Specific Immobilization Of D-Amino Acid Oxidase On Hematin-Functionalized Support Mimicking Multi-Enzyme Catalysis

D-amino acid oxidase (DAAO) catalytic D-amino acid to generate the corresponding alpha keto acid, accompanied by by-product hydrogen peroxide (H2O2). In the research, D-amino acid oxidase modified connection an elastin-like polypeptide (ELP), and the modified enzyme (ELP-DAAO) was immobilized on multi-walled carbon nanotubes (MWCNTs). MWCNTs were functionalized with hematin firstly, then the ELP modified DAAO (ELP-DAAO) was immobilized on the functionalized MWCNTs by coupling to the hematin. This orientation enables the fixation of ELP-DAAO and hematin distance in space relative to the molecular level close. This molecule close distance makes the ELP-DAAO catalytic produce H2O2 can be rapidly decomposed by hematin. At the same time, the resulting oxygen (O2) has been used to adequately oxidized DAAO coenzyme-reduced state flavin adenine dinucleotide (FAD), and generate H2O2. The forming of a H2O2?O2? H2O2 circle between the DAAO and hematin, which has been demonstrated that the catalytic system loop as a driving force accelerating the main reaction. The enzyme kinetics has shown that the ELP-DAAO/hematin-CNT conjugate exhibited a catalytic efficiency more than three times that of free ELP-DAAO. Thereby, our research successfully constructed an efficient simulation of multi-enzymatic system.In addition, the experimental process for the construction of the catalytic system were characterized with the high resolution transmission electron microscopy (TEM), infrared spectroscopy (FT-IR), X-ray electron energy spectrum (XPS) and ultraviolet-visible spectra (UV-vis) methods, The experimental results fully show that the catalytic systems have been successfully constructed.Finally, for the efficient enzyme immobilized catalytic system further research. On the one hand, on the immobilized carrier, we can use other nano or micro material instead of MWCNTs. On the other hand for DAAO in this experiment can also be used in other oxidase replacement, to form a more wider mimicking multiple enzyme catalytic systems.