Electrochemical and mARC‐Catalyzed Enzymatic Reduction of para‐Substituted Benzamidoximes: Consequences for the Prodrug Concept “Amidoximes instead of Amidines” |
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Authors: | Eva Bauch Dr. Debora Reichmann Prof. Dr. Ralf‐Rainer Mendel Dr. Florian Bittner Anne‐Marie Manke Prof. Dr. Philipp Kurz Dr. Ulrich Girreser Dr. Antje Havemeyer Prof. Dr. Bernd Clement |
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Affiliation: | 1. Department of Pharmaceutical and Medicinal Chemistry, Christian Albrechts University Kiel, Gutenbergstra?e 76, 24118 Kiel (Germany);2. Department of Plant Biology, Technical University Braunschweig, Humboldtstra?e 1, 38106 Braunschweig (Germany);3. Institute for Inorganic and Analytical Chemistry, Albert Ludwigs University Freiburg, Albertstra?e 21, 79104 Freiburg (Germany) |
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Abstract: | The mitochondrial amidoxime reducing component (mARC) activates amidoxime prodrugs by reduction to the corresponding amidine drugs. This study analyzes relationships between the chemical structure of the prodrug and its metabolic activation and compares its enzyme‐mediated vs. electrochemical reduction. The enzyme kinetic parameters KM and Vmax for the N‐reduction of ten para‐substituted derivatives of the model compound benzamidoxime were determined by incubation with recombinant proteins and subcellular fractions from pig liver followed by quantification of the metabolites by HPLC. A clear influence of the substituents at position 4 on the chemical properties of the amidoxime function was confirmed by correlation analyses of 1H NMR chemical shifts and the redox potentials of the 4‐substituted benzamidoximes with Hammett’s σ. However, no clear relationship between the kinetic parameters for the enzymatic reduction and Hammett’s σ or the lipophilicity could be found. It is thus concluded that these properties as well as the redox potential of the amidoxime can be largely ignored during the development of new amidoxime prodrugs, at least regarding prodrug activation. |
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Keywords: | amidoximes biotransformation enzyme catalysis molybdenum cofactor prodrugs |
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