Enzyme-polymer conjugates are complex molecules with great practical significance.This work was designed to develop a novel enzyme-polymer conjugate by covalently coupling a zwitterionic polymer with side dimethyl chains(pID)to Candida rugosa lipase(CRL)via the reaction between the anhydrides of poly-mer chains with the amino groups of the enzyme.The resulting two CRL-plD conjugates with different pID grafting densities were investigated in term of the catalytic activity,stability and structural changes.In comparison with native CRL,both the CRL conjugates displayed 2.2 times higher activity than the native enzyme,and showed an increase in the maximum reaction rate(Vmax)and a decrease in the Michaelis con-stant(Km),thus resulting in about three-fold increases in the catalytic efficiency(kcat/Km).These are mainly attributed to the activation of lipase by the hydrophobic alky side chains.Moreover,the thermostability and pH tolerance of the lipase conjugates were significantly enhanced due to the stabilizing effect of the zwit-terion moieties.For instance,a five-fold increase of the enzyme half-life at 50℃for the high-pID conjugated CRL was observed.Spectroscopic studies reveal that the pID conjugation protected the enzyme in the changes in its microenvironment and conformation,well correlating with enhanced activity and stability of lipase conjugates.The findings indicate that enzyme conjugation to the zwitterionic polymer is promis-ing for improving enzyme performance and deserves further development.

Chunyu Zhang;Yan Sun;Xiaoyan Dong

Department of Biochemical Engineering,School of Chemical Engineering and Technology and Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education),Tianjin University,Tianjin 300350,China;College of Life Sciences,Yantai University,Yantai 264005,China

中国化学工程学报（英文版）

[1]Chunyu Zhang;Yan Sun;Xiaoyan Dong-.Conjugation of a zwitterionic polymer with dimethyl chains to lipase significantly increases the enzyme activity and stability)[J].中国化学工程学报（英文版）,2022(07):48-53

pID,plD,alky,zwit

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