Transformation products of bisphenol A by a recombinant <i>Trametes villosa</i> laccase and their estrogenic activity

Abstract

Abstract A Trametes villosa laccase, produced as a recombinant protein in Aspergillus oryzae , was purified to an electrophoretically homogeneous state and employed in studies on the metabolism of bisphenol A. Structural analysis of the bisphenol A reaction products by the enzyme indicated that the dimer, trimer, tetramer, pentamer, and hexamer of bisphenol A with CC and/or CO bonds between phenol moieties, were formed as the result of successive oxidative‐condensation. The reaction mixture also contained oligomers fragments, each with phenol molecules, suggesting the occurrence of cleavage of the formed oligomers to release 4‐isopropenylphenol. A luciferase reporter assay using COS‐7 cells revealed that both the soluble and insoluble fractions of the bisphenol A reaction products had no estrogenic activity even at rather high concentrations. Copyright © 2004 Society of Chemical Industry