Evidence for the existence of PAHquinone reductas

Authors: YongHak Kim Joanna D Moody James P Freeman Barbara Brezna KarlHeinrich Engesser Carl E Cerniglia

Publish Date: 2004/11/11

Volume: 31, Issue: 11, Pages: 507-516

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Abstract

Polycyclic aromatic hydrocarbon PAH quinone reductase PQR and catecholOmethyltransferase COMT from the PAHdegrading Mycobacterium vanbaalenii PYR1 were demonstrated to be constitutive enzymes located in the soluble fraction of cell extracts PQR activities for the reduction of 910phenanthrenequinone and 45pyrene quinone were 140±013 and 012±001 μmol min−1 mgprotein−1 respectively The exogenous catechols alizarin anthrarobin 23dihydroxynaphthalene and esculetin inhibited PQR activity Anthrarobin 100 μM and esculetin 100 μM inhibited 45pyrenequinone reduction by 64–92 COMT was involved in the Omethylation of 12dihydroxyphenanthrene to form 1methoxy2hydroxyphenanthrene and 12dimethoxyphenanthrene Both pyrene and 1hydroxypyrene were metabolized by M vanbaalenii PYR1 to form 1methoxypyrene 1methoxy2hydroxypyrene 1hydroxy2methoxypyrene and 12dimethoxypyrene Among the catechols tested anthrarobin showed the highest COMT activity 106±004 nmol/30 min−1 mgprotein−1 These results suggest that the PQR and COMT activities of M vanbaalenii PYR1 may play an important role in the detoxification of PAH catecholsThe authors thank John B Sutherland for critical review of the manuscript and Diana Mathews for clerical assistance This research was supported by the Postgraduate Research Participation Program at the National Center for Toxicological Research administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the United States Department of Energy and the Food and Drug Administration

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