Figure 7.

Enhancing PTE activity using PTE-QD conjugates. Researchers have seen an increase in the catalytic activity of PTE when immobilized to the surface of QD NPs. In studies described by Breger et al., PTE was attached to CdSe NPs using an oriented assembly of the enzyme via a C-terminal His₆ amino acid sequence (schematic in the upper panel). Here the hydrolysis of paraoxon by PTE was monitored at 405 nm to assess enzyme activity for both free PTE and PTE immobilized to two QD NPs. Significant changes in the rate of initial velocity for PTE were observed when the enzyme was immobilized to 525 nm (B) and 625 nm (C) QDs. The rate of catalysis for free enzyme (A) was compared to each PTE-QD structure at varying ratios of nanoparticle to enzyme. In each instance the rate of reaction was markedly improved compared to the free enzyme control. Reproduced with permission (Breger et al., 2015a), Copyright American Chemical Society 2015.