Electrochemical generation of ferrylmyoglobin during oxidation of styrene with films of DNA and a poly (ester sulfonic acid) ionomer

The chemistry of electrochemically-driven myoglobin-catalyzed oxidation of styrene was investigated in films of DNA or Eastman AQ ionomer on optically transparent electrodes. Conversion of styrene to styrene oxide proceeded v ia a ferrylmyoglobin radical intermediate. Ferrylmyoglobins were clearly de tected by spectroelectrochemistry in films of 1-4 mm thick. The ferrylmyogl obin radical is produced by reaction of metmyoglobin (Mb) in the films with hydrogen peroxide formed by electrochemical catalytic reduction of oxygen catalyzed by Mb. Thus, electrochemically-driven styrene oxidation with thes e films proceeds by a 'doubly catalytic' electrode-driven reduction-oxidati on pathway. Ferrylmyoglobin formation during electrolysis of Mb-DNA films i n aerobic solutions was much faster, and styrene oxidation occurred with le ss Mb decomposition compared to the Mb-AQ films. The better performance of Mb-DNA films is correlated with a larger fraction of electroactive Mb and b etter stability than for the Mb-AQ films. (C) 1999 Elsevier Science B.V. Al l rights reserved.