Nanozymes with reductase-like activities: antioxidant properties and electrochemical behavior.

Nanozymes (NZs) as stable cost-effective mimics of natural enzymes may be promising catalysts in food and environmental biotechnology, biosensors, alternative energy and medicine. The majority of known NZs are mimetics of oxidoreductases, although there are only limited data regarding mimetics of reductases. In the present research, a number of metal-based NZs were synthesized via chemical methods and screened for their antioxidant ability in solution. The most effective reductase-like Zn/Cd/Cu NZ was characterized in detail. Its antioxidant properties in comparison with several food products and Trolox, as well as substrate specificity, size and composition were studied. Zn/Cd/Cu NZ was shown to mimic preferentially selenite reductase. The amperometric sensor was constructed possessing a high sensitivity (1700 A M -1 m -2 ) and a broad linear range (16-1000 μM) for selenite ions. The possibility to apply the fabricated sensor for selenite determination in commercial mineral water has been demonstrated.