Generation of OH radical during enzymatic reduction of 9,10‐anthraquinone‐2‐sulphonate Can semiquinone decompose hydrogen peroxide?

Abstract
Spin-trapping experiments have shown that 9, 10-anthraquinone-2-sulphonate (AQS) can be reduced enzymatically with NADPH-cytochrome P-450 reductase (FP) producing OH radicals. It has been revealed for the first time that the radical anion of AQS cannot decompose H 2 O 2 as indicated by flash-photolysis data. From the experimental results obtained it follows that an enzyme system containing NADPH, AQS and FP produces both accumulation of H 2 O 2 from molecular oxygen and reduction of Fe 3+ to Fe 2+ which decomposes H 2 O 2 catalytically via a Fenton reaction.