Investigation of cytochrome P450-modified cadmium sulfide quantum dots as photocatalysts

Cadmium sulfide quantum dots modified with the enzyme cytochrome P450 CYP152A1 were investigated to evaluate the potential of these nanohybrids as photoactivated catalysts. The quantum dots produce reactive oxygen radicals upon irradiation and these radicals are used by the CYP152A1 enzyme to catalyze the hydroxylation of myristic acid. We here explore the effects of the relative stoichiometry of enzyme and quantum dots on the activity of the nanohybrids as well as the stability of the nanohybrid and of the enzyme towards several damaging factors such as UV light, hydrogen peroxide, and heat. We found that the enzymatic activity is greatly decreased after long exposure to UV light. We also demonstrated the possibility of using pre-irradiated quantum dots to perform chemical transformations. Based on these findings, it was possible to optimize the nanohybrid composition as well as the reaction conditions in order to maintain the catalytic activity of the enzyme in the nanohybrids. Finally, we showed that it was possible to control the photocatalytic activity of the nanohybrids by simply switching on and off the UV light.