Controlling tyrosinase activity on charged polyelectrolyte surfaces: a QCM-D analysis

Area of Science:

• Biomaterials Science
• Enzyme Immobilization
• Surface Chemistry

Background:

• Enzyme immobilization is crucial for developing biosensors and biocatalysts.
• Understanding enzyme-polyelectrolyte interactions is key to controlling surface activity.
• Tyrosinase, a metalloenzyme, is relevant in various biotechnological applications.

Purpose of the Study:

• To investigate the real-time immobilization of tyrosinase onto polycationic and polyanionic surfaces.
• To assess the retained enzymatic activity and binding capabilities of immobilized tyrosinase.
• To elucidate the mechanisms governing enzyme-polyelectrolyte interactions and their effect on enzyme function.

Main Methods:

• Utilizing quartz crystal microbalance (QCM) for in situ monitoring of tyrosinase immobilization.
• Real-time measurement of enzyme binding to polyelectrolyte assemblies.
• Exposure of immobilized enzyme surfaces to flavonoids to quantify binding and activity.

Main Results:

• Tyrosinase immobilization and activity were successfully monitored in real-time using QCM.
• Enzyme activity was retained on polycationic films, evidenced by flavonoid binding.
• Enzyme activity was inhibited on polyanionic films, with no flavonoid binding observed.

Conclusions:

• Enzyme activity is dependent on the charge of the polyelectrolyte surface during immobilization.
• Strong electrostatic interactions, particularly ion-pair formation with the dicopper center, deactivate tyrosinase on polyanionic surfaces.
• Further research aims to generalize these findings to various metalloenzymes and polyelectrolyte architectures.