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Inhibition Mechanism of Tb III on Horseradish Peroxidase Activity
Author(s) -
Guo Shaofen,
Zhou Qing,
Lu Tianhong,
Ding Xiaolan,
Huang Xiaohua
Publication year - 2008
Publication title -
chemistry and biodiversity
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 70
eISSN - 1612-1880
pISSN - 1612-1872
DOI - 10.1002/cbdv.200890187
Subject(s) - chemistry , horseradish peroxidase , molecule , random coil , crystallography , x ray photoelectron spectroscopy , stereochemistry , circular dichroism , enzyme , biochemistry , organic chemistry , nuclear magnetic resonance , physics
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 α ‐helix and β ‐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 H 2 O 2 .