Figure 3
From: Protecting enzymatic function through directed packaging into bacterial outer membrane vesicles
Enzyme activity post iterative freeze-thaw.
(a) Freeze-thaw stability test of PTE/OMVN compared to free PTE-SC and free PTE lacking the SpyCatcher fusion. Four cycles of freeze-thaw between −80 °C and RT were carried out and the percent PTE activity was directly compared via initial velocity measurements. Both free proteins exhibited extensive inactivation due to freeze-thaw cycles with PTE exhibiting slightly higher stability. OMV packaged PTE-SC exhibited heightened resistance to inactivation from freeze-thaw retaining 93% activity after four cycles. (b) PTE freeze-thaw stability was also assayed in the presence of 20% glycerol and commixed with native OMV demonstrating no improvement in resistance to inactivation due to multiple freeze-thaw cycles. All data represents means (±one standard deviation) of triplicate experiments.
