Inhibition of 2,4-Dichlorophenoxyacetic Acid to Catalase Immobilized on Hierarchical Porous Calcium Phosphate: Kinetic Aspect and Electrochemical Biosensor Construction

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• 作者：Fengping Liu ; Aiming Zhong ; Qin Xu ; Hongen Cao ; Xiaoya Hu
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：July 28, 2016
• 年：2016
• 卷：120
• 期：29
• 页码：15966-15975
• 全文大小：552K
• 年卷期：0
• ISSN：1932-7455

文摘

The inhibition mechanism of 2,4-dichlorophenoxyacetic acid (2,4-D) to catalase was studied by a catalase biosensor in a flow-injection analysis (FIA) system. This system provides an ideal sensing platform to electrochemically evaluate the chemical mechanism of enzyme inhibition. Hierarchical porous calcium phosphate (hp-CaP), as a biocompatible nanomaterial, was used to immobilize catalase for repeat use. 2,4-D together with H₂O₂ was injected into the bioreactor of the immobilized catalase-FIA system during the experimental procedure. The activity of the immobilized catalase was inhibited, which caused a decrease of the catalase-catalyzed H₂O₂ reduction current. Lineweaver–Burk, Dixon, and Cornish–Bowden plots confirmed that the inhibition of catalase by 2,4-D followed an competitive mechanism with a inhibition constant of 4.78 × 10^–7 M. Based on this inhibition characters, a biosensor for 2,4-D detection was constructed. This biosensor showed a linear range from 0.03 to 3.00 μM with a detection limit of 0.015 μM. It demonstrated good stability, acceptable reproducibility and low cost for 2,4-D screening. It has been successfully applied for the determination of 2,4-D in commercial bean sprouts samples. It is anticipated that a rapid evaluation of the chemical mechanism of catalase inhibition by the FIA system could pave the way to rationally designing biosensors.