Molecular "wiring" of plasma amine oxidase: Green and enzyme friendly approaches

The study describes two approaches to enhance oxidoreductases. Both target molecular "wiring" of enzymes using green processes. The concepts were tested on plasma amine oxidase (PAO). In the first procedure PAO was transiently exposed to an ionic liquid (IL) in the presence of redox molecules, which resulted in partial unfolding. During subsequent dialysis, the enzyme refolded entrapping redox units and affording shorter distances for electron tunneling, hence a molecular "wire" to PAO's prosthetic groups. The other procedure described herein was totally reagentless, using high hydraulic pressure (HHP) to partially denature PAO (in the presence of redox molecules) followed by dialysis and refolding. The two approaches to enzyme "wiring" are discussed comparatively from the point of view of the parameters used during the procedure, residual enzyme activity, nature of the modifier, interaction between PAO and the redox molecules, and stability over time. The most active modified PAO (PAO-ME) from each series was tested in a biosensor for amine detection, toward applications in the food industry and clinical laboratory. Our approaches used "green" reagents (IL) and were made enzyme-friendly as well by the choice of "wires".