On the Dehalogenation Mechanism of 4-Chlorobenzoyl CoA by 4-Chlorobenzoyl CoA Dehalogenase: Insights from Study Based on the Nonenzymatic Reaction

摘要

The conversion of 4-chlorobenzoate to 4-hydroxybenzoate is carried out by first esterifying 4-chlorobenzoate by coenzyme A, and the resulting 4-chlorobenzoyl CoA serves as substrate for the 4-chlorobenzoyl CoA dehalogenase. To gain a better appreciation of the catalytic mechanism and factors controlling the catalytic efficacy of this dehalogenase, the nucleophilic aromatic substitution reaction between 4-Cl-Ph-CO-SCH_3 and CH_3COO~- was investigated in detail in both gas phase and solution (the-CH_2COO~- entity of ASP 145 is the enzyme nucleophile).