title: Catalytic activity and stability of glucose oxidase/horseradish peroxidase co-confined in macroporous silica foam.
abstract: Investigation of the catalytic activity and stability of enzymes in confined nano/microspace provides valuable contributions to the fundamental understanding of biological reactions taking place on a mesoscopic scale within confined spaces. In this paper, macroporous silica foam (MSF) is used as a nanoreactor to co-confine glucose oxidase (GOD) and horseradish peroxidase (HRP). Then, the enzymatic cascade reactions, which act in tandem inside nanoreactors, for oxidation of glucose and 3,3',5,5'-tetramethylbenzidine (TMB) were studied. The catalytic kinetic parameters of apparent Michaelis constant (K(m)(app)) and maximum rate (V(max)) were obtained from Lineweaver-Burk plot by UV-vis spectrometry. Results showed that the catalytic activity of the co-confined enzymes is reduced compared to that of free enzymes in solution at room temperature. The stabilities of co-confined enzymes in denaturing agents, such as guanidinium chloride (GdmCl) and urea, were higher than those of free enzymes in solution. When employing a co-confined bienzyme system as a biosensor for the detection of glucose, a wider linear range of glucose was obtained for the co-confined bienzyme system than for free enzymes in solution.
authors.affiliation: School of Chemistry and Chemical Engineering, Southeast University Jiangning, Nanjing 211189, People's Republic of China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Cao
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Jiachao
authors.initials: J
authors.lastname: Yu
authors.forename: Jing
authors.initials: J
authors.lastname: Qian
authors.forename: Songqin
authors.initials: S
authors.lastname: Liu
mesh_terms: D001234:Aspergillus niger / Q000201:enzymology; D001560:Benzidines / Q000737:chemistry; D055162:Biocatalysis; D015374:Biosensing Techniques; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D005949:Glucose Oxidase / Q000737:chemistry* / Q000378:metabolism*; D006735:Horseradish Peroxidase / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D016062:Porosity; D011487:Protein Conformation; D011489:Protein Denaturation; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D001560:Benzidines; D004800:Enzymes, Immobilized; C021758:3,3',5,5'-tetramethylbenzidine; D012822:Silicon Dioxide; D005949:Glucose Oxidase; D006735:Horseradish Peroxidase; D005947:Glucose