State Key Laboratory of Molecular Engineering of Polymers and Department of Macromolecular Science, Fudan University , Shanghai 200433, China.
Langmuir. 2016 Nov 8;32(44):11573-11579. doi: 10.1021/acs.langmuir.6b02573. Epub 2016 Oct 24.
Polycatalytic enzyme complexes made by immobilization of industrial enzymes on polymer- or nanoparticle-based scaffolds are technologically attractive due to their recyclability and their improved substrate binding and catalytic activities. Herein, we report the synthesis of polycatalytic complexes by the immobilization of nonprocessive cellulases on the surface of colloidal polymers with a magnetic nanoparticle core and the study of their binding and catalytic activities. These polycatalytic cellulase complexes have increased binding affinity for the substrate. But due to their larger size, these complexes were unable to access to the internal surfaces of cellulose and have significantly lower binding capacity when compared to those of the corresponding free enzymes. Analysis of released soluble sugars indicated that the formation of complexes may promote the prospect of having consistent, multiple attacks on cellulose substrate. Once bound to the substrate, polycatalytic complexes tend to remain on the surface with very limited mobility due to their strong, multivalent binding to cellulose. Hence, the overall performance of polycatalytic complexes is limited by its substrate accessibility as well as mobility on the substrate surface.
固定化在聚合物或基于纳米粒子的支架上的工业酶的多催化酶复合物由于其可回收性以及改善的底物结合和催化活性在技术上具有吸引力。在此，我们报告了通过将非程序性纤维素酶固定在具有磁性纳米颗粒核的胶体聚合物表面上来合成多催化复合物，并研究了它们的结合和催化活性。这些多催化纤维素酶复合物对底物的结合亲和力增加。但是，由于它们的尺寸较大，这些复合物无法进入纤维素的内部表面，并且与相应的游离酶相比，其结合能力明显降低。释放的可溶性糖分析表明，形成复合物可能有助于对纤维素底物进行一致的多次攻击。一旦与底物结合，由于与纤维素的强多价结合，多催化复合物往往由于其在表面上的强固定而在表面上保持非常有限的迁移性。因此，多催化复合物的整体性能受到其底物可及性以及在底物表面上的迁移性的限制。
