Gas-liquid flow-induced permeabilization of phospholipid bilayer membranes for regulating catalytic performance of liposome-encapsulated bovine liver catalase

摘要

The catalytic performance of bovine liver catalase-containing liposomes (CALs) was regulated by use of the gas-liquid flow generated in an external loop airlift bubble column The CALs were prepared by extruding through a membrane with the mean pore diameter D-p of 30, 50, 80, 100, 200 or 400 nm. The airlift was operated at 40 degrees C for 5h at the superficial gas velocity U-G of 0.47-1.9 cm/s. Significant deactivation of free catalase was observed in the airlift because of its structural alteration at the gas-liquid interface On the other hand, the activity of CAL prepared at D-p of 100 nm was stable in the airlift almost regardless of U-G because the liposomal interior is free of gas phase The CAL prepared at D-p of 400 nm was structurally unstable while the membrane integrity of smaller CALs was maintained in the airlift operated even at the highest U-G The reactivity of liposomal catalase to H2O2 added to the liquid bulk of the airlift increased at 40 degrees C in the U-G-dependent manner This was because the permeation of H2O2 through the CAL membranes was enhanced through the gas-liquid flow-induced structural perturbation of the membrane Modulation of membrane permeability of liposomes with the gas-liquid flow is suggested to be a versatile method for regulating catalytic performance of liposomal enzymes without employing any chemical and biological means