Selective oxidations using a cytochrome P450 enzyme variant driven with surrogate oxygen donors and light

Abstract

Cytochrome P450 monooxygenase enzymes are versatile catalysts, which have been adapted for multiple applications in chemical synthesis. Mutation of a highly conserved active site threonine to a glutamate can convert these enzymes into peroxygenases that utilise hydrogen peroxide (H2O2). Here, we use the T252E-CYP199A4 variant to study peroxide-driven oxidation activity by using H2O2 and urea-hydrogen peroxide (UHP). We demonstrate that the T252E variant has a higher stability to H2O2 in the presence of substrate that can undergo carbon-hydrogen abstraction. This peroxygenase variant could efficiently catalyse O-demethylation and an enantioselective epoxidation reaction (94 % ee). Neither the monooxygenase nor peroxygenase pathways of the P450 demonstrated a significant kinetic isotope effect (KIE) for the oxidation of deuterated substrates. These new peroxygenase variants offer the possibility of simpler cytochrome P450 systems for selective oxidations. To demonstrate this, a light driven H2O2 generating system was used to support efficient product formation with this peroxygenase enzyme.