Photoregulating Catalytic Activity of Cyclodextrin-Based Artificial Glutathione Peroxidase by Charged Azobenzene

Abstract

Modulating the activities of enzymes by using an external signal is widely used for many applications. In this paper, it has been performed for the first time that photoregulating the activity of artificial glutathione peroxidase (GPx) by using photocontrolled inclusion–exclusion reaction of the azobenzene with two typical GPx mimics, the telluride β-Cyclodextrin (β-CD) dimmer and the ditelluride β-CD dimmer. The activities of both mimics were differently inhibited by either cationic or anionic azobenzene, owing to the catalytic capacity variance of the telluride moieties of the mimics and the different strength of the electrostatic interactions between the charges of the substrates and the azobenzenes. The inclusion of the anionic azobenzene with the ditelluride β-CD dimmer represented the largest inhibition rate. When the inclusion was irradiated upon UV light, the activity recovered, whereas inhibited again upon visible light. Such process could be repeated many times and a switchable artificial enzyme based on the reaction was proposed. It was performed that photoregulating artificial enzyme by using photocontroled inclusion-exclusion reaction of one 6-ditellurium β-CD dimmer with two anionic azobenzenes. When inclusion underwent the activity of the artificial enzyme was inhibited. After irradiation with UV light, the cis-isomer azobenzene formed, and went away from the cavity left an appropriate cavity for accommodating a substrate, as a result, the activity recovered. After irradiation with visible light, the activity was inhibited over again, owing to that the trans-isomer azobenzene regenerated, and regressed to the inclusion. Such process could be repeated many times.