ABSTRACT
Conjugation with amino acids is an important route in the biotransformation of a variety of xenobiotic carboxylic acids in a number of animal species. These reactions involve the formation of an amide or peptide bond between the carboxyl group of the xenobiotic and the amino group of an endogenous amino acid. Unlike the majority of the conjugation reactions, described elsewhere in this volume, in which the xenobiotic reacts with a ‘high-energy’ endogenous molecule, generally a nucleotide, the xenobiotic acid is activated in the carboxyl moiety to a ‘high-energy’ intermediate prior to the transfer of the acyl group to the endogenous molecule.
