CBAL catalyzes the conversion of 4-chlorobenzoate (4-CB) to 4-chlorobenzoyl-coenzyme A (4-CB-CoA) by the two-step adenylation and thioester-forming reactions. 4-Chlorobenzoate (4-CBA) is an environmental pollutant derived from microbial breakdown of aromatic pollutants, such as polychlorinated biphenyls (PCBs), DDT, and certain herbicides. The 4-CBA degrading pathway converts 4-CBA to the metabolite 4-hydroxybezoate (4-HBA), allowing some soil-dwelling microbes to utilize 4-CBA as an alternate carbon source. This pathway consists of three chemical steps catalyzed by 4-CBA-CoA ligase, 4-CBA-CoA dehalogenase, and 4HBA-CoA thioesterase in sequential reactions.