In-situ activity of α-amylase in the presence of controlled-frequency moderate electric fields

Abstract

Studies on the effects of electric fields on enzymatic activity have typically focused on post-treatment residual activity. However, information on their effects on in-situ activity is scant. The objective of this study was to investigate the effect of controlled-frequency Moderate Electric Fields (MEF) on α-amylase activity. Relative α-amylase activities were measured in-situ in the presence of an electric field (1 V/cm, 1 Hz-1MHz) at 60 °C, with a zero electric field at the same temperature serving as a control treatment. Results show a significant nonthermal effect of electric field frequency on α-amylase activity, with up to 41% enhancement of the activity in the 1–60 Hz frequency window. At higher frequencies, activity was either unaffected, or slightly inhibited by the presence of the electric field. Molecular dynamics simulation results show that in the 1–60 Hz frequency window, the translational electrophoretic enzyme displacement approaches the intermolecular spacing of water. Interestingly, enzyme rotational motion transitions from oscillatory behavior to full rotation below 60 Hz. Application of higher frequencies restricts the electrophoretic displacement of the enzyme due to rapid reversal of the direction of the electric field.