A Simple Approach for Pilot Analysis of Time-dependent Enzyme Inhibition: Discrimination Between Mechanism-based Inactivation and Tight Binding Inhibitor Behavior
Open Access
- 1 April 2020
- journal article
- Published by Institute of Biochemistry in Biomedical Chemistry: Research and Methods
- Vol. 3 (1), e00115
- https://doi.org/10.18097/bmcrm00115
Abstract
The increase in enzyme inhibition developed during prolonged incubation of an enzyme preparation with a chemical substance may be associated with both the non-covalent and also with covalent enzyme-inhibitor complex formation. The latter case involves catalytic conversion of a mechanism-based irreversible inhibitor (a poor substrate) into a reactive species forming covalent adduct(s) with the enzyme and thus irreversibly inactivating the enzyme molecule. Using a simple approach, based on comparison of enzyme inhibition after preincubation with a potential inhibitor at 4ºC or 37ºC we have analyzed inhibition of monoamine oxidase A (MAO A) by known MAO inhibitors pargyline and pirlindole (pyrazidol). MAO A inhibitory activity of pirlindole (reversible tight binding inhibitor of MAO A) assayed after mitochondrial wash was basically the same for the incubation at both 4ºC and 37ºC. In contrast to pirlindole, the effect of pargyline (mechanism based irreversible MAO inhibitor) strongly depended on the temperature of the incubation medium. At 37ºC the residual activity MAO A in the mitochondrial fraction after washing was significantly lower than in the mitochondrial samples incubated with pargyline at 4ºC. Results of this study suggest that using analysis of both time- and temperature-dependence of inhibition it is possible to discriminate mechanism-based irreversible inhibition and reversible tight binding inhibition of target enzymKeywords
This publication has 8 references indexed in Scilit:
- Dietary Restrictions and Drug Interactions With Monoamine Oxidase InhibitorsBritish Journal of Psychology, 2012
- Pirlindole in the Treatment of DepressionClinical Drug Investigation, 2011
- Mechanism-Based Inhibition: Deriving KI and kinact Directly from Time-Dependent IC50 ValuesSLAS Discovery, 2009
- The therapeutic potential of monoamine oxidase inhibitorsNature Reviews Neuroscience, 2006
- Inhibition of Monoamine Oxidase by Pirlindole Analogues: 3D-QSAR and CoMFA AnalysisJournal of Chemical Information and Computer Sciences, 1998
- Monoamine oxidase inhibition by novel antidepressant tetrindoleBiochemical Pharmacology, 1994
- Estimation of monoamine oxidase concentrations in soluble and membrane-bound preparations by inhibitor bindingPublished by Springer Science and Business Media LLC ,1994
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976