Study on controllable enzymolysis by chiral capillary electrophoresis with an ultraviolet-visible responsive polymer membrane based L-asparaginase reactor

Abstract

Stimuli-responsive polymer enzyme reactors have become a major area of research interest, from their fundamental aspects to applications in bio-living science. However, the polymer materials, that enable the controllable enzymolysis based on ultraviolet-visible (UV)-responsive properties, have remained unexplored. Herein, an enzyme reactor was fabricated by immobilization of L-asparaginase on an UV-responsive porous polymer membrane (UV-PPMER), which consisted of poly(styrene-maleicanhydride-4-[(4-methacryloyloxy)phenylazo] benzoic acid) [P(St-MAn-MPABA)], and explored its controllable enzymolysis. By controlling the "on/off" switch of 365 nm UV irradiation, the configuration of polymer membrane surface changed to improve and tune the enzymolysis. Using L-asparagine (L-Asn) as the substrate, the enzymatic efficiency of the UV-PPMER was evaluated by a chiral capillary electrophoresis technique. Upon UV irradiation, the PMPABA moiety in the membrane changed from a trans- to a cisconfiguration and encapsulated the enzyme and substrate into a narrow cavity, further improving the enzymatic efficiency due to the confinement effect. It was found that the enzymatic reaction rate with the UV-PPMER under UV irradiation (13.3 mM min(-1)) was 4.5 times higher than that of UV irradiation was off (2.94 mM min(-1)). Additionally, the low cytotoxicity and excellent UV-responsivity of UV-PPMER were verified in the living cells and serum samples.