In this paper, the reusability and process stability of nano-reengineered horseradish peroxidase was investigated in fluorescence based sensing system for hydrogen peroxide determination as a model application. To this end, dendron macromolecules were attached to enzyme surface through bio-conjugation techniques. The resulted enzyme-polymer nanoparticles, with average size of 14(±2) nm, showed significant life time and thermal stability. For enzyme recovery and reusability purposes, the enzyme-polymer nanoparticles were labelled with magnetic nanoparticles with a labelling yield of 90%. These labelled enzyme molecules showed significant process stability up to 7 recycling period in a model sensing system. A linear calibration curve was obtained over the hydrogen peroxide concentrations ranging from 5×10-8 mol L-1 to 1×10-5 mol L-1 with detection limit of 1.3×10-9 mol L-1 for the sensing system under the optimal conditions.