(650g) Concanavalin Α Enabled High Performance Enzyme Cascades on Magnetic Nanoparticles

Yong, Y., Key Lab for Industrial Biocatalysis, Ministry of Education,
Ge, J., Tsinghua University
Liu, Z., Key Lab of Industrial Biocatalysis, Ministry of Education, Tsinghua University
Concanavalin A (ConA) is a lectin that specifically binds to carbohydrates containing non-reducing terminal α-D-mannosyl or α-D-glucosyl moieties. Here we present a facile and aqueous method preparing multiple glycolenzyme catalysts using ConA coated magnetic nanoparticles (ConA-MNP). The first step is to from a ConA layer on the surface of MNP (ConA-MNP) by crosslinking with glutaraldehyde. Then glycoenzymes were agglutinated on the surface of ConA-MNP spontaneously, followed by crosslinking with glutaraldehyde.

The resulted GOx-HRP@ConA-MNP showed an over 80% residual activity compared to their native counterparts in solution. In contrast, merely no activity was observed when the enzymes were directly immobilized on MNP via crosslinking with glutaraldehyde. The GOx-HRP@ConA-MNP retained over 90% of the initial activity after 10 cycles. Above mentioned procedure was applied to form GOx-Cat@ConA-MNP for catalyzing the conversion of glucose to gluconic acid. It was evidenced by both structural characterization and reaction kinetics that the co-localization of the cascade enzymes enabled a substrate looping between two enzymes, i.e., oxygen produced by Cat was confined to GOx producing H2O2 as a substrate for Cat. As a result GOx-Cat@ConA-MNP achieves 91% glucose conversion in 75 minutes whereas the aqueous GOx and Cat reached a conversion of 86%. The GOx-Cat@ConA-MNP retained 99% after 8 cycles with a glucose conversions over 90% in each run.

The high catalytic performance and the ease of operation makes the multiple enzymes @ConA-MNP appealing for enzyme cascades for various applications.