Possible involvement of toluene-2,3-dioxygenase in defluorination of 3-fluoro-substituted benzenes by toluene-degrading Pseudomonas sp. strain T-12

Abstract

Pseudomonas sp. strain T-12 cells in which the toluene-degradative pathway enzymes have been induced can transform many 3-fluoro-substituted benzenes to the corresponding 2,3-catechols with simultaneous elimination of the fluorine substituent as inorganic fluoride. Substrates for this transformation included 3-fluorotoluene, 3-fluorotrifluorotoluence, 3-fluorohalobenzenes, 3-fluoroanisole, and 3-fluorobenzonitrile. While 3-fluorotoluene and 3-fluoroanisole produced only defluorinated catechols, other substrates generated catechol products with and without the fluorine substituent. The steric size of the C-1 substituent affected the ratio of defluorinated to fluorinated catechols formed from a substrate. A mechanism for the defluorination reaction involving toluene-2,3-dioxygenase is proposed.