of PAH catechols.
authors.affiliation: Division of Microbiology, National Center for Toxicological Research, US FDA, 3900 NCTR Rd., Jefferson, AR, 72079, USA.
authors.forename: Yong-Hak
authors.initials: YH
authors.lastname: Kim
authors.forename: Joanna D
authors.initials: JD
authors.lastname: Moody
authors.forename: James P
authors.initials: JP
authors.lastname: Freeman
authors.forename: Barbara
authors.initials: B
authors.lastname: Brezna
authors.forename: Karl-Heinrich
authors.initials: KH
authors.lastname: Engesser
authors.forename: Carl E
authors.initials: CE
authors.lastname: Cerniglia
mesh_terms: D001711:Biotransformation; D002394:Catechol O-Methyltransferase / Q000235:genetics / Q000378:metabolism*; D009161:Mycobacterium / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D011808:Quinone Reductases / Q000096:biosynthesis / Q000145:classification / Q000378:metabolism*
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons; D011808:Quinone Reductases; D002394:Catechol O-Methyltransferase