Singlet oxygen generation by peroxidases and peroxygenases for chemo-enzymatic synthesis.

Singlet oxygen is a reactive oxygen species undesired in living cells but a rare and valuable reagent in chemical synthesis. We present a fluorescence spectroscopic analysis of the singlet oxygen formation activity of commercial peroxidases and novel peroxygenases. Singlet oxygen sensor green (SOSG) is used as fluorogenic singlet oxygen trap. Establishing a kinetic model for the reaction cascade to the fluorescent SOSG endoperoxide permits a kinetic analysis of enzymatic singlet oxygen formation. All peroxidases and peroxygenases show singlet oxygen formation, no singlet oxygen activity could be found for any catalase under investigation. Substrate inhibition is found for all reactive enzymes. The commercial dye decolorizing peroxidase industrially used for dairy bleaching shows the highest singlet oxygen activity and the lowest inhibition. This enzyme was immobilized on a textile carrier and successfully applied for a chemical synthesis. Here, ascaridole was synthesized via enzymatically produced singlet oxygen.