Glucose Oxidase And Its New Biosensor

The research object of this paper is glucose oxidase.The thermal decomposition process was studied by various techniques.Furthermore,the contact areas and main interactions involving the contact area were generated by using Py MOL and Ligplot+.At the same time,graphene and multi-walled carbon nanotube composites modified electrode,electrochemical studies of glucose oxidase were carried out.A novel biosensor for the direct electrochemistry of GOD and the high sensitivity to glucose in nanocomposite modified electrode was successfully constructed.The article is divided into three parts:In the first part,design a method to measure the activity of glucose oxidase.The method is measured by a spectroscopic instrument: UV-visible spectroscopy.Glucose-oxidase-horseradish peroxidase-guaiacol coupled system was applied for glucose oxidase assay.The repeatability of the assay was checked by determining the activity of GOD sample respectively,and the mean value of the GOD activity was calculated to be 110 ± 2 U/mg.The determination GOD activity value is consistent with the data provided by sigma(Type VII from Aspergillus niger,Activity?100 U/mg).The optimum p H value was 5.5.The Michaelis-Menten constant(K m)and V max were determined to be 30.0 ± 1.0 m M and 2.49 ± 0.08 ?M/s.The method has good sensitivity,reproducibility,and measurement accuracy.In the second part,after determining the measurement method,according to the theory of conformation lock,results of bio-thermodynamics measured that the number of contact area of GOD is two.Thus deduced the enzyme in the dimerization and aggregation process protein hydrophobic environment changes by fluorescent probe(ANS).The use of circular dichroism instrument,combined CDNN software to calculate the change in the ?-helical.In addition,the particle size of the enzyme solution was measured at different temperatures using a nanoparticle analyzer.In the third part,direct electrochemistry of glucose oxidase was realized when it was immobilized on a nanocomplex modified glassy carbon electrode,and the nanocomplex was composed of graphene and multi–walled carbon nanotubes.The nanocomposites are more conducive to transfer electron between the electrode surface and glucose oxidase activity center.Qualitative analysis of the biological compatibility of two materials on glucose oxidase by UV-visible spectroscopy and FTIR spectroscopy.Using cyclic voltammetry(CV)to measure electrochemical and electro-catalyzed reaction of glucose oxidase that modified electrode,experiment results showed that,the modified electrode showed a pair of well-defined redox peaks,the electron transfer rate constant(k S)was evaluated to be 0.87 s-1,and electroactive surface density was 1.54×10-10 mol/cm-2.The apparent Michaelis-Menten constant(K m app)was 4.09×102 ?M,linear detection range: 40-1000 ?M,and the modified electrode with better stability,The signal attenuation is small after placed day and night,and modified electrode has good anti-interference ability when detected the substrate.A third generation biosensor for detecting Glucose concentration was successfully constructed under laboratory conditions.