Chapter 7

Metabolism or Degradation of Pesticides: Phase I and Phase II Reactions

Dileep K. Singh

Abstract

In this chapter pesticide metabolism has been described. Pesticide Metabolism is typically a two stage process. These are Phase I and Phase II reactions. Phase I reactions normally add a functional (polar reactive) group to the foreign molecule which enables the phase 2 reaction to take place. These reactions are catalyzed by the cytochrome P450 group of enzymes and other enzymes which are associated with endoplasmic reticulum. Phase I reactions includes, Microsomal oxidation and Extramicrosomal oxidation reactions. Phase II reactions are conjugation reactions and involve the covalent linkage of the toxin or phase I product to a polar compound. In general, conjugated products are ionic, polar, less lipid soluble, less toxic and easily excretable from body. </p> <p> All reactions of pesticide metabolism are described using chemical structure with possible target sites and enzyme involved.

Total Pages: 62-96 (35)

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