Techniques for measuring the activity of carboxylic acid:CoA ligase and acyl-CoA:amino acid N-acyltransferase: the amino acid conjugation pathway.

A wide variety of xenobiotic carboxylic acids are metabolized to their amino acid conjugates via a pathway that exists primarily in liver and kidney. This conjugation occurs in a two-step pathway catalyzed by two distinct types of enzymes, ligases and transferases. Measurements of acyl-CoA ligase activity include monitoring the rate of appearance of AMP or PPi, or the CoA adduct. N-acyltransferases catalyze formation of an amino acid conjugate from the CoA-activated intermediate, releasing CoA. This reaction is monitored by following the release of free CoA or the disappearance of the acyl-CoA adduct.