Dehaloperoxidase (DHP) is a unique dual-function hemoglobin with enhanced peroxidase activity that also transports oxygen, making it very attractive for biochemical investigation and biosensor development.  Accordingly, DHP's redox mechanism, interfacial properties and immobilization are of great interest.  To these ends, optimal conditions for conducting cyclic voltammetry of both dissolved DHP (diffusional) and reversibly adsorbed DHP (diffusionless) have been established.  Stable quasi-reversible CVs for the ferric/ferrous DHP couple were obtained for anaerobic and aerobic environments using mixed COOH/OH-terminated SAM-modified Au electrodes.  ET kinetics, reduction potentials, and dioxygen binding for diffusional DHP were characterized using digital simulation.  Adsorption of electroactive DHP reported here constitutes the first example of reversible immobilization of a globin.  Diffusional voltammetry and adsorption of DHP were sensitive to ionic strength, indicating a dominant role for interfacial electrostatic interactions.  Results will be discussed in light of Hoffman's dynamic docking model for protein-protein interactions.

Electrochemical characterization of dehaloperoxidase: Redox mechanism, thermodynamics, and interfacial properties

244th National Meeting (2012)

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