title: Enhancement of enzymatic activity by magnetic spherical polyelectrolyte brushes: a potential recycling strategy for enzymes.
abstract: Interactions between amyloglucosidase and magnetic spherical polyelectrolyte brushes (MSPB) were studied by turbidimetric titration, which reveals reversible and tunable behaviors of pH-dependent enzyme-SPB binding. Quantitative thermodyanmic parameters including binding affinity and stoichiometry between enzyme and SPBs were further measured by isothermal titration calorimetry (ITC). A large amount of enzyme can be loaded in MSPB without loss of MSPB stability. We demonstrated that the enzymatic activity of amyloglucosidase bound in MSPB could be greatly enhanced (catalytic reaction rate, k(bound) = 1.36k(free)) compared to free enzyme acitivity in solution. This is tremendous improvement from other carrier systems that usually lead to a significant decrease of enzymatic activity. Both the high enzyme loading capacity and the enhancement of the catalytic activity probably arise from the Coulombic interactions between the enzyme and MSPB. These findings provide a practical strategy for enhancement of enzyme activity and enzyme recycling by MSPB.
authors.affiliation: State Key Laboratory of Chemical Engineering, East China University of Science and Technology , Shanghai 200237, China.
authors.forename: Yisheng
authors.initials: Y
authors.lastname: Xu
authors.forename: Siyi
authors.initials: S
authors.lastname: Wang
authors.forename: Haoya
authors.initials: H
authors.lastname: Han
authors.forename: Kaimin
authors.initials: K
authors.lastname: Chen
authors.forename: Li
authors.initials: L
authors.lastname: Qin
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Xuhong
authors.initials: X
authors.lastname: Guo
mesh_terms: D000327:Adsorption; D001234:Aspergillus niger / Q000201:enzymology; D004573:Electrolytes / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry / Q000378:metabolism*; D060526:Magnetic Fields; D010316:Particle Size; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D013499:Surface Properties
chemical_list: D004573:Electrolytes; D011108:Polymers; D005087:Glucan 1,4-alpha-Glucosidase