Conditional Reactivation of Lysozyme Nanosystems via Hydrophobic Ion Pairing

Enzyme-catalyzed reactions rely on the precise regulation of enzymatic activity to achieve high efficiency and specificity. Adjustment of conditions during the reaction is only one possibility, whereas timely activation and termination of enzymatic functions further tailor the outcomes. Existing methods for enzyme activation include temperature, pH, ultrasound, and magnetic and electric fields, but each approach struggles with limited applicability to different enzyme classes and faces challenges with reversibility. In our research, we employed hydrophobic ion pairing to modulate lysozyme activity through complexation with hydrophobic counterions, sodium docusate, and sodium laurate. The resulting complex agglomerates were stabilized with nonionic surfactants and characterized by their colloidal properties, including size and zeta potential. A fluorescence-based enzymatic assay was used to monitor the activity of the nanosystems under varying dissociation conditions. Lysozyme nanosystems with sodium docusate were completely inactivated, while those with sodium laurate retained only a partial activity. Increasing the ionic strength reversed the inactivation and restored enzymatic function. We developed a method for reversible, conditional modulation of enzymatic activity as a function of the ionic concentration. This work demonstrates a tunable strategy for regulating enzyme activity in cases where conventional control mechanisms are not suitable.