Chemical kinetics and interactions involved in horseradish peroxidase-mediated oxidative polymerization of phenolic compounds

Abstract

iv To address the growing need for removing the emerging endocrine disrupting compounds (EDCs), the enzyme-based oxidative coupling reaction is suggested as promising alternative in consideration of its generally high specificity and removal efficiency on treatment of waters containing estrogenic phenolic chemicals.Various factors that affect the reaction rate of oxidative coupling (OXC) reaction of phenolic estrogens catalyzed by Horseradish Peroxidase (HRP) were evaluated in this study. Kinetic parameters were obtained for the removal of phenol as well as natural and synthetic estrogens estrone (E 1 ), 17β-estradiol (E 2 ), estriol (E 3 ), and 17α-ethinylestradiol (EE 2 ). Molecular orbital theory and Autodock software were employed to analyze chemical properties and substrate binding characteristics. It is found that the reactions were first order with respect to phenolic concentration and reaction rate constants (k r ) were determined for phenol, E 3 , E 1 , E 2 and EE 2 (in increasing order). It is also found that oxidative coupling was controlled by enzyme-substrate interactions, not diffusion. Docking simulations show that higher binding energy and shorter binding distance both promote more favorable kinetics. This research is the first to show that the OXC of phenolics is an entropy-driven and enthalpy-retarded process.

Enzymatically Cross-Linked Hyperbranched Polyglycerol Hydrogels as Scaffolds for Living Cells

“…The dependency of network formation on HRP-concentration as illustrated in SI Figures S13 and S14 strongly resembles typical kinetics of enzyme-catalyzed product formation. 40,41 This illustrates that network formation is directly connected to the applied amount of enzyme activity, which is therefore a perfect parameter for controlling gelation time.…”

Kopling Oksidatif Eugenol Menggunakan Ekstrak Enzim Peroksidase dari Akar Tanaman Sawi Hijau serta Uji Bioaktivitasnya

“…Pada dekade terakhir, modifikasi eugenol dilakukan dengan 79 tujuan mensintesis senyawa turunan eugenol dengan struktur molekul baru dan aktivitas biologi yang semakin beragam (Hidalgo et al, 2009;Mikhailovskii, Surikova, Limanskii, & Vakhrin, 2012;Sadeghian, Seyedi, Saberi, Arghiari, & Riazi, 2008). Salah satu tipe reaksi organik untuk memodifikasi senyawa fenolik seperti fenol, eugenol, isoeugenol, katekol, guaiakol dan timol adalah kopling oksidatif dengan bantuan katalis kimia (Barve et al, 2015) maupun biokatalis (Cheng & Harper Jr, 2012).…”

Comprehensive assessment of Cytochrome P450 reactions: A multiplex approach using real-time ESI-MS

“…In order to assess the experimental data, the diffusion-controlled rate of reaction was calculated according to Equation 3 [37,38]. Considering the different assay combinations, the reaction rate of a substrate (S) with an enzyme (E) was determined.…”