Construction of pH sensitive artificial glutathione peroxidase based on the formation and dissociation of molecular machine

Glutathione peroxidase (GPx) is an antioxidant enzyme in vivo. For expanding the application of GPx in vitro, imitating GPx functions has aroused great interest. The pH-sensitive GPx artificial enzymes that utilize natural pH differences in living organisms to achieve responses have a wide range of potential applications. However, up to now, the activities of pH sensitive GPx mimics are relatively low. Thus, organic tellurium compound I, which contains high activity catalytic center of glutathione peroxidase (GPx) and two primary amine groups, was designed and synthesized in this research. The enzymatic reaction kinetics measurement results demonstrated that the second order reaction rate constant of compound I was at the level of as high as 101 L·mol-1·min-1. Compound I formed molecular machine with CB[6] at pH=6. In this case, only (0.04±0.02) μmol·min-1·μmol-1GPx activity was shown as the active site was encapsulated into CB[6] and thereby cannot bind substrate. Molecular machine was partly dissociation when only one of the two primary amine groups was protonated at pH=7. In this case, (0.35±0.06) μmol·min-1·μmol-1GPx activity was shown as the active site gradually exposed to solution. The high activity pH sensitive artificial glutathione peroxidase was constructed through the formation and partly dissociation of molecular machine formed by compound I and CB[6] by changing pH between 6 and 7. © 2022 Chemical Industry Press. All rights reserved.