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OXIDATIVE, REDUCTIVE,

AND HYDROLYTIC METABOLISM

OF DRUGS

F. PETERGUENGERICH

2.1 INTRODUCTION

Oxidation, reduction, and hydrolysis reactions are common in the metabolism of
drugs. In this chapter, each of these three types of chemistry will be treated briefly,
with further division regarding individual enzymes. The analysis is brief. For
more information about these enzymes, an older reference (Guengerich, 1997)
covers each (plus the conjugation enzymes); in some cases more recent
monographs are available, for example, for P450 (Ortiz de Montellano, 2005).

2.2 NOMENCLATURE AND TERMINOLOGY

Almost all of the enzymes to be discussed here exist in multigene families of
varying complexity. These enzymes will be treated in a rather generic manner,
with only reference to specific enzymes as examples or to specific reactions. With
almost all of the enzymes under consideration, the individual genes and proteins
are organized into specific families using a system of letters and numbers. The use
of the terms ‘‘isozymes’’ and ‘‘isoforms’’ is no longer encouraged in that these are
simply distinct ‘‘enzymes’’ that are organized into large gene families. Isozymes,
by definition, catalyze the same reaction. With most of the systems under
consideration here, the emphasis is on selectivity toward different reactions.

Drug Metabolism in Drug Design and Development, Edited by Donglu Zhang, Mingshe Zhu
and W. Griffith Humphreys
Copyright#2008 John Wiley & Sons, Inc.

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