title: A new generation of flowerlike horseradish peroxides as a nanobiocatalyst for superior enzymatic activity.
abstract: Although various supports including nanomaterials have been widely utilized as platforms for enzymes immobilization in order to enhance their catalytic activities, most of immobilized enzymes exhibited reduced activities compared to free enzymes. In this study, for the first time, we used iron ions (Fe(2+)) and horseradish peroxidase (HRP) enzyme together to synthesize flowerlike hybrid nanostructures with greatly enhanced activity and stability and reported an explanation of the enhancements in both catalytic activity and stability. We demonstrated that Fe(2+)-HRP hybrid nanoflower (HNF) showed catalytic activity of ∼ 512% and ∼ 710%, respectively when stored at +4 °C and room temperature (RT = 20 °C) compared to free HRP. In addition, the HNF stored at +4 °C lost only 2.9% of its original activity within 30 days while the HNF stored at RT lost approximately 10% of its original activity. However, under the same conditions, free HRP enzymes stored at +4 °C and RT lost 68% and 91% of their activities, respectively. We claim that the drastic increases in activities of HNF are associated with to high local HRP concentration in nanoscale dimension, appropriate HRP conformation, less mass transfer limitations, and role of Fe(2+) ion as an activator for HRP. Further biosensors studies based on enhanced activity and stability of HNF are currently underway.
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey; Nanotechnology Research Center, Erciyes University, Kayseri 38039, Turkey. Electronic address: ismailocsoy@erciyes.edu.tr.
authors.forename: Ismail
authors.initials: I
authors.lastname: Ocsoy
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey.
authors.forename: Esra
authors.initials: E
authors.lastname: Dogru
authors.affiliation: Department of Analytical Chemistry, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey.
authors.forename: Seyda
authors.initials: S
authors.lastname: Usta
mesh_terms: D055162:Biocatalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000378:metabolism*; D007501:Iron / Q000737:chemistry / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D004800:Enzymes, Immobilized; D007501:Iron; D006735:Horseradish Peroxidase
keywords: Catalytic activity; HRP; Hybrid nanoflower; Iron ion; Stability