Axial Ligand Effect On The Rate Constant of Aromatic Hydroxylation By Iron(IV)–Oxo Complexes Mimicking Cytochrome P450 Enzymes

2011 ◽  
Vol 116 (1) ◽  
pp. 718-730 ◽  
Author(s):  
Devesh Kumar ◽  
G. Narahari Sastry ◽  
Sam P. de Visser
Keyword(s):  
Cytochrome P450 ◽  
Rate Constant ◽  
Axial Ligand ◽  
Cytochrome P450 Enzymes ◽  
Ligand Effect ◽  
Oxo Complexes ◽  
Aromatic Hydroxylation

The intrinsic axial ligand effect on propene oxidation by horseradish peroxidase versus cytochrome P450 enzymes

2005 ◽  
Vol 10 (2) ◽  
pp. 181-189 ◽  
Author(s):  
Devesh Kumar ◽  
Sam P. de Visser ◽  
Pankaz K. Sharma ◽  
Etienne Derat ◽  
Sason Shaik
Keyword(s):  
Cytochrome P450 ◽  
Horseradish Peroxidase ◽  
Axial Ligand ◽  
Cytochrome P450 Enzymes ◽  
Ligand Effect ◽  
Propene Oxidation

pH Changes That Induce an Axial Ligand Effect on Nonheme Iron(IV) Oxo Complexes with an Appended Aminopropyl Functionality

2021 ◽  
Author(s):  
Reza Latifi ◽  
Taryn D. Palluccio ◽  
Wanhua Ye ◽  
Jennifer L. Minnick ◽  
Kwame S. Glinton ◽  
...  
Keyword(s):  
Axial Ligand ◽  
Nonheme Iron ◽  
Ligand Effect ◽  
Ph Changes ◽  
Oxo Complexes

scholarly journals Characterization of O-demethylations and Aromatic Hydroxylations Mediated by Cytochromes P450 in the Metabolism of Flavonoid Aglycons

2019 ◽  
Vol 92 (1) ◽  
pp. 115-123 ◽  
Author(s):  
Goran Benković ◽  
Hrvoje Rimac ◽  
Željan Maleš ◽  
Siniša Tomić ◽  
Zoran Lončar ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Human Liver ◽  
Cytochromes P450 ◽  
Liver Microsomes ◽  
Cytochrome P450 Enzymes ◽  
Uv Detector ◽  
Aromatic Hydroxylation ◽  
Metabolism Of Xenobiotics ◽  
Kinetics Of

One of the most important groups of metabolic enzymes is cytochrome P450 superfamily. These enzymes are important in terms of the catalytic diversity and the large number of xenobiotics that are detoxified or activated by converting to reactive metabolites. Flavonoids are xenobiotics to which humans are exposed through diet. Data on their oxidative metabolism mediated by cytochromes P450 are limited. The aim of this study was to determine the enzymatic kinetics of O-demethylation and aromatic hydroxylation of flavonoid aglycons on recombinant cytochrome P450 enzymes and human liver microsomes systems. The study was performed on ten flavonoids, namely 3,7-dihydroxyflavone, 7-hydroxyflavone, acacetin, apigenin, flavone, galangin, kaempferol, naringenin, sakuranetin, and tangeretin using liquid chromatography coupled with mass spectrometry and UV detector. Most relevant enzyme involved in metabolism of flavonoid aglycons is CYP1A2, and its catalytic effectiveness ranges from 0.5 to 2.9 × 106 M–1 min–1. Having in mind high expression and involvement of CYP1A2 in metabolism of xenobiotics including drugs, and its intraindividual differences in expression and activity, potential of drug-flavonoid competitive interactions/inhibitions should be considered when consuming dietary supplement and foods rich in flavonoids.

AN ANALYSIS OF THE REGIOSELECTIVITY OF AROMATIC HYDROXYLATION AND N-OXYGENATION BY CYTOCHROME P450 ENZYMES

2004 ◽  
Vol 32 (3) ◽  
pp. 328-332 ◽  
Author(s):  
Tamara S. Dowers ◽  
Dan A. Rock ◽  
Denise A. Rock ◽  
Brandon N. S. Perkins ◽  
Jeffery P. Jones
Keyword(s):  
Cytochrome P450 ◽  
Cytochrome P450 Enzymes ◽  
Aromatic Hydroxylation

scholarly journals Sequential Measurements of Catalytic Activities of Multi-Drug-Resistance Transporters and Cytochrome P450 Enzymes by Cytometry of Reaction Rate Constant

2020 ◽  
Author(s):  
Vasilij Koshkin ◽  
Mariana Bleker de Oliveira ◽  
Sven Kochmann ◽  
Chun Peng ◽  
Sergey N. Krylov
Keyword(s):  
Drug Resistance ◽  
Cytochrome P450 ◽  
Rate Constant ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Population Heterogeneity ◽  
Multi Drug Resistance ◽  
Specific Substrate ◽  
Cytochrome P450 Enzymes ◽  
Sequential Measurements

ABSTRACTCytometry of reaction rate constant (CRRC) is an accurate and robust approach to characterize cell-population heterogeneity using rate constants of cellular processes for which kinetic mechanisms are known. We work on a CRRC-based method to develop predictors of tumor chemoresistance driven by two processes: drug extrusion by multi-drug-resistance (MDR) transporters and drug inactivation by cytochrome-P450 enzymes (CYP). Each of the two possess is studied with its specific substrate and the process activity is characterized by a corresponding unimolecular rate constant. Due to the incompatibility of MDR and CYP assays, MDR and CYP activities may be difficult to measure simultaneously suggesting that they may need to be measured sequentially. The sequential measurements may also impose a problem: the results of the second assay may be affected by artifacts exerted by the first assay. The goal of this work was to understand whether the cells have a memory of the first assay that significantly affects the results of the second assay. To achieve this goal, we compared CRRC results for two orders of sequential measurements: the MDR→CYP order in which MDR activity is measured before CYP activity and the CYP→MDR order in which CYP activity is measured before MDR activity. It was found that the results of the CYP assay were similar in both orders; on the contrary, the results of the MDR assay were significantly different. Our findings suggest that MDR and CYP activity can be studied sequentially provided that MDR activity is measured first and CYP activity second.

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