Direct electrochemistry of heme undecapeptide in aqueous surfactant solutions: The effect of hydrophobicity and axial ligation on redox potential of heme

Abstract

Direct electrochemistry of heme undecapeptide (microperoxidase) in micellar solution has been achieved for the first time. Results show a smooth increase in the E1/2 with increase in surfactant concentration. The diversity of redox potentials of the heme in various redox hemeproteins is an important topic of investigation in recent years. The origin of this diversity can either be variation in axial ligation or hydrophobicity of the heme pocket in different hemeproteins. We report here that association of heme undecapeptide (microperoxidase) with aqueous detergent micelles can indeed modulate the redox potential of the heme to a sizable extent. Micellar environment mimics the hydrophobicity of the protein cavity. Thus, our results demonstrate on how the hydrophobicity can tune the redox potentials of hemeproteins.