Benzoate and ATP react with coenzyme A to form benzoyl CoA, AMP, and pyrophosphate (Vessey et al. 1999, 2003). Two human CoA ligases have been characterized that catalyze this reaction efficiently in vitro: acyl-CoA synthetase medium-chain family member 1 (BUCS1) (Fujino et al. 2001) and xenobiotic/medium-chain fatty acid:CoA ligase (Vessey et al. 2003). Their relative contributions to benzoate metabolism in vivo are unknown.