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 cha...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 polymer chains with the amino groups of the enzyme.The resulting two CRL-pID 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(V_(max))and a decrease in the Michaelis constant(K_(m)),thus resulting in about three-fold increases in the catalytic efficiency(k_(cat)/K_(m)).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 zwitterion 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 promising for improving enzyme performance and deserves further development.展开更多
Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A por...Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A porous poly(vinyl acetate–divinyl benzene)microsphere coated by a zwitterionic polymer,poly(maleic anhydride-alt-1-octadecene)and N,N-dimethylethylenediamine derivative,was developed for CRL immobilization via hydrophobic binding.The catalytic activity,reaction kinetics,stabilities and reusability of the immobilized CRL were investigated.It demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous microsphere.The immobilized lipase(p2-MS-CRL)reached27.6 mg·g^-1 dry carrier and displayed a specific activity 1.5 times higher than free CRL.The increase of Vmax and decrease of Kmwere also observed,indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized lipase.Besides,p2-MS-CRL exhibited significantly enhanced thermal stability and pH tolerance.The improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer coating.This study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.展开更多
以表面活性聚合物马来酸十六双酯磺酸钠-丙烯酰胺聚合物(SH-16-AM)为研究对象,考察了聚合物溶液的界面张力、增黏性、耐盐性、耐剪切能力、耐温性和抗老化能力。实验结果表明,SH-16-AM具有较高的界面活性,在质量浓度为1.5 g/L时,它与大...以表面活性聚合物马来酸十六双酯磺酸钠-丙烯酰胺聚合物(SH-16-AM)为研究对象,考察了聚合物溶液的界面张力、增黏性、耐盐性、耐剪切能力、耐温性和抗老化能力。实验结果表明,SH-16-AM具有较高的界面活性,在质量浓度为1.5 g/L时,它与大庆原油的界面张力为1.008 m N/m;在质量浓度为2.0 g/L时,黏度为133.5 m Pa·s,且耐盐性、耐剪切能力、耐温性和抗老化性能均好于传统聚合物聚丙烯酰胺(HPAM)。室内岩心实验结果表明,SH-16-AM聚合物驱可在水驱基础上将最终采收率提高至60%左右,较HPAM聚合物驱高6百分点左右。展开更多
基金funded by the National Key Research and Development Program of China(2018YFA0900702)the National Natural Science Foundation of China(21621004).
文摘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 polymer chains with the amino groups of the enzyme.The resulting two CRL-pID 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(V_(max))and a decrease in the Michaelis constant(K_(m)),thus resulting in about three-fold increases in the catalytic efficiency(k_(cat)/K_(m)).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 zwitterion 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 promising for improving enzyme performance and deserves further development.
基金Supported by the National Natural Science Foundation of China(21621004,21878222).
文摘Enzyme immobilization has attracted great attention for improving the performance of enzymes in industrial applications.This work was designed to create a new support for Candida rugosa lipase(CRL)immobilization.A porous poly(vinyl acetate–divinyl benzene)microsphere coated by a zwitterionic polymer,poly(maleic anhydride-alt-1-octadecene)and N,N-dimethylethylenediamine derivative,was developed for CRL immobilization via hydrophobic binding.The catalytic activity,reaction kinetics,stabilities and reusability of the immobilized CRL were investigated.It demonstrated the success of the zwitterionic polymer coating and subsequent CRL immobilization on the porous microsphere.The immobilized lipase(p2-MS-CRL)reached27.6 mg·g^-1 dry carrier and displayed a specific activity 1.5 times higher than free CRL.The increase of Vmax and decrease of Kmwere also observed,indicating the improvement of catalytic activity and enzyme-substrate affinity of the immobilized lipase.Besides,p2-MS-CRL exhibited significantly enhanced thermal stability and pH tolerance.The improved performance was considered due to the interfacial activation regulated by the hydrophobic interaction and stabilization effect arisen by the zwitterionic polymer coating.This study has thus proved the advantages of the zwitterionic polymer-coated porous carrier for lipase immobilization and its potential for further development in various enzyme immobilizations.
文摘以表面活性聚合物马来酸十六双酯磺酸钠-丙烯酰胺聚合物(SH-16-AM)为研究对象,考察了聚合物溶液的界面张力、增黏性、耐盐性、耐剪切能力、耐温性和抗老化能力。实验结果表明,SH-16-AM具有较高的界面活性,在质量浓度为1.5 g/L时,它与大庆原油的界面张力为1.008 m N/m;在质量浓度为2.0 g/L时,黏度为133.5 m Pa·s,且耐盐性、耐剪切能力、耐温性和抗老化性能均好于传统聚合物聚丙烯酰胺(HPAM)。室内岩心实验结果表明,SH-16-AM聚合物驱可在水驱基础上将最终采收率提高至60%左右,较HPAM聚合物驱高6百分点左右。
