Horseradish peroxidase catalyzed and electrochemical oxidations of 2-thiouracil — A comparison

Abstract

463-468Horseradish peroxidase (type VIII) catalyzed and electrochemical oxidations of 2-thiouracil have been studied in phosphate buffer of pH 7.20 (μ==1.0 M) at an ambient temperature of 25±2°C. The peroxidase catalyzed oxidation has been initiated by using hydrogen peroxide and electrooxidation carried out at pyrolytic graphite electrode. The UV-absorbing intermediates generated in both the oxidations have been characterized by voltammetry, spectrophotometry and by kinetics of decay and are found identical. Products of enzymic and electrochemical oxidations have been characterized by using GCMS stuides. A tentative redox scheme has been proposed for the enzymic oxidation of 2-thiouracil and compared with that of electrooxidation and has also been found similar. Thus, it has been concluded that oxidation of 2-thiouracil by enzymic and electrochemical methods are, in a chemical sense, identical