The oxidation of indole derivatives catalyzed by horseradish peroxidase ishighly chemiluminescent

The indole moeity is present in many substances of biological occurrence. I ts metabolism, in most cases, involves an oxidative pathway. This study rep orts the oxidation of a series of indole derivatives, including several of biological origin, catalyzed by horseradish peroxidase in the presence of H 2O2. Chemiluminescence emission was observed in most cases and its intensit y and spectral characteristics were correlated with structural features of the substrates. The structures of the main products were determined. The pa rticipation of molecular oxygen and superoxide ion in the reaction was demo nstrated and a general mechanism for product formation proposed. Since the oxidation of 2-methylindole proved to be highly chemiluminescent, its poten tiality as a developing system for peroxidase-based assays was tested and s howed to be very effective. (C) 2001 Academic Press.