Mechanism of aromatic hydroxylation in fungi. Evidence for the formation of arene oxides

Abstract

Aromatic and aliphatic hydroxylations as well as O-demethylations occurred during metabolism of aromatic substrates by a range of fungi. para-Hydroxylation of monosubstituted aryl rings by fungi proceeded with migration and retention of deuterium label (NIH shift) and appeared to involve only arene 3,4-oxide intermediates, in common with plant and animal metabolism. The possibility of contributions from arene 1,2- or 2,3-oxide intermediates during ortho-hydroxylation is examined in the light of the results of oxygen-18 incorporation, the lack of deuterium–hydrogen primary kinetic isotope effects, and the wide range of deuterium migration and retention values. From these last experimental data no evidence for an arene oxide isomerase enzyme was found.