title: Inhibition mechanism of Tb(III) on horseradish peroxidase activity.
abstract: The inhibition mechanism of Tb(III) on horseradish peroxidase (HRP) in vitro was discussed. The results from MALDI-TOF/MS and X-ray photoelectron spectroscopy (XPS) showed that Tb(III) mainly interacts with the O-containing groups of the amides in the polypeptide chains of the HRP molecules and forms the complex of Tb(III)-HRP, and, in the complex, the molar ratio Tb(III)/HRP is 2 : 1. The results from CD and atomic force microscopy (AFM) indicated that the coordination effect between Tb(III) and HRP can lead to the conformation change in the HRP molecule, in which the contents of alpha-helix and beta-sheet conformation in the peptide of the HRP molecules is decreased, and the content of the random coil conformation is increased. Meanwhile, the coordination effect also leads to the decrease in the content of inter- and intrapeptide-chain H-bonds in the HRP molecules, resulting in the HRP molecular looseness and/or aggregation. Thus, the conformation change in the HRP molecules can significantly decrease the electrochemical reaction of HRP and its electrocatalytic activity for the reduction of H2O2.
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, P. R. China (phone: +86-25-83598031; fax: +86-25-83716813).|The Key Laboratory of Industry Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China.
authors.forename: Shaofen
authors.initials: S
authors.lastname: Guo
authors.affiliation: The Key Laboratory of Industry Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, P. R. China (phone: +86-25-83598031; fax: +86-25-83716813).|The Key Laboratory of Industry Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, P. R. China.|Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China.
authors.forename: Tianhong
authors.initials: T
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Science and Biotechnology, Tsinghua University, Beijing 100084, P. R. China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Ding
authors.affiliation: Jiangsu Key Laboratory of Biofunctional Materials, College of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097, P. R. China (phone: +86-25-83598031; fax: +86-25-83716813).
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Huang
mesh_terms: D031215:Armoracia / Q000201:enzymology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006735:Horseradish Peroxidase / Q000037:antagonists & inhibitors*; D006860:Hydrogen Bonding; D006861:Hydrogen Peroxide / Q000737:chemistry; D010084:Oxidation-Reduction; D011485:Protein Binding; D013725:Terbium / Q000494:pharmacology*; D013816:Thermodynamics
chemical_list: D004791:Enzyme Inhibitors; D013725:Terbium; C067490:terbium chloride; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase