We have demonstrated that gold nanoparticles (AuNPs) can effectively associate with enzyme through spontaneous adsorption to afford supramolecular complexes, resulting in a significant increase of its enzymatic activity. In this work, we embarked on a study of the interactions between the different-sized AuNPs and the substrate through quantifying the kinetic parameters (K-cat and K-m). The diversity of size allows us to probe the role of catalytic behaviors in modulating enzymatic activity.