Thermokinetic characterization of imipenem hydrolysis with metallo-β-lactamase CcrA from Bacteroides fragilis

In an effort to study on the antibiotic resistance in bacteria, we first report the thermokinetic parameters of the imipenem hydrolysis with B1 subclasses metallo-β-lactamase CcrA from Bacteroides fragilis  . The values of activation free energy ΔG≠θ is 87.54 ± 0.03, 88.78 ± 0.03, 89.90 ± 0.04 and 91.06 ± 0.02 kJ mol−1 at 293.15, 298.15, 303.15 and 308.15 K, respectively, the activation enthalpy ΔH≠θ is 19.10 ± 0.01 kJ mol−1, the activation entropy ΔS≠θ is −233.56 ± 0.09 J mol−1 K−1 and the apparent activation energy E is 21.598 kJ mol−1. The results reveal that the imipenem hydrolysis catalyzed by CcrA is an exothermic and spontaneous reaction with reaction order of 1.4, and has a lower ΔH≠θ and ΔS≠θ than the cefazolin hydrolysis with same enzyme.

► First report the thermokinetic parameters of imipenem hydrolysis with CcrA. ► The hydrolysis is a spontaneous and exothermic reaction with order of 1.4. ► Imipenem hydrolysis with CcrA has a lower ΔH≠θ and ΔS≠θ than the cefazolin hydrolysis with same enzyme. ► Imipenem hydrolysis with CcrA had a 46-fold faster reaction rate than with ImiS.