A new electrochemical sensor based on a Nafion, aminated reduced graphene oxide and chitosan functional membrane-modified glassy carbon electrode was proposed for the simultaneous detection of adenine and guanine. Fourier transform-infrared spectrometry (FTIR), transmission electron microscopy (TEM), and electrochemical methods were utilized for the additional characterization of the membrane materials. The prepared electrode was utilized for the detection of guanine (G) and adenine (A). The anodic peak currents to G and A were linear in the concentrations ranging from 0.1 to 120 μM and 0.2 to 110 μM, respectively. The detection limits were found to be 0.1 μM and 0.2 μM, respectively. Moreover, the modified electrode could also be used to determine G and A in calf thymus DNA.

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Abstract.A novel artificial peroxidase (AP) with highly catalytic efficiency was designed using hexadecyl trimethyl ammonium bromide (CTAB, 3 mM) nano-micelles and bovine heart cytochrome c (Cyt c, 0.5 ȝM) in 100 mM, pH 8.0 phosphate buffer at 25°C. The catalytic rate (k cat ) and Michaelis-Menten (K m ) of the AP were determined to be 0.311 ± 0.013 s -1 and 8.64 ± 0.6 ȝM. The catalytic efficiency was 0.0360 ± 0.0020 ȝM -1 s -1 (about 50% the efficiency of native horseradish peroxidase). The Ultraviolet-visible spectrophotometer and Circular Dichroism techniques were applied to study the properties of the CTAB-Cyt c nano-micelle. Designed AP can be applied instead of native horseradish peroxidase.

contributed equally to this work.Abstract-Glucose-oxidase-horseradish peroxidaseguaiacol coupled system was applied for glucose oxidase assay with high sensitivity and prefect reproducibility. The optimum pH value was 5.8. The Michaelis-Menten constant (Km) and Vmax were determined to be 30.0±1.0mM and 2.49±0.08μM/s, respectively, for the assay system at 25º C. The relative standard deviation was 2.8% for 31 times measurements of GOD activity. The GOD assay could be applied in conformational lock study on GOD. Results of bio-thermodynamics suggested that the number of contact area of GOD is two, which is consistent with the computation results by using Ligplot and Pymol.

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