Molecular Mechanisms Controlling the Rate and Specificity of Catechol O-Methylation by Human Soluble Catechol O-Methyltransferase
- 1 February 2001
- journal article
- Published by Elsevier in Molecular Pharmacology
- Vol. 59 (2) , 393-402
- https://doi.org/10.1124/mol.59.2.393
Abstract
Molecular mechanisms determining the turn-over rate and specificity of catechol O-methylation were studied by combining enzyme kinetic measurements, computational modeling of substrate properties and fitting ligands in a 3D model of the active site of the enzyme. Enzyme kinetic measurements were carried out for 46 compounds, including most clinically used catechol drugs, by using recombinant human soluble catechol O-methyltransferase (COMT). The most important mechanism decreasing the turnover rate and increasing affinity was the electron withdrawing effect of substituents. Several other mechanisms by which substituents affected reactivity and affinity were identified. Highest turnover rates were determined for unsubstituted catechol and pyrogallol. Pyrogallol derivatives generally seemed to be more specific substrates than catechols. Catecholestrogens were the most specific endogenous substrates, whereas catecholamines were rather poor substrates. Among the catechol drugs used in thel-DOPA treatment of Parkinson9s disease, the COMT inhibitors entacapone and tolcapone were not methylated, whereas the DOPA decarboxylase inhibitor benserazide was 15 times more specific substrate than l-DOPA, the target of COMT inhibition. The structure-activity relationships found allow the prediction of reactivity, affinity, and specificity with useful accuracy for catechols with a wide range of structures and properties. The knowledge can be used in the evaluation of metabolic interactions of endogenous catechols, drugs and dietary catechols, and in the designing of drugs with the catechol pharmacophore.Keywords
This publication has 30 references indexed in Scilit:
- QM−FE and Molecular Dynamics Calculations on Catechol O-Methyltransferase: Free Energy of Activation in the Enzyme and in Aqueous Solution and Regioselectivity of the Enzyme-Catalyzed ReactionJournal of the American Chemical Society, 2000
- Importance of Correlated Motions in Forming Highly Reactive Near Attack Conformations in Catechol O-MethyltransferaseJournal of the American Chemical Society, 1998
- A Theoretical Examination of the Factors Controlling the Catalytic Efficiency of a Transmethylation Enzyme: Catechol O-MethyltransferaseJournal of the American Chemical Society, 1997
- Expression and Intracellular Localization of Catechol O‐methyltransferase in Transfected Mammalian CellsEuropean Journal of Biochemistry, 1997
- Kinetics of Human Soluble and Membrane-Bound Catechol O-Methyltransferase: A Revised Mechanism and Description of the Thermolabile Variant of the EnzymeBiochemistry, 1995
- Crystal structure of catechol O-methyltransferaseNature, 1994
- The Effect of Catechol-O-Methyl Transferase Inhibition by Entacapone on the Pharmacokinetics and Metabolism of Levodopa in Healthy VolunteersClinical Neuropharmacology, 1993
- Molecular cloning and characterization of rat liver catechol-O-methyltransferaseGene, 1990
- QSAR and Binding Model for Inhibition of Rat Liver Catechol‐O‐Methyl‐Transferase by 1,5‐Substituted‐3,4‐DihydroxybenzenesQuantitative Structure-Activity Relationships, 1989
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976