TRANSFORMATION OF PHENANTHRENE IN ENZYME-MEDIATOR-SUBSTRATE SYSTEMS BY USING QUERCETIN AS METABOLIC MEDIATOR

Abstract

The removal mechanism of aromatic polycyclic hydrocarbons in phytoremediation processes are still uncertain. Previous studies suggested that metabolic mediators could participate in this process by forming enzyme-mediator-substrate complexes, where the mediator are small molecules derived from plant secondary metabolism that interact molecularly with the contaminant. The aim of this work was to investigate whether quercetin can act as metabolic mediators in the transformation of phenanthrene in the presence and absence of radish peroxidase as model enzyme. The results from the phenanthrene reactions with quercetin in the presence and absence of radish peroxidase showed 85% transformation of phenanthrene (50 μM). These results suggest that participation of peroxidase is not essential for the phenanthrene removal process, nevertheless under these conditions the rate of transformation might be regulated by the H2O2 concentration. Further, the transformation products suggest that the in vitro removal process, with and without enzyme, was a sequential oxidation of the molecule mediated by quercetin and stimulated by the presence of H2O2