Kinetics of inhibition of peroxidase activity of myeloperoxidase by quercetin |
| |
Authors: | Tatjana Momić Zoran Vujčić Vesna Vasić |
| |
Institution: | 1. Department of Physical Chemistry, Vinča Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade, Republic of Serbia;2. Faculty of Chemistry, University of Belgrade, P.O.Box 158, 11001 Belgrade, Republic of Serbia |
| |
Abstract: | The inhibition of myeloperoxidase (MPO), isolated from human neutrophils, by quercetin was investigated by following peroxidase activity of the enzyme using o-dianisidine as the substrate. The inhibition parameters (IC50) were obtained by graphical analysis of the inhibition curves. A reaction mechanism, which involved the enzyme inhibition by quercetin and H2O2 in excess, was proposed. The rate and equilibrium constants for the proposed reaction path were calculated from experimental data. Kinetic analysis in noninhibiting H2O2 concentration range in the absence and the presence of quercetin revealed that the reaction mechanism underwent Michaelis–Menten kinetics. K and V values indicated that quercetin was a mixed inhibitor of MPO activity. The initial reaction rates were recalculated using the obtained results. Calculated curves fitted the experimental results within the range of experimental error. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 384–394, 2008 |
| |
Keywords: | |
|
|