Enzyme-mimic activity of ferric nano-core residing in ferritin and its biosensing applications

Abstract

Ferritins are nanoscale globular protein cages encapsulating a ferric core. They widely exist in animals, plants, and microbes, playing indispensable roles in iron homeostasis. Interestingly, our study clearly demonstrates that ferritin has an enzyme-mimic activity derived from its ferric nanocore but not the protein cage. Further study revealed that the mimic-enzyme activity of ferritin is more thermally stable and pH-tolerant compared with horseradish peroxidase. Considering the abundance of ferritin in numerous organisms, this finding may indicate a new role of ferritin in antioxidant and detoxification metabolisms. In addition, as a natural protein-caged nanoparticle with an enzyme-mimic activity, ferritin is readily conjugated with biomolecules to construct nanobiosensors, thus holds promising potential for facile and biocompatible labeling for sensitive and robust bioassays in biomedical applications. © 2011 American Chemical Society.