Electrical Field Reversibly Modulates Enzyme Kinetics of Hexokinase Entrapped in an Electro-Responsive Hydrogel

In this paper, the potential use of electro-responsive poly(acrylic acid) (PAA) gels as reversible enzyme activity regulators is analyzed. This was evaluated by measuring the glucose conversion by hexokinase embedded PAA hydrogels under external electrical stimuli. Hexokinase physically entrapped within PAA gels showed a significant increase in activity under an electrical stimulus as compared to in the absence of a stimulus. Kinetic studies revealed that the change in reaction rate could be attributed to the change of Vmax under a stimulus, while Km was unaffected by the stimulus, which suggested that the increase in reaction rate under an electrical stimulus was due to increased accessibility of the active site. Optimum stimuli-responsive behavior that resulted in maximum conversion under a stimulus and minimum conversion in the absence of a stimulus was obtained at 5.5 pH and 30 °C. The significant difference between the pH optima for the entrapped enzyme and the pure enzyme can be attributed to the ac...