Catalytic efficiency of dehaloperoxidase A is controlled by electrostatics - application of the vibrational Stark effect to understand enzyme kinetics

► DHP A is a dual function protein capable of oxidizing toxic trihalophenols to dihaloquinones. ► Kinetics are controlled by electrostatics since enzyme and substrate are both negatively charged. ► Stark probe molecule, 4-mercaptobenzonitrile, used to probe protein surface electrostatics. ► MD simulations confirm that Stark probe reports changes to overall protein electrostatics. ► Linear correlation between vibrational Stark effect and kinetic data reveal electrostatic control in DHP.