Daao Immobilize On Pt-functionalized Zirconium Framework Mimicking Multi-enzyme Catalysis

D-amino acid oxidase(DAAO)will be accompanied by by-product hydrogen peroxide(H2O2)in the process of catalyzing D-amino acid,which reduces the catalytic efficiency of the enzyme and inhibits the formation of the main reaction product.In this research,the hollow structure Zr-HPSNs-NH2@Pt(KX_Zr-HPSNs-NH2@Pt)catalyst,which loading Pt was prepared fistly,and the DAAO was immobilized on KX_Zr-HPSNs-NH2@Pt,which make Pt and DAAO get closer in molecular distance.Therefore,the Pt nanoparticles will decompose H2O2 produced by DAAO rapidly,then generate oxygen.Simultaneously,the oxygen(O2)produced by Pt nanoparticles will be used to oxidize FAD adequately and H2O2 also be generated.This reaction cycle from H2O2 to O2 to H2O2 between Pt nanoparticles and DAAO pushed the main reaction to speed up.The initial rate of enzyme reaction also has shown that the catalytic efficiency of DAAO/Zr-HPSNs-NH2@Pt_KX system is nearly twice that of free DAAO,indicating that this simulated system has a high efficiency of catalysis.At the same time,we use SEM,FT-IR,XPS,TEM,STEM,EDS,and SIM methods to verify our results.The experimental results fully show that the catalytic systems have been successfully constructed.Finally,in the further study of the multi-enzyme system,we can use more precious metals apart from Pt nanoparticles.Alternatively,other oxidases can be used to immobilize the D-amino acid oxidase on the carrier to provide a more extensive analog multi-enzyme system.