Carboxylesterases are serine hydrolases that catalyze the hydrolysis of esters, amides, thioesters and carbonates. These enzymes lack substrate specificity, so they are involved in many diverse physiological and toxicological processes . Thus, human CES participate in lipid metabolism. Likewise, they inactivate hormones such as ghrelin and the juvenile hormone of insects, and contribute to pesticide detoxification. In plants, CE activity contributes to the metabolism and disposition of secondary metabolites and xenobiotic. Human CE activity is also implicated in both metabolism and activation of a vast range of drugs and prodrugs (i.e., inac-tive drugs that need to be metabolized to gain pharmacologicalactivity)